to make my self a Party on either side at this time seeing the fineness of structure and dignity of functions are sufficient to give preference to one above another and to render it more worthy of a particular consideration And this part I take to be the Brain the delicacy of whose structure is such that with no little resemblance to its divine Author whilst it gives us the greatest and clearest discoveries of other things lies most concealed it self And seeing all that Mystick Knowledge which in ancient times in the eyes especially of the Vulgar appeared meer Necromancy or Witchcraft as well as all the Curious Discoveries of more modern Ages upon the whole subject of Nature now going under the more familiar and proper term of Refined Sence or Philosophy hath been meerly owing to a more acurate knowledge of the parts and modification of Matter I see not any more likely way of conquering the difficulties yet behind upon any particular subject than the endeavouring after a further and more nice scrutiny into it by such means and experiments as serve to bring its most minute parts and texture under the test of Sence which so assisted doth the same office to the discerning faculty at good artificial Glasses do to it bringing the Object and Judgment to such a nearness that even the first Link of the Chain becomes discernable and the mechanical proceedings of Nature so highly instructive to the Understanding in its finding out and assigning proper Causes to Effects much more obvious and intelligible I shall therefore treat this Noble Part after the aforesaid manner with all the Justice I can leaving those invisible and almost divine things called Animal Spirits to be treated of more at large by those more illuminated Philosophers who see best when their Eyes are put and content my self with making an inquiry into and giving a description of whatsoever upon this Subject by Dissection shall offer it self as an Object of our Senses THE ANATOMY OF THE BRAIN CHAP. 1. Of the Anatomy of the Brain THE topmost part or Olla of the Cranium being removed the first part of the Brain that comes in view is the Dura Mater which with the subjacent Pia Mater is accounted only an improper part of the Brain strictly so called however of great use in many respects to it 'T is by Spigelius and other Anatomists reckon'd and I think not undeservedly the thickest and hardest Membrane of the whole Body enclosing the whole Brain properly so called somewhat losely sticking almost inseparably to the Basis of the Cranium and to the top and sides under the Coronal Sagittal and Lamdocid Sutures very fast by the Sinus's whose description will come in another place In some places of the upper part of the Cranium which on each side of the Sagittal Suture or Vertex are called Ossa Bregmatis it adheres not to the Bone notwithstanding the positive Opinion of Van Roonhuyse Roonh p. 149. in his Leiter to Du Foy to the contrary who for that very reason would fain take away in a great measure the use of the Trepan and Trefoyne and altogether the use of the Instrument called Decussorium which skilful Surgeons do often make use of to make room for the discharge of subsided matter below the fractur'd place in many Accidents of the Brain 'T is very discernably double as Columbus and several others formerly Col. p. 348 and Vieussenius lately have observed having very strong and large Fibres on the inside but very small Vienss p. 3. and hardly visible on that side next the Skull as appeared to me after having first let it lye a little time in bolling or at least very scalding Water But as to the distribution of the double sort of Fibres on each side this Membrane I could not by any means find them agreeing with the description Vieussenius hath given of them as running in an oblique semicircular manner externally from before backwards and in the same figure internally from behind forwards but far otherwise on the inside where they are very strong they seem manifestly to have three originals from the top part of the Processus Falcatus before behind and in its middle those before running in a curved manner backwards half the length and a great width of the Dura Mater and those behind running after the same manner forwardly with this difference that a great number of them bend soon after their rise from that process in a kind of a semilunary way to it again a little on this side the rise of the middle Series of Fibres others of them making a bigger arch after having stretched themselves wider upon the Dura Mater bend back again to and terminate in the Falx a little beyond the rise of the aforesaid middle Series of Fibres Those from the middle part of the Falx run backwardly but less curved than the rest terminating as the Fibres which arise backwardly do at some distance from the Process in the inward Superficies of the Dura Mater As to those belonging to the exernal side or second Lamina of the Dura Mater they are extream small and obscure running from behind forwards Besides these there are no less remarkable ones belonging to the Falx it self of two sorts of Orders the one running streight about half the length of it on its upper part from before backwards the other transverse from the inferiour or fifth Sinus to the superiour or third on the hinder part of the Process and are most conspicuous there as the other are towards its foremost part As to the Use of those Fibres it may be remembred that this Membrane consists of two Lamina's between which the Veins which reduce the Blood from the Arteries which furnish the whole Brain with it run for some space after the manner of the Ureters in the Bladder in large Trunks before they enter the Sinus so that the Fibrous Constitution of this Membrane here where the Blood-vessels are largest together with the curved entrance of them into the Sinus especially in an erect position of the Body do the office of Valves support the weight and promote the ascent of the Blood But that which is most considerable is this That if the inward Lamina of this part which makes the inferiour and lateral part of the Sinus was not in some measure furnish'd with additional strength on this side suitable to that which it hath on the other by reason of its cohesion to the Skull the Blood which is continually running through it with no small rapidity especially in great plenitude of the Vessels or preternatural Ebulitions would frequently burst out or at least cause such distentions as could not but be very injurious to a part so very exquisitely sensible yet notwithstanding tho' Nature seems plainly to have made a double provision against such Accidents by the transverse Ligaments within the Sinus and these strong and numerous Fibres without I have rarely open'd any strangled Body where some
them both reckoned the original of the second proper Integument of the Spinal Marrow which Tulpius first discovered Tulp cent 1 obs 29. Vienssen p. 143. par 2. and Vieussenius supposes to be a Duplicature of the Pia Mater in that part only Now that there was a middle Membrane in some parts of the Brain and particularly at the Basis of the Cerebellum from whence it 's continued down to the Spinal Marrow constituting the second proper Integument of that part as afore-mentioned I had long since-observed but whether it be another absolute distinct Membrane from that other subjacent one by the aforesaid Authors properly named the Pia Mater and common to the Spinal Marrow with the Brain it self like as is this other second middle one too or only one and the same Membrane double as consisting of two Lamina's may well be doubted of Wherefore for satisfaction concerning this difficulty I have lately made the strictest enquiry possible and that in a subject most likely to afford a decision in such a Controversie and this was an Human Brain extreamly hydropical where there was no Cavity or Interstice without abundance of Water extravasated insomuch that where ever according to the natural construction of Parts there was any larger than ordinary duplicature of this Membrane as there are at the end of the Calamus Scriptorius betwixt the superincumbent Cerebellum and Medulla Spinalis in the Isthmus or space betwixt the Cerebrum and Cerebellum upon the Processes called Nates and Testes in the depressed part also of the Brain between the beginning of the Annular Process and the first appearance or coming out of the Olfactory Nerves by Vesalius taken notice of and called a Process of the Pia Mater Visal p. 794 there was found a great deal of Water distending this Duplicature much beyond its natural limits so that by way of consequence if these Cavities were only Interstices of two different Membranes distinctly investing the Brain and not a Duplicature only of one and the same the Water would then probably have insinuated it self betwixt them and made them to have appear'd far different from what they did agreeable to what it hath often been found to do in some Dropsies of the Belly where the Water hath been found so to have divided or parted the double Membrane of that Region call'd Peritoneum as to have render'd it capable of containing the quantity of fifteen Gallons of Water and upon a discharge of the same after death by cutting the external Lamina of that Membrane the other inward one being yet unknown to the Dissecter left whole to have imposed upon the Spectators and those very sagacious ones so as that at first sight till after having recollected themselves Job Meiâ—r Obs 52. and divided the other second Lamina too they thought the Bowels of this part to have been wanting but contrary to this Event in this Subject I found this Membrane entire and free from any divulsion throughout its whole circumference excepting the places afore taken notice of However supposing the like conformation here in this with the Membranes of the other parts I attempted to divide it and did so successfully in many parts of it but most readily in the beginning of the superficial Plicatures of the cortical part of the Brain where there are naturally small Interstices betwixt which many of the Blood-vessels creep into and immerge themselves in the cortical and medullary parts thereof So that I think there cannot remain any further scruple of its being only a double and not two distinct Membranes of the Brain Bidloo very truly observes this first or middle Membrane by him so called by me only the first or one Lamina of a double Membrane to be thinner than the Dura Mater above it and thicker than the other Membrane or Lamina under it which last most properly it is that insinuates it self through all the close Plicatures of the Brain and that as by frequent inspection I have often observed not in a continuous but rather retiform contexture and so by such as love hard words or terms of Art may be called after the same name of that Membrane investing the crystalline Humour of the Eye Arachnoeides The Advantages accrueing to the whole through such a disposition of this part as hath already been observed are very considerable inasmuch as that thereby first of all it becomes not only an Integument of inclosure on behalf of the Brain and the Blood-vessels belonging to it in general but of expansion for Strength too where the peculiar structure of Parts in such places as were before mentioned require it As to the first the Brain is not only kept more warm close and compact and better defended on its depending part from the asperity of the Bone it lies upon but the Vessels hereby more strongly supported and it self secured from being broken or torn whilst between its duplicature they climb up into the Brain whose delicate tender Fibres must otherwise of necessity have suffer'd violence by the largeness and pulsation of the Arteries together with the weight of them and the other reductory Vessel from which the Sinus's meet them Nextly as it is an Integument of Expansion in the places before mention'd that tender small part the Infundibulum where it quits the Brain in order to its passage into the Glandula Pituitaria by the circumtension of this outward Lamina is fortified upon any violent Accident from disruption and the Brain and Medulla Oblongata in those places where they are only loosely contiguous are better preserved in their natural due connexion all which Advantages inasmuch as they may more reasonably be ascribed to one double Membrane than two single ones tho' of the like strength when joyned fast together may not unreasonably be thought to argue for the duplicature of this Membrane exclusively to the introduction of a third or new one Lastly as to what concerns the Glandes and Plexus's which Dr. Willis affirms to be scatter'd all over this Membrane as to the former Will. p. 26. col 1. I could never see them but I have seen the external Superficies of the cortical part of the Brain in strangled Bodies appear glandulous very plainly through this transparent Integument which upon bare inspection without further enquiry might easily impose upon the less cautious Spectator As to the latter the Plexus's and distribution of Blood-vessels from them after a separation of the serous gross part of the Blood in the aforementioned supposed Glandules according to that learned person's conjecture into the substance of the Brain in order to produce the finer Animal Spirits I cannot but look upon it altogether conjectural till such time as not only the Glandes but their excretory Ducts also together with the Emunctories where the supposed excrementitious Juice is eliminated lymphatick or reductory Glandes if they could be found never having been by Nature designed to any such use be first discovered Blood-vessels
dispersed thro' Bourd p. 196. par 2. it so forcible as to create a sensible Systole and Diastole in its outward coverings 'T is worth noting that while the Blood-vessels are all full so as to keep the Dura Mater upon its full stretch the pulsation is not vi sible at all or at least very faintly but after a depletion of the Vessels so as that grows somewhat more lax the beating becomes very visible equally in the Sinus and Membrane too After having made this Experiment I found one Author of the same opinion and that is Falloppius who in vindication of Galen against Vesalius his Contemporary says all I have said upon the foregoing Experiment and all the great Vesalius was able to answer in his own vindication in his ingenious Book call'd Anatomicam Gabr. Falloppi Observat Examen falls very short of its aim As to the Transverse Ligaments which are in some places * Fig. 4. r. round cordal and in others †Ibid. x. broad or membranous in the Longitudinal Sinus chiefly both serving for Strength and in concurrence with the cruciform ligamentous Fibres taken notice of by Vieussenius on the under and outside of this Sinus from whence the Fibres belonging to the falcated Process aforemention'd seem to have their original Elasticity to this part for its more vigorous reduction of the Blood passing through it together with its blind Cavities or Diverticulums serving to moderate the over-swift or violent motion of the Blood seeing I find them so exactly describ'd by Vieussenius to whom the Reader may have recourse I think their description need take up no room here But as to the manner of the Veins entring this Sinus I find it far different from that which is describ'd by Lower first Low fig. 4. h h. Vituss tab 2 D D c. and afterwards by Vieussenius both whom make them enter with their Orifices from behind forwards two or three only excepted by Vieussenius and that for some other useful purposes than what have hitherto been taken notice of And this is as follows Fig. 4. dd c. viz. About one half of them tho' intermixedly but all after having first upon their arival at the Sinus insinuated themselves for some space alter the manner of the Pancreatick Duct or Ureters first taken notice of by Lower Ib. dd c. betwixt the Duplicature of the Dura Mater from behind forwards the other half from before backwards as in the Figure Now by this contrivance 't is plain that first of all there are made two contrary Torrents in one and the same Channel by which means the refluent Blood made poor by the vast quantity of its richest parts drawn off as it were into Animal Spirits thro' a collision of Parts which by this contrivance must needs fall out is preserv'd in its due mixture which when at any time lost through the languishing of its intestine motion or elasticity retards even its circular or progressive motion which when it happens but in some degree is the cause of many Distempers and when altogether of Death it self In the next place the circulation is at all times not only somewhat retarded and the Blood hinder'd together with the help of the bony Cell at which the internal Jugular Veins enter the Sinus's especially in an erect posture from descending with that rapidness and weight it would otherwise have done upon the descending Cava to the Heart but also much more so retarded in a supine position of the Head a posture most natural and ordinary for Mankind to take their rest in through which contrivance in concurrence with that of the Lateral Sinus's whose structure is such that in the aforesaid posture the Blood is forced to climb upwards before it can arrive at the place of its descent into the Jugular Vein there is made a more plentiful generation of Animal Spirits one chief Cause of the great refreshment and vigorous disposition of the whole Body we find after Sleeping As to the other manner of the Veins entring this Sinus viz. from before backwards it from thence happens that in a prone Position of the Brain a posture not uncommon amongst Men the Blood is help'd forward in its circulation through the Sinus the truth and design whereof are at once both evident and pointed at by Nature from the Structure of this part and which therefore shews the great usefulness of Comparative Anatomy in Brutes who by reason of such a Position which the necessity of Feeding almost always keeps them in have always such a disposition of this Part to assist the Blood in its heavy circulation The design of Nature in making these Channels so wide on a sudden in respect to the Branches of Veins lately treated of terminating in them seems to correspond with the conformation of the Parts just now treated of and with that it had in making the Ramifications of Arteries afore taken notice of so large and unproportionable to the Trunks from which they spring which is a flower than ordinary circulation of Blood through the Brain in order to make a still more copious production of the Animal Spirits so called Which profitable Design and End of Nature had nevertheless been attended with a very great Inconvenience viz. an extravasation of too much Serum the usual effect or consequence of a slacken'd Circulation had it not been for another provident Contrivance of Nature in the two Communicant-branches betwixt the Carotid and Vertebral Arteries aforemention'd p. 36. by the narrowness of whose Channel the influent Blood is in some measure represt in its motion and an overcharging the Vessels with Blood prevented These Sinus's differ in structure one from another the Longitudinal and Lateral ones having many transverse Ligaments which the other have not and the Longitudinal having many small Cavities or blind Diverticulums as aforesaid which the Lateral have not the use of them all being for strengthening and defending them from giving way to the violent irruption of Blood into them against which sometimes notwithstanding they are not able to defend themselves as I have seen in many Skulls ni which the Blood hath burst open the sides of the Sinus's and found its way between the Duplicature of it so as even to have made a Fovea or Cavity in the Cranium it self as was before noted one of which I have now by me CHAP. VII Of the Plexus Choroeides THIS Plexus is an aggregate Body made up of Arteries Veins Membrane and Glands double on each side which hath not before been taken notice of and consequently having two Originals The first Original is from the foremost Branch of the Communicant Artery FIG 1. ee which running backward up betwixt the hinder Lobes of the Brain in which for some part of the way it is immerged and to which it gives many large Branches and the Medulla Oblongata at length arrives at the Lateral Ventricles FIG 5. ee and makes one part of
Tunnel as well as by reason also of the parity of their Uses the Ancients gave the Name of Infundibulum In Man it is closely inverted with the Pia Mater at its very entrance into the Gland and from that place hath not any manifest Cavity I could discover by blast or style but is altogether of a medullary substance contrary to what it is in Sheep or Calves in which last Creature where the Parts are larger by inserting a Blow-pipe into that part of the Infundibulum next to the Gland I have seen its further Tract or Passage on the upper part thereof a little puffed up and a considerable quantity of Water regurgitate as though it had lain contain'd either in some Pipes or Porulous Substance of that Gland This Difference is not take notice of by Vieussenius and therefore what he says of this part seems chiefly in this respect if not altogether applicable to the Structure it hath in Men. Those two Divisions or Ramifications of this part the said Author mentions Vieussen p. 49. par 3. one forwardly and the other backwardly in Sheep Calves c. I have always found correspondent to the Descriptions he there gives of them but whether the first be protended so and terminate after the manner he there describes I somewhat scruple seeing I have always observ'd the Extremity of that part in Brutes towards the foremost part of the Gland sinking as it were into the very Substance thereof and afterwards becoming presently altogether imperceptible and in Man the termination thereof just after the same manner save only that in the last it happen forthwith upon its approach to the Gland without being protended either backwardly or forwardly The Use of this part is certainly to convey some sort of Humidity from that great concamerated Cavity within the Brain resulting from its inward complication of parts to the Pituitary Gland and the office of it is to receive and carry off this transmitted Humidity but as to how either this Humidity is collected in the aforesaid Cavity or how when convey'd into the Gland it is carried off we are still as much in the dark as ever I know very well there is nothing more easie with the Visionary Philosophers than such a Knack as this and now I think on 't the great Willis makes nothing of turning a Vein into a Lymphoeduct in the Glandula Pinealis and Plexus Choroeides Will. p. 46. no less than which does also the accurate Vieussenius Vieus p. 110 par 3. in the Plexus belonging to the fourth Ventricle but how consonant this is to the rational structure or mechanism of parts neither the one or the other have been so kind as to explain Now as to the Plexus and Glands before mention'd 't is evident by what hath been already discover'd and accordingly given an account of in the preceding Pages they are furnish'd with Lymphoeducts as proper reductory Vessels so that so far the Prophecy is vanish'd But as to the remaining Gland I am not so fond of guessing to say it hath any and consequently all I can say is that as I look upon the Infundibulum to be no more than a large Lymphoeduct variously ramified through the Glandula Pituitaria discharging its Liquor by those many small Branches into the Veins dispersed through that part to be reduced after the manner 't is in all other Secretory Glands back to the Blood gain And that which seems most to favour this Conjecture is the extraordinary humidity of this Gland especially in Brutes above the rest of the whole Body as serving not only to export what Lympha is separated from several Arteries dispersed thro' it but that also which it is charged with from the Brain it self And to this twofold manner or double office of Secretion is owing the two distinct Substances it seems to consist of the one being accommodated to that part of the Lympha coming from the Brain and is therefore whitish the other to that separated immediately out of the Blood and is therefore reddish Lastly As to the manner how the Lympha passes down thro' the Infundibulum passes down thro' the Infundibulum from the Brain to the Glandula Pituitaria I look upon it to be in the form of condensed Vapours arising from the Arteries of the Plexus Choroeides emitted thence for the keeping moist and in good order that inward Production of the Pia Mater spread all over its Parietes which being a membranous dry part of it self might otherwise become injurious to that fine medullary part lying under and being contiguous to it in which there is a continual motion of Animal Spirits whose Tracts and consequently they themselves through any the least intemperance of this Membrane would be in great danger of either some obstruction or disorder And that this Lympha is only the result of the aforesaid Vapours I am the more readily enclin'd to believe because I never saw Water in that part of any sound Brain nor unsound neither where the Plexus Choroeides was firm and there was no reasonable ground by the extravasation of Serum in some other remote parts of the Brain to believe it had its rise from thence CHAP. X. Of the Glandula Pinealis THE Gland call'd Pinealis from its Figure is about the bigness of an ordinary Pea prefix'd to the two Prominencies call'd Nates hereafter to be describ'd at the end of the third Ventricle immediately under the broad and hinder part of the Fornix with which nevertheless it hath no connexion Vieuss p. 71. as Vieussenius saith it hath and over that part of the Rima in the third Ventricle call'd Anus 'T is joyn'd to the Nates by several Fibrous Roots and becomes a support to that part of the Plexus Choroeides there situate In an hydropical Brain of a strumous Boy I have seen it swelled to a size of three times its ordinary magnitude and by reason of the abundance of stagnate gelatinous Lympha contain'd in it perfectly transparent Hence it most plainly appears that this part is a meer Gland and by what was said before conformable to what hath been observ'd in this hydropick Brain of the Conglobate or Lymphatick kind and by consequence a very unfit part to be made a Receptacle of Animal Spirits Vieus p. 71. as Vieussenius makes it and much more a place of residence for the Soul according to Des Chartes 'T is true there are two fair medullary Tracts arising seemingly from the two Roots of the Fornix stretching length-way upon the Thalami Nervorum Opticorum as far back as this Gland by Vieussenius called as this Gland Vieuss p. 6â— par 3. by Vieussenius called Tractatus Medullaris Nervorum opticorum Thalamis interjectus as though it was only one and accordingly is so delineated by him Tab. 7. GG but indeed is two one on each side about which place they turn in and by a transverse bending kind of a Process by the same
Author call'd Tractus medullaris natibus antepositus unite as he hath exactly observ'd Willis p. 9. col 1. par 1. And this doubtless gave occasion to the Error of Des Chartes as Willis truly thought whose sublime and most deservedly-admir'd Philosophy had doubtless been much more useful had he convers'd more with Dissections and less with Invisibility and Vieussenius too Mural p. 508. Will. p. 10. col 1. par 3 with whom in the same Mistake doth agree Muraltus and Willis for upon a more heedful inspection as was most evident in the Brain aforemention'd it will be found that no part of the Process aforesaid however near it comes to this Gland does in any wise become continuous to it Dr. Wharton also stumbled upon these medullary Tracts Whart p. 141. placing them amongst the Nerves themselves and ascribes the same unreasonable use to them as he does to the Nerves in many other Parts of the body viz. of separating a superfluous Humour from the Cruca Medulla Oblongata or Thalami Nervorum Opticorum being the same Part and only on the other side or upper part of the Brain under another denomination which he supposes to be the Commune Sensorium It hath Arteries and Veins in common with other Glands the Veins ending in the fourth or inward Sinus as may the Lymphaeducts too when they are conspicuous CHAP. XI Of the Brain in general THAT part of this Treatise relating to the Vessels being dispatch'd I shall in the next place proceed to an account of the Brain it self under which term are generally comprehended the Cerebrum and Cerebellum and Medulla Oblongata which Parts being in many respects so different one from another may justly challenge a distinct and orderly description The Brain then in the first place as distinct from the other two is that large and almost spherical Body which comes first to sight in the old way of Dissection filling the greatest part of all that space contain'd in the Cranium consisting of two different Substances first taken notice of by Archangelus Piccolominius both in Colour Consistence Piccolom p. 252. and Office the one being more compact white medullary or fibrous the other softer greyish and glandulous The utmost Malpighius by vertue of his Microscopes could do Malp. De Cereb Cort. p. 78 81. par 3. was to discover the Cortical part to consist of Glands of an oval depressed Figure and in his Opinion of the Conglomerate kind but that how properly as also his calling the Nerves their Excretory Ducts I leave to the Judgment of others and the Medullary part to consist of various Fibres immerged in and having their original from the aforesaid Glands deriving from them a certain Liquor call'd Nervous Juice concerning the Existence of which in the usual sence 't is taken in as a fluid body contain'd and running continually in the Channel of the Nerves as Water in Wooden or Leaden Pipes for either Nutrition or Censation is a thing somewhat improbable it being not only possible but very easie to resolve those two Phoenomena's the first from the Blood and the other from the Natural Tenseness of Sensible Parts maintain'd by the supply of a proper Liquor from the Blood both in their Originals and continued or elongated Productions inasmuch as it doth as certainly circulate in them as in any other parts of the Body And as to the manner how this is done it will appear very plain and intelligible after the innate Structure of the Part hath been more accurately enquired into The Curious Lewenhoeck made a far deeper scrutiny into these two Parts Lawenh de Struct Cereb p. 37. being very probably assisted by better Glasses and from what occurr'd to his view called the cortical part a pellucid Vitrious Oily Substance the seeming oiliness of which Substance I attribute only to the stagnating of the pure Liquor growing cold after death of the Creature from such a close and regular Position of the Globuli swimming therein as allows the Rays of Light to pass them without refraction contrary to what they do in the other or medullary part of the Brain in which they are so dispos'd that the Light cannot pass them in right lines and consequently being a little distorted makes them appear white notwithstanding Malpighius on the contrary neither allows the Parts of the Brain to be diaphanous Malpig de Cereb p. â— nor the Animal Spirits to be any thing a-kin to Light 'T is true even by his own confession that his most nice and diligent Inspections could not free him from many Scruples about what he saw yet some things to our purpose were plain enough as Reticular Bodies of a red colour which being larger in the Cortical Parts than Medullary helps to give it that greyish or subrunneous colour as he calls it Nextly a transparent Vitrouscolour'd Substance contain'd in most minute Vessels whence 't is plain there are two sorts of Liquors in this Cortical Part one of a red colour or Blood contain'd in larger Vessels whose Globuli which give it its redness either by reason of their size or figure cannot enter those small Vessels which with the Fluid contained in them constitute this transparent cineritious or cortical part of the Brain The other a transparent Liquor contained in most minute Vessels as aforemention'd from whence I am induced to believe this Cortical part to be only an Aggregate of different Vessels as also I do of all the rest of the Parts of the Body containing different sorts of Fluids Of these Vessels some contain a more compound Liquor commonly call'd Blood which whilst in that state by reason of the Globuli swimming on it looks red and by reason of a tubulous Pore of a proper size and figure so continued to the Vessel we call a Vein that it undergoes a continual quick circulation Another sort of Vessels there is which receive and contain a more simple fluid body of a thin transparent nature which when in some parts of the Body gives the name of Lymphaeducts to the Vessels that it runs in but when in these Vessels which are discover'd to make up the great Substance of the Brain whether Cortical or Medullary may be allow'd the name of Fluidum Animale And this last sort of Vessels I look upon to be either a certain Protension of an Artery by its smallness render'd capable of holding such a sort of Liquor only as the last spoken of or else such a tubulous production of the Artery as by its Orifice of Pore answers to the figure and size of the Fluid it is by Nature intended to receive Upon the same exact Enquiry made by a Microscope the medullary part of the Brain appears to be of the very same constitutive parts ranged only after a somewhat different manner which makes this part appear more white as was before observ'd But over-and-above if it may be allowable to make a Conjecture I am enclin'd to think the Whiteness
to make inflation an Error incident to the Immortal Borellus also Borel de mot Atiâ— p. ult prep 23. â—â—ribus â—lâ—s lociâ— whose imaginary Discourse upon this Subject seems of a very different Thread from the rest of his Excellent Works If therefore what hath been already said about the Structure of Parts be remembred viz. That the Medullary Part of the Brain is only a Contexture of Vessels that its Nervous Propagation or Nerve is also a Compages of Vessels formerly call'd Filaments much more narrow than those of the Brain it self and that these Nerves produce or at least terminate in the Fibres of all sorts of sensible Parts whatsoever though of a different texture as well as those carnous ones of Muscles which last are tubulous 't will not be in the least unreasonable to inferr That these Bodies being kept continually turgid with the contained Fluid are equally capable of transmitting or receiving Impressions of the Object as if they were stretched longitudinally like a Bow-string from each Extremity according as Borellus hath observed And as to Muscular Motion allowing only what may directly be inferred from what hath previously been said viz. That the Nervous and Carnous Fibres are only a congeries of Fluids contained in certain Vessels communicating with each other that by reason of a Plenitude in the aforesaid Fibres the whole Machine is in a constant Equilibrium it will necessarily follow upon the common Postulatum to which all Mankind must be beholdden upon all such Explications as these to the World's end viz. that the Sensative or Rational Soul can command the Animal Spirits which I call only a Nervous Fluid into a Primus Impetus or local motion that a part of that Liquor whenever a Muscle contracted is transmitted through the Vessels which contain it from the great Reservatory thereof the Brain to its Carnous Fibres into whose Vessels being so much narrower than those of the Nerves even by vertue of the same force which moves it from the Brain that Liquor is driven after a most rapid manner which Effect to any acquainted with the nature of Fluids and mechanical Laws of Motion by Projection needs not any demonstration causing the Intumescence or Inflation of the Muscle the same Liquor at the same time being driven back again with an equal speed from the Antagonist Muscle into the room of the first which was transmitted from the Brain to the contracted one in order to maintain the same Plenitude or which is the same thing in the sence of the old Philosophers to avoid a Vacuum And if any object the wideness of the Passage it is to come back by from the reflexed Muscle as an impediment to an equivalent speed in that Liquors retrocession I have to answer that the Emptiness being made first is a sufficient recompence for that And here I cannot but take notice that all they who contend for Animal Spirits analogous to those we see produc'd from various Subjects by Fire as the only adequate medium for all sorts of Muscular Motion have been forced to have recourse either to certain Tracts or Interstices betwixt the Filaments of the Nerves continued from the Brain or the Original of the Nerves through their whole Productions to the Muscle of which sort are the Cartesians or else to a certain Nervous Juice for their place of residence of which sort are most of the Moderns and particularly Vieussenius by which Passages or out of which Juice these fine invisible things are either voluntarily by the command of the Soul or inadvertently from several either inward or outward impressions transmitted in order to produce Motion which if true and the only ways of producing Muscular Motion I beg leave to ask how it comes to pass by either of these ways that when another person bends my Arm and that againfl my Will too the bending Muscles of the Arm become as tumid as when voluntarily or inadvertently contracted at any other time which hath been truly observ'd tho' not satisfactorily accounted for by Dr. Croone Croone p. â—â— or any other I know of But how this or any other sort of contraction of a Muscle happens does by the other afore-mention'd Hypothesis become explicable without any manner of difficulty at all For when the Cause of Contraction is from the Command of the Soul the pressure is first from the Fluid in the Brain by which all the interjacent or continued Fluid slows towards the Part to be moved the same proportion of Fluid being at the same instant transferred into its room from the relaxed Muscle and when the contraction of the Muscle is from the above-mention'd external force bending the Arm against my will then the Liquor contained in the relaxed carnous Fibres or Vascula is transmitted through the whole continuity of Fluids to that which is contracted and all this without being beholden to the wild Conceits of a dry and moist part of the Nervous Juice blind Passages invisible Tubuli betwixt the Antagonist Muscles or Valves in the Nerves by a meer Aequilibrium of the Fluids contained in the Vessels the Parts consist of At the same time I am not insensible of the Solution some have given this Instance of Involuntary Motion upon another Hypothesis viz. by supposing an equality of Tension or Elasticity in all the Muscles of the whole Body by which means it falls out that when any new additional force though never so small is added to the Fibres of any Muscle as in voluntary motion or the power of Elasticity in the Antagonist Muscle overcome by outward force as in the aforemention'd Instance of Involuntary Motion the other Muscle then becomes contracted Now that this is one concurrent Cause in both sorts of Instances as being confirm'd by the Experiment of cutting a Muscle through either towards the Extreams or in the middle by which the Fibres by their natural Elasticity are found to contract either to one or the other or to both Extreams is allow'd to be true but to be the only Cause is altogether as false For in the first place as to the case of voluntary Contractions it is allow'd to proceed from a transmission of Spirits from the Brain into the carnous Fibres that Hypothesis of Steno to the contrary having been convicted long since by Borellus in his Book De Motu Animalium though not without the concurrence or sympraxis of the natural Elasticity of the Fibres belonging to the Muscle to be contracted So likewise without the transmission of Animal Spirits from some force or another I deny even the possibility of that stiffness or hardness which is easily preserved in all contracted Muscles feeling and seeming as though they were indurated and swelled out as really they are whether it be in the case of voluntary or involudtary motion in confirmation of which I affirm that though by the cutting of the carnous Fibres of any Muscle through which way soever it be the contracted part
both of that Membrane and the Blood-vessels themselves 'T is also imperfectly divided thro' all its external cortical part by the Pia Mater though not so profoundly to the end the Blood-vessels may penetrate this part in more sine and reticular Ramifications and that by the pulsation of the Arteries the interjacent cortical Glands or rather Vessels may more freely make their proper Secretions Nextly it may be consider'd in its inward appearance which is concave and medullary taking its original from the Extremities or Apices of the Medulla Oblongata or rather a little more forwardly from the foremost part of Vieussenius's oval Center commonly called Processus Lentiformes or according to Dr. Willis Corpora Striata From hence 't is presently reflected back on each side in the form of a Vault very near as far as the Nates and Testes a little below which on each side 't is joyn'd with the Crura Medulla Oblongata on their under side being continuous there to those Parts commonly call'd the Crura Fornicis The middle and uppermost part of this Medullary Substance by the Ancients always called Corpus Callosum is therefore by Vieussenius called Fornix Vera Vicus p 61 par 1. in his Opinion sustaining that Office though I see not that it does or for the Reasons before given in the description of the Dura Mater and ' its Processes needs to do any such thing This is that part which as was before noted was thought but mistakenly by Vesalius and others to escape the covering of the Pia Mater and in it are not visible any bloody Specks as in most other parts of the Medulla Cerebri 'T is the medium uniting the medullary part of each Hemisphere or Division of the Brain famous for the transverse Stria running through it from each side of the aforesaid Hemispheres the Septum Lucidum only coming between In this large or principal Cavity are contained the three Ventricles the Fornix the Septum Lucidum Corpora Striata Thalami Nervorum Opticorum the Roots of the Fornix the Tractus Intermedius of the Corpora Striata the Tractus Medullaris Thalamis Nervorum Opticorum Interjectus which last has bin already described the Vulva Anus and Rima or Passage to the Glandula Pituitaria by the Infundibulum and Glandula Pinealis which also hath already been described of all which briefly in their order The three Ventricles FIG 5. AA by cutting asunder the Fornix near to its Roots and turning it backwards over the Nates The three Ventricles Testes and Glandula Pinealis appear to be but one those on each side it being called the Laterales in which are the Corpora Striata Thalami Nervorum Opticorum and Crura Medulla Oblongata that Rima so far as 't is covered with the Fornix and parts the Crura Medulla Oblongata being the third From the extream Limits of these two side Ventricles Vieuss T. 10 AA c. from before to behind Centrum Ovale does arise that medullary space called by Vieussenius Centrum Ovale in his Opinion the great Dispensatory of Animal Spirits the fore part whereof Willis calls Limbus anterior corporis striati Will. De An. Bâ—ut p 42. T. 8. F. The Fornix is a medullary part arising from two Roots in the foremost part of the Basis of the Brain The Forix FIG 5. AA bb lying betwixt and upon the uppermost parts of the Thalami Nervorum Opticorum which Roots come out of the foremost part of the Geminum Centrum semicirculari so called by Vieussenius like two large Nerves and afterwards joyn together constituting a broadish medullary Body which after having first projected it self for some space forwardly betwixt the Corpora Striata and afterwards run the length of the third Ventricle growing all the way broader and broader and towards its edges by Vieussenius called Fimbrae thinner Viâ—ussu Tab 6. D and being reflected backward towards the hinder part of the lateral Ventricles like two Arms commonly called Crura Fornicis the beginnings whereof on each side are by Aurantius called Hippocampi and Bombyces Auraâ— Anal. Oâ— p. 45. from whence I know he had chiefly observ'd this part in Brutes in which by vertue of the hinder part of the Fornix in that place growing somewhat thicker and running over the hinder and upper parts of the Th. Nerv Opticorum which are more prominent in them as in Sheep Calves c. than in Men it is made to appear on each side like the bending Crest of the Sea-horse and is in colour much like the Silk-worm certain minute Stria's Malp. de Câ—râ—b p. 5. which Malpighius calls Fibrae crossing them like Rings obliquely contrary to what the same Author's Account is of them who says those Fibrae or Striae run upon them otherwise viz. as they do on the Septum Lucidum i. e. longitudinally and embracing the Th. Ner. Opt. on their upper part on both sides but adhering close to them as one continued Substance on their under part in which place they are called by Vieussenius Vieus p 61. Posteriores veri fornicis viz. Corporis Callosi Columnae becomes there continuous with the hinder part of the Corpus Callosum where it winds down upon the sides of the Crura Medulla Oblongata Ibid. and makes up that undermost space or cavity of the two side Ventricles by the said Aurantius called Ventriculi Hippocampi or Bombycini and Vieussenius called the hinder part of the Centrum Ovale which by that kind of curved passage loses something of its oval figure The Septum Lucidum The Septum Lucidum some of the Moderns think to arise from the Fornix thence ascending to the internal Superficies of the Corpus Callosum others from this last descending down to the Fornix but most likely from this last where towards its foremost part I have always sound it double first taken notice of by Sylvius de le Boe and as Vieussenius truly says Sylv. dele Boe Disp Med. p. 19. par 1. Thes 13. often with Water in its duplicature 'T is a very thin medullary transparent Body intermediate to the Corpus Callosum and subjacent Fornix by means whereof the two lateral Ventricles are in that place separated one from another The Corpora Striata The Corpora Striata FIG 5. I 1 c. or Processus Lentiformes are two Prominencies situated something higher than and in Men a great part of them on each side though Dr. Willis says where the Corpora Striata ends the Thalami Nervorum Opticorum begins which is only so in Brutes of the Thalami Nervorum Opticorum or Juga Crurum Medullae Oblongatae and are so called from the many white Streaks appearing in them descending obliquely to the Medulla Oblongata with Cineritious Substance coming betwixt them when they are cut horizontally They run down on each side the Thalami Nervorum Opticorum as far as till the Corpus Callosum begins to wind back
upon the Crura Medulla Oblongata towards the hindermost part thereof I have got them delineated here exactly true tho' by neglect without the Striae finding all the Cuts of them in Willis to be from Brutes except one which is done very ill and those in Vieussenius very false unless in Figure the 8th which also wants the Striae The Thalami Nervorum Opticorum The Thalami Nervorum Opticorum are two prominent Bodies more purely medullary on their outward Superficies than within which meeting together like the two topmost stroaks of a Y inverted constitute the uppermost part only of the Crura Medulla Oblongata in that form the other or undermost side being quite of another figure and seeing they are the immediate continued Productions of the Medulla Globosa Cerebri which contrary to the old Opinion of Praxagoras and Philotimus asserting the Brain to be only a Germination of the Dorsal Marrow of late reviv'd by Bartholine Causab â—n Athan. p. 137. if any precedency of Parts as to time may be allow'd I look upon to be rather the original than the production of the Medulla Oblongata and Spinalis too and may more properly be called Capita than Crura of the Medulla Oblongata The Tops or Juga do FIG 5. cc. as already observed encline close yea joyn together as Vieussenius hath rightly observed contrary to Willis whose Figures of that part are utterly false unless where the Rima ad Infundibulum parts them leaving like the Corpora Striata an obtuse angle between them Betwixt these two last mention'd Bodies there is a medullary space on each side which in a bending manner encompasses the Thalami themselves and receive the Extremities of the Striae in the Corpora Striata as they descend from the aforemention'd Centrum Ovale and is therefore by Vieussenius called Geminum Centrum Semicirculare Vieus p. 67. par 2. Willis de An. Brut. p. 42. T. 8. 〈◊〉 by Willis Limbi Posteriores Corporum Striatorum The reason why they are called Thalami Nervorum Opticorum is from certain Fibres supposed to be in them arising both from their true medullary Superficies by Vieussenius call'd a Medullary Membrane and some from within their own Substance which at last towards their foremost part meeting together make up the Bodies of the Optick Nerves Willis says nothing of these Fibres though in his Opinion Galen did not improperly give them that name Vieussenius paints them very strong As for my part I never could find any Fibres at all appearing in their external medullary part those within are very small at best and scarce discernable On the outside of these I have always found and often showed a very fair medullary Tract A Medullaâ—y Tract Tab. 5. mm here described running all-along betwixt the Corpora Striata c from the very hindermost extent of the Corpora Striata forwardly down to the very Roots of the Fornix to which they seem to be continuous The Passage into the Infundibulum Within this Cavity of the Brain are likewise two passages into the Infundibulum and so on to the Glandula Pituitaria the foremost of which is called by the odd Name of Vulva The Vulva and the hindermost of Anus The Anus from their situation which with the Rima betwixt them is called as was before noted the third Ventricle The places whence all this Water issues are commonly by the latter Anatomists described under the name of Tria Foramina Tria Foramina situated so as to give passage from all the eminent Regions of the Brain from whence there can be access had to them for the Water or rather the Lympha properly so called to fall into the aforesaid Infundibulum the first whereof is behind the Testes under the Valvula major hereafter to be described the other just under the Pineal Gland or the beginning of the Rima which two meet in an Aperture under the Nates and Testes Vieus p. 73. par 3. by Vieussenius call'd Aquae Emissarium having a steep descent into the Infundibulum and the last at the end of the Rima or just under the Roots of the Fornix and all ending at length tho' by two different passages in the Infundibulum It may not be unseasonable in the next place to take notice of two remarkable very fair Processes The Nates and Testes Tab. 7. CC called Nates and Testes by former Anatomists so named from the resemblance they had to those parts but it is plain from thence they were only used to dissect Brutes in which they have such a proportion as is betwixt them whereas in Men 't is plain they are very near of the same size and not very different in form being oblong and accuminated towards their Extremities but in Sheep Calves and most other Creatures the Nates are round and large and the Testes oblong somewhat accuminated and very small Before these Natiform Processes under the Glandula Pinealis runs a transverse Process before taken notice of Pag. 84 Vieussen Tab. 8. f by Vieussenius called Processus Natibus Antepositus and Nervuli Aemulus which upon further enquiry by drawing the Thalami Nervorum Opticorum still wider appears to be rather Nervi than Nervuli Aemulus being as thick as that behind the Roots of the Fornix to which in situation 't is just opposite and seems to joyn the Thalami Nervorum Opticorum together as that does the Corpora Striata In what rank to place them 't is hard to say as being neither proper Appendices to either the Brain or Cerebellum properly so called and being divided from the Medulla Oblongata in some measure by an Interstice commonly called Ductus ad Infundibulum by the Moderns but by the Ancients a Passage for the Animal Spirits to the fourth or noble Ventricle They are situated upon that part of the Medulla Oblongata which is between the Cerebrum and Cerebellum The Isthmus which space was before called Isthmus opposite to that part called from its Author Pons Varolii and by many Authors as Bartholine Spigelius Highmore c. thought to be the two hindermost Roots of the Spinalis Medulla which much more likely Riolanus makes the Processes of the Cerebellum to be Visalius p. 766 767. fig. 10. AA I K. fig. 11. GG and with him the great Vesalius who paints them so From this intermediate situation Dr. Willis thought sit to make them as it were an Intelligence Office betwixt the Cerebrum and Cerebellum how rightly I refer to the Judgment of others 'T is certain they are medullary Bodies and contribute to the making the Animal Fluid or Spirits so called after the same manner as the rest of the Brain does for in cutting them through after having taken the reticular expansion of Blood-vessels off from them which is very large here and eminently conspicuous in injected Brains I find them of the very same substance with the Processus
Annular Process running down upon the Med. Oblongata the space of an inch ending a good space below the place where the Eighth Pair of Nerves begin which have their original between the Corpora Olivaria and the Chordal Processes partly on the other side thereof contrary to the account we have of them by Dr. Willis Willis p. 13. col 1. par 1 p. 61. col 2. par 3. who describes them as ending in pointed Extremities just where those Nerves have their original On each side of these appear plainly the Corpora Olivaria The Corpara Olivaria Iâ—â—d o. so called from their Figure as the former were by Vieussenius which with the Corpora Pyramidalia and two white Bodies behind the Infundibulum he calls Conceptacula Spirituum Animalium or places containing Animal Spirits upon several occasions of use to the Brain both in its natural and intellectual Faculties CHAP. XVI Of the Nerves IN the same position of the Brain we also have a sit time of taking a view of the Nerves which are still medullary Productions of the Brain dispersed to all the parts of the Body which have need of either Sense or Motion and these are in number ten Pairs or Conjugations having their Names and Originals as follows The first is the Olfactory Pair which after they leave the former Lobes of the Brain and begin to run to the Bone called Ethmoides take the name of Processus Mammillares but this is chiefly in Brutes where through their largeness they have that appearance and are manifestly hollow By the utmost Scrutiny I have been able to make they have but one Original and that is from the undermost and foremost part of the Crura Medulla Oblongata where they advance on each side into the Globous medullary part of the Brain from whence running concealed betwixt its foremost and hinder Lobes obliquely for a good space at last they come in sight as you see them in the Figure And by what means Vieussenius comes to find such diffused Originals for them as he speaks of I know not Their Use is known to most and a particular account thereof as of the rest together with the manner of Sensation with relation to the external Organs of Sense is much more fit for a Physiological Tract than one of this kind I shall therefore only at this time give a general description of the Nerves belonging to the Brain how and where they arise the difference or variety whereof serve very well to inform us according to several late Theories concerning the different Reservatories of the Animal Fluid or Spirits and the different dispensation of the same to several parts of the Body The second Pair are called the Optick or Seeing Nerves The Second Pair Ibid. 2 2. of which I sind no more Originals than of the former and that is from those medullary parts called Thalami Nervorum Opticorum tho' Vieussenius says they are from several parts and Willis in general terms from the aforesaid Thalami Nervorum Opticorum behind the Corpora Striata which description is more exact in Quadrupeds where the Thalami Nervorum Opticorum are altogether in situation behind the Corpora Striata than in Men where a great part of the Corpora Striata are situated on the outsides of the Thalami Nervorum Opticorum and only their Heads or Extremities before them The Blood vessels mention'd both by Willis and Vieussenius belonging to these Nerves I have seen to run not only upon or with them but also in injected Bodies exactly quite thro' the medullary substance of them into the reticular Coat of the Eye wherein they end in an infinite number of the most capillary Ramifications which by an injection of that Artery made with Mercury become very delightfully conspicuous to the Eye The Nervous Fibres also from the fifth and third Pair of Nerves do twine about the Bodies of these Nerves as the two above-mention'd Authors do truly affirm but how rightly they both assign to them the office of dilating and contracting them subserviently to the visory faculty and preternaturally in Convulsions of the Eye as though these Fibres were truly Muscles or of the carnous kind I refer to the Judgment of others These go out of the Skull at its first Foramen The third Pair arise out of the forward and upper part of the Annular Process where 't is contiguous to and covered with the under part of the Thalami Nervorum Opticorum coming out into sight from between them just where that Process terminates forwardly which is where the Crura Medulla Oblongata come together into one body constituting the Caudex Medulloe Oblongatoe These running through a duplicature of the Dura Mater on the outside of the Circular Sinus go out of the second hole of the Skull to the Eyes and are therefore called Par Oculorum Motorium to the voluntary motion of which only they are granted to be subservient which seeing they have their original from the Cerebellum afford us no weak Argument against the Hypothesis of Dr. Willis who hath reserv'd that part in Nerves subservient to involuntary motions only The fourth Pair is very small The Fourth Pair Ibid 4 4. coming from the transverse Process on the foreside of the Medulla Oblongata behind the Testes first coming in sight between the undermost part of the hinder Lobe of the Brain and the Cerebellum laterally crossing that part where the Annular Process ends towards the Crura Medulla Oblongata from whence they pass into a duplicature of the Dura Mater and afterwards a little more outwardly than the former goes through the same second hole to the Trochlear Muscle of the Eye and are called from their moving of that according to the passions of the Mind the Pathetick Pair The fifth Pair is broad and large The Fifth Pair â—ld 5 5. made up of many thick Fibres continuous to each other some softer than others arising from the uppermost part of the Processus Annularis which is backward laterally where 't is broadest by reason of the second Process of the Cerebellum there entering it This Nerve The several â—â—â—ches of the fifth Pair after having first climb'd over the inner Process of the Os Petrosum into a kind of a Cavity made of a duplicature of the Dura Mater in that place immediately swells into a kind of a thickness called a Ganglion Pro. 3. B from whence several Branches are propagated lying betwixt the Dura Mater and the Cranium on each side the Sella Turcica without any Fovea or Cavity at all going out of the Skull at three several place Pro. 3. C D E its superiour small Branch at the second hole with the third and fourth Pair of Nerves its inferiour smaller Branch at the third hole and its posteriour or largest Branch at the fifth From the inside of the foremost Branch two little ones turn back FIG 2. y. and meeting with another small Branch a little
the Tubulus Venosus between the Sinus of the Porta and the Cava in the Liver as hath been most sagaciously observ'd by the late Learned Dr. Walter Needham 'T is true That in several Creatures there are some Nerves very much depending on the Cerebellum as are they which minister though in a different manner as hath already been taken notice of and will be hereafter further explained to the Natural and Vital Functions viz. the Par Vagum and Intercostal Pairs and therefore the aforesaid Author who is in this as in many other of his Discoveries very fortunate and highly commendable made a very good guess when he brought these Faculties into subjection to that part inasmuch as by several others as well as by my own Experience upon living Bodies we find that notwithstanding most part of the Brain be pared off with a Razor yea even after the Medulla Oblongata be divided betwixt the Cerebum and Cerebellum and taken wholly out of the Cranium the Heart will beat when at the same time if the Cerebellum it self be but cut in pieces though all the rest of the Brain be kept entire the Creature expires presently Yea I have seen Respiration which only in part depends on the Cerebellum totally to cease upon only a sudden violent compression of that part by a blow and after its being wounded the Heart to cease beating immediately All which must of natural consequence fall out upon the Hypothesis That those Functions of Nature do depend on the Cerebellum for their source and influence which is constant uninterrupted and out of the arbitrary jurisdiction of the Brain yet with this difference that in Motions purely natural and either contemporary with the Embrio as the first signs of its vitality such as is Pulsation of the Heart during its enclosure within the Mother or supervenient upon its further growth and more visible organisation of Parts as the natural contraction of the other Viscera subservient to the offices of Protrusion of the Chyle separation of the Glandular Juices and proscription of the Excrements the Animal Fluid or Spirits do altogether flow from the Cerebellum the Nerves there both descending from the Cerebellum and terminating in those parts afore-mentioned whereas in Respiration which I call a Motion of Supervenient Instinct if I may be allowed to use the word Instinct in that sence the Nerves descending from the Cerebellum and propagated through the Lungs from the Par Vagum serve only to convey the first Impulse or Impression of the Object to those parts which are by Nature framed and qualified to produce Respiratory Motion and those are the Nerves of the Spinal Marrow receiving the impression from the Cerebellum seeing that by the aforesaid Experiment it appears plain that after the whole Cerebrum was divided from the Cerebellum and Medulla Oblongata the act of Respiration continued for a considerable time entrire which Motion is dependent on the Sensative Faculty presiding in the Cerebellum transmitting the first Impulse produced by the eighth Pair or ParVagum as before observ'd and communicated thence to those Spinal Nerves which act the Intercostal Muscles and Diaphragm So that all the office of the Par Vagum which is propagated thro' the Lungs is to convey the Impression from thence to the Cerebellum which by vertue of its connexion with the Caudex Medullaris from whence the Ancients rightly thought that part had its hindermost Roots from the Cerebellum as before taken notice of it is able to transmit it further as the Sensative Faculty presiding there shall direct and that too by the common way the Medulla Oblongata and Spinal Nerves And further That this part is as capable thereof as the Cerebrum and is not wholly and only deputed for the service of such Nerves or Organs as are employed by the involuntary part or portion of the Soul as Dr. Willis would have it appears in that the third Pair of Nerves by him allowed to be amongst the number of the other kind of Nerves viz. those commanded by the Will from hence as hath been already shewn hath its original And here also furthermore give me leave to add by way of conjecture that the reason why the Soul hath not an equal command over those afore mention'd Nerves dedicated to the vital and natural Motions is the early date or commencement of the office of those Nerves by which means they contract an habitual irresistible Influx much less so in those belonging to the Respiratory Functions the exercise whereof is of a later date and lastly the Influx is not in the least so habitual in those other subservient to the Organical Functions of the Limbs inasmuch as they are not capable of being exercised till a much longer time after and then not so uninterruptedly as either the first or the second but gradually and with intermissions So that the only reason why upon cutting the Cerebellum Respiration ceases is that by that means its structure is discomposed and render'd unfit either to receive or transmit the impression further to the aforesaid Nerves which are subservient to the Instruments of Respiration 'T is true there arc reciprocal communications betwixt the Nerves of the Intercostal Pair Vertebrae and Diaphragm yet seeing they terminate nor immediately in the Parts of each others particular distinct jurisdictions there is no interchangeable act or office from thence produced betwixt them For as notwithstanding there are so many Branches of Nerves communicated from the Spinal Nerves subservient to voluntary motion to the Intercostal Pair on their descent to the Viscera and yet by reason of their not terminating in those parts they are not in the least able to bring these Nerves under the commands of the Rational Soul by which provident Care of Nature it so falls out that 't is not in the power of any by misguided Reason to act injuriously to themselves So by vertue of several Branches reciprocally communicated from the Intercostal Pair in its passage down to the Viscera to the Spinal Nerves there is no power given to them of moving the Muscles to which they are subservient uninterruptedly after the meer manner of the Viscera But now to return to where we left off in some Creatures it 's very plain that Nature hath extended this imperial residence of the Soul beyond the Cerebellum even as far as the Spinalis Medulla having not only put this last motion but that of Pulsation too under the jurisdiction of that elongation of the Brain as appears in the famous Experiment of the Industrious Caldesi upon the Tortoise which after the Head was cut off lived and carried its Shell about the space of six Months Besides which 't is remarkable by way of digression according to another Experiment by the aforesaid Author made upon that Creature that after even the Heart and all the Viscera besides were taken out except the Lungs that Creature to use his own Expression was sound so to
and Vieussenius the one placing the Commune Sensorium in his Corpora Striata only the other in the superiour and middle Corpora Striata jointly with the Centrum Ovale from both whom Des Cartes and several others and with much more shew of Reason particularly Malpighius differ Malpig de Cereb p 11. par 2. placing it in the extream limits of the medullary part of the Brain where 't is continuous with the cineritious circumassused Part I must confess that as I have not been able by the best enquiry I could make either into Brains dissected whilst fresh or when boiled in Oyl to discover any such actual configuration or disposition of Parts as we find so formally delineated by either of them but especially the last So neither do I see any necessity thereof seeing we may much more easily and to the self-same ends and advantages look upon the Soul as one internal principal Sensative Faculty and the whole medullary part of the Brain as consisting of such Fibrils or Vascula's as in some places more nearly in others more remotely communicate with the Nerves propagated thence to all the external Sensories one adequate Common Sensory by which that principal Faculty both receives all its impressions and accordingly as by so many gradations of one and the same power executes or performs those different Functions commonly going under the aforesaid Names of The Common Sense or Simple Apprehension Imagination Judgment and Memory And as to the second viz. the Medullary Tracts by which the Animal Fluid as by so many Rivulets is derived from the great Pond or Magazine into many Rivers furnishing the whole Body therewith all I could find by the most diligent search were only those which have already in the preceding Sheets been remark'd of which in the first place are those in the Corpora Striata very large and discernable Those in the inward or concave Superficies of the Corpus Callosum running transversely by the Septum Lucidum into the Fornix and from that longitudinally into its hinder Thighs or Pillars formerly called Bombyces over which they run in a wreathed manner as was before observed terminating in the back part of the Lateral Ventricles enclosed in the hinder Limbs of the Brain which Ventricles at length terminate in and are continuous to the subjacent fore-part of the Crura Medulla Oblongata Those in the Thalami Nervorum Opticorum running obliquely down to part of the subjacent Crura and Caudex Medullaris Those of the Nates and Testes running after the same manner and terminating so too only something lower Those in the Annulary Process which forasmuch as they have never before been taken notice of I have caused to be engraved in a Figure by themselves whose Medullary Tracts or Striae furnished with Spirits both from the continuous medullary Caudex and Productions of the Cerebellum too of which the Annular Process is made by means whereof the Nerves appertaining thereto may be rationally supposed to be under the influence of both those Parts conformable to what hath all-along been asserted are as visible being more thick and of a far harder consistence than that of the Corpora Striata themselves tho' upon every attempt of cutting that Process they may not appear so and most of them terminating in a middle Medullary Tract by means whereof there is the same inconveniency prevented at least in some measure as there is by that sepimentum of the Pia Mater continued from the joyning together of the Crura Medulla Oblongata down quite thro' the Medulla Spinalis viz. that at the same time the Nerves on one side may as Molinetti Mol. p. 104 tho' in another place of the Brain hath truly observed by any morbid cause be injured those on the other may escape Concerning these seeing they seem to have a particular aspect or relation to those Nerves whose originals we find nearest them it may not be unreasonable to think they are particular Conduits from whence the said Nerves are furnished with Animal Fluid though at the same time we must allow a very free communication betwixt them all And consequently we may suppose the first of those to convey Spirits from the globous medullary part of the Brain next to it by Vienssenius called the Superiouâ— Part of the Centrum Ovale down to the subjacent medullary part of the Brain to augment those which are produced lower and particularly for the service of the Olfactory and Visory Nerves which last hath more eminently its Supply from the Thalami Nervorum Opticorum The second sort or the transverse Striae's of the Corpus Callosum to convey an additional Supplement by way of the wreathed Tracts in the hinder Columns of the Fornix to the Crura Medulla Oblongata where they become continuous to the reflex'd part of the Lateral Ventricles backwardly for the service also of the aforesaid two Pair of Nerves but more particularly to those arising lower either on the Annular Process or Caudex Medullaris Those of the Thalami Nervorum Opticorum and Natiform Processes the first of which lies upon and is continuous to the subjacent medullary part of the Crura Medulla Oblongata the other to the Caudex Medullaris may be supposed to derive Spirits on the behalf of those Nerves which spring from any adjacent parts whether on this or the other side of the Annular Process or Caudex Medullaris And of this sort are the Optick Nerves which are supplied immediately from the first of those Medullary Prominencies and not unlikely from those fair Medullary Tracts afore-mentioned running from the Root of the Fornix extending themselves all the way between the Corpora Striata and Thalami Nervorum Opticorum in which last at length they are obliterate The Third Fifth Sixth and First or hard Branch of the Auditory Nerves mediately by continuity of them with the Annular Protuberance to all which the other or lesser Medullary Prominencies called Nates by vertue of their continuity with the subjacent parts may be supposed to contribute something also and these seems to be better provided for than the rest of the Nerves inasmuch as besides this way of being supplied from the Cerebrum they have also another very visible and much larger from the Second Process of the Cerebellum of which the Annular Protuberance is made and this seemingly not without a provident Design of Nature seeing the Nerves which are derived thence are much larger and have a greater Task of service layed upon them than any others of the whole Brain as hath also the Par Vagum or eighth Pair which therefore by vertue of its insertion between the Chordal or third Process of the Cerebellum and Corpus Olivare and not according to Dr. Willis from the points or extremities of the Corpora Pyramidalia hath a double tribute of Spirits one from the Caudex Medullaris or Cerebrum the other from the Cerebellum And to this End or great Service it looks as though this
Process was furnished with such a Texture as it appears to have of strong large medullary Striae's capable of receiving and containing a Supply from both Fountains Whence it may not be unseasonable to remark That not without shew of good Reason I have all-along asserted the Propriety of the Brain to those Nerves in part allowed by Dr. Willis to be no further affected by any Impressions of the Brain than as first conveyed from it into the Province of the Cerebellum and consequently to depend immediately on this last for influence entirely in order to convey Animal Spirits to those parts wherein they are inserted Upon the Caudex Medullaris on its under side contiguous to the hinder Extremities of the Annular Process are situate the Corpora Pyramidalia and Olivaria over-against which are the two long Medullary Tracts lately taken notice of seeming to come from the transverse Medullary Process behind the Testes and terminating in those other transverse Medullary Processes before the entrance into the Fourth Ventricle on the other side by which there may be conveyed a considerable Portion of the Animal Fluid to the Pathetick Nerve which hath its rise from the first transverse Process and to the soft or second Branch of the Auditory Nerve which hath its rise from the second on that side and also to the Ninth and Tenth Pair on the other side And to conclude From all these taken together with the rest of the whole medullary part of the Brain the Overplus of what is not spent upon the inmate Nerves of the Brain may truly be supposed to be promiscuously dispensed to all those other extraneous ones produced from the elongation of the Brain call'd the Spinal Marrow In which last there is this conformation or disposition of Parts differing from that of the Brain that whereas in that the cineritious part is external 't is here internal and this for very good reason and by a provident contrivance of Nature seeing that not only the cineritious part of the Brain serves for supplying those Nerves which have their original thence as well as all the rest of the Spinal Marrow and consequently ought to have the largest space and dimensions possible which without this situation could not have been but also without this contrivance the Nerves of this part must of necessity have had their originals from the cineritious part of the aforesaid Marrow contrary to both the custom and convenience of Nature too FIG I. Exhibits the Basis of the Brain with part of the Medulla Oblongata the Blood-vessels being injected with Wax A A The fore Lobes of the Brain B B The hinder Lobes CC The Cerebellum D D The lateral Sinus's E E The Vertebral Arteries as they pass between the first Vertebra and the Bone of the Occiput F The Vertebral Sinus G c The Dura Mater on the right side taken off from the Spinal Marrow and remaining on the left 1 2 3 4 c. The ten pair of Nerves belonging to the Brain with seven of the Spinal Marrow a The Foramen that opens into the Pituitary Gland from the Infundibulum b b The two white Protuberances behind the Infundibulum c c The two Trunks of the Carotid Artery cut off where they begin to run betwixt the fore and hinder Lobes of the Brain d d The two Arteries joyning the Carotids with the Cervical Artery called the Communicant Branches e e Two large Branches of the Cervical Artery sometimes seeming as tho' they came from the Communicant Branch on each side from the first of which the Plexus Chorocides hath its original in chief and from the last the Plexus Chorocides of the 4th Ventricle f Several little Branches arising from the Carotid Artery g The Cervical Artery composed of the two Trunks of the Vertebral Artery within the Cranium h h The two Trunks of the Vertebral Artery i i i The Spinal Artery k A small Branch of an Artery running through the 9th pair broken off from its other part thro' inadvertency of the Graver l l The Crura of the Medulla Oblongata m m The Annular Protuberance or Pons Varolii n That part of the Caudex Medullaris on the right side called by Willis and Vieussenius Corpora Pyramidalia o That part on the same side called Corpus Olivare p The foremost Branch of the Carotid Artery dividing the fore Lobes of the Brain consisting of two Branches one of them only appearing here q q Little Branches of Arteries helping to make the Plexus chorocides in the 4th Ventricle r r r Branches of Arteries dispersed from the Cervical Artery upon and thro' the Annular Protuberance s s Part of the 2d Process or Podunculi of the Cerebellum ** The Spinal Accessory Nerve FIG II. Shewing the internal Basis of the Cranium the Sinus's being injected with Wax A A The Edges of the Skull B B The Dura Mater upon the bottom of the Skull C C The lateral Sinus's d d The superiour longer and narrower Sinus's e e The inferiour shorter and wider Sinus's f The Process of the Bone Cribriforme called Crista Galli g g Some small descending Branches of Veins upon the bottom of the Dura Mater h h The first Branch of Arteries proper to the D. Mater i i The second Branch of Arteries belonging to the Dura Mater k The third Branch belonging to the Dura Mater L The last hole of the Skull m m Several Veins communicating with the inferiour short Sinus's n Part of the Os Jugale o o The Os Ethmoeid where the first pair of Nerves or mammillary Processes go forth p p The Optick Nerves cut off q q The Carotid Arteries cut off r The third pair of Nerves vissible only on one side S S The fourth pair of Nerves turned up t t The fifth pair of Nerves on one side expanded before it is divided into its three Branches on the other side whole which Nerves with its three Branches are expressed in the third Figure V It s foremost superiour Branch on the left side going out at the second hole of the Skull w The sixth pair of Nerves X The Intercostal Nerves in this subject proceeding from two Branches of the fifth Nerve joyning with the body of the sixth Nerve y Two Branches of the fifth pair of Nerves in this subject running almost close to the 6th pair being partly the Roots of the Intercostal Nerve which creeps out of the Skull under and between the Coats of the Carotid Artery z z The Body of the Carotid Artery after it has entred the Cranium 1 1 The Glandula Pituitaria 2 2 The Circular Sinus 3 The Infundibulum 4 4 The Frontal Arteries 5 The place where the Lateral Sinus's begin to be declive and tortuous 6 The Dura Mater raised and reclined to shew the subjacent Nerves 7 7 The seventh or Auditory Nerves 8 8 The eighth pair or Par Vagum 9 9 The ninth pair FIG III. Being the Fifth Nerve with its Branches whilst within the Cranium
A It s Trunk B It s Ganglion C It s first or superiour Branch going out at the second hole of the Cranium D Its second or midle Branch going out at the second hole E Its third or hindermost Branch going out at the fifth hole FIG IV. Shews the superiour and lateral Sinus's of the Dura Mater opened after they had been injected with Wax A A The third or longitudinal Sinus B B The first and second or lateral Sinus's C The fourth Sinus d d d A Vein running on each side of the third Sinus eeee Mouths of Veins opening into the longitudinal Sinus of the Dura Mater after a contrary manner one to the other f f The fifth Sinus at the bottom of the Falx g The Torcular where all the superiour and lateral Sinus's meet h h The tortuous part of the lateral Sinus running under the Cerebellum i i The Veins entering the fourth Sinus from the Plexus Choroeides k The place where the fourth Sinus arises ** The Specus or round hole at which the lateral Sinus's on each side go out into the internal Jugular Vein l l Two large Veins whereof one enters the fourth Sinus upon the second Process of the Dura Mater so as to resist the course of the Blood in that Sinus in its ascent to the Torcular the other upon the same Process so as to hinder its descent to the Internal Jugular contrary to a conformation of Vessels which Vieussenius mentions in his third Table H H. mmm Transverse Chordal Ligaments in the longitudinal and lateral Sinus's n n Part of the Dura Mater on each side of the longitudinal Sinus o o Portions of the Pia Mater PP c Divers small Veins on the Dura Mater which enter those that run on the sides of the longitudinal Sinus according to its length qq c The Veins of the Cerebrum as they appear under the Pia Mater before they enter the longitudinal Sinus R R The falcated Process with its Veins which enter the fifth Sinus S S The second Process of the Dura Mater ††The beginnings of the Jugular Veins FIG V. Representing the Brain in a middle section the Blood-vessels being first injected with Wax A A The Fornix cut off at its Roots and turned back b b Its Roots at the beginning of the Thalami Nervorum Opticorum cc c. The Thalami Nervorum Opticorum d d That part of the Crura Fornicis which growing somewhat thicker as it turns off towards the Lateral Ventricles runs over the Crura Medulla Oblongata which being very prominent in Sheep and Calves helps to thrust it up into such a Protuberance as the Ancients called Bombyces or Hyppocampi e e That part of the Plexus Choroeides which is made of the first Branch of the Cervical Artery sometimes seeming as tho it came from the Communicant Branch in the Lateral Ventricles f The place where those two Plexus's on each side meet under the Fornix g g That other part of the Plexus which is made of the second Branch of the Cervical Artery joyned with the first by a Communicant Branch not to be seen here lying under the Crura Fornicis which is expanded all over the Isthmus becoming glandulous near to and especially under the â—â—aâ—dâ—la Pinealis covered here with the Fornix h h Two large Veins coming from the top of the upper part of the Plexus down to the other Branch of the Plexus all the length of the third Ventricle and then terminates in the the fourth Sinus i i The Trunks of several Arteries appearing as they were cut off in dividing the Medullary †and Cineritious * part of the Brain k k A Venous Branch of each side entring the Plexus Choroeides from whence there are many slips branched upon the Corpora Striata Δ Δ The Corpora Striata whole l The Rima of the third Ventricle m m A long Medullary Tract between the Thalami Nervorum Opticorum and Corpora Striata nn c. The Centrum Ovale of Vieussenius O The fourth Sinus of the Dur. Mater P The Torcular where the four and sometimes five Sinus's meet Q Q The Lateral Sinus's R A large Vein entering the Lat. Sinus's on one side SS c. The Cerebellum covered with the second Process of the Dura Mater on its uppermost part T T The Vertebral Arteries V V the Vertebral Sinus's W The Medulla Spinalis with its integuments x x The Style supporting the large Veins of the Plexus Choroeides in the third Ventricle q q The Lymphaeducts of the Plexus Choroeides Y Y Two of the Cervical Nerves springing from the Medulla Oblongata ††c. The Medullary part of the Brain ** c. The Cineritious part FIG VI. Being a draught of the Annular Protuberance Med. Spinalis c. cut through the middle lengthway A A The Crura Medulla Oblongata B B The Annular Process or Pons Varolii divided c c The Transverse Striae e e The intervening Medullary Tract in which the Striae terminates on each side f f The third or chordal Process of Dr. Willis h The Spinal Marrow i i Some part of the Cerebellum k k The second Processes of the Cerebellum which compose the Annular Protuberance l l The cineritious part of the Medulla Oblongata FIG VII Being the Cerebellum cut through on its hinder part and reclined laterally A A The Cerebellum B B The arboreous ramification of the Meditallium of the Cerebellum appearing being cut right downwards C C The Pathetick Nerves c c The Nates d d The Testes e The transverse Process whence the Pathetick Pair have their original f The Glandula Pinealis g g The first Process of the Cerebellum running from it to the Nates here extended laterally h h The third or Chordal Processes i i The transverse medullary Process in the 4 Vent from whence the soft Branch of the 7 N. has it original k k The Medullary Process descending from the Transverse Process behind the Testes down to the aforemention'd other Medullary Transverse Process l l The Originals of that Process a little too low m m The eighth pair of Nerves n The Calamus Script or Extremity of the 4th Ventricle o The Spinal Marrow P P The Accessory Nerves q q The tenth pair of Nerves THE TABLE A ARtery Carotid and the manner of its entrance into and distribution through the Brain Page 32 33. Where it parts with its borrowed Coat p. 33 Artery Vertebral and its manner of entrance and distribution p. 35 Artery Cervical ibid. Why not Conical p. 38 The Communicant Branches of Arteries p. 36 Their Vse and Benefit ibid. 37 A small Branch of Arteries not before observed p. 38 Why the Arteries of the Brain enter not the Cranium with the Veins p. 27 Artery Spinal how the Blood is forced into it p. 37 Animal Spirits how more plentifully produced p. 54 Anatomy Comparative its use p. 54 Arteries why their Ramifications are over-proportionable to the Trunks in the Brain p. 55 The Vse of the narrowness of the Communicant branches p. 56 How the Carotid Artery in Brutes comes to be smaller above the Dura Mater than under it p. 65 Animal Fluid what p. 91 108 155 How it passes out of the Carnous Fibres p. 109 Its effect in glandulous and other parts not
Arteries unless the Arteries they accompany discharge their Blood into the Sinusses which as hereafter shall be shown they plainly do not for otherwise seeing they both grow capillary in their ascent from the Basis of the Cranium they must necessarily be both adductory Vessels than which by the Laws of Circulation there can be no greater an Absurdity Wepfer not knowing of these Veins was forced to think and consequently to affirm That the Arteries leave the Dura Mater in their extremities and terminate in the Pia Mater and so have their Blood reduced by the Veins there but this is evidently not so to the Eye of any who heedfully separates this Membrane from the other Before therefore I proceed to the description of the Blood-vessels belonging to the Brain it self which by the exactness of method I ought to do I hope it may be pardonable if I make a short enquiry after the unaccustom'd distribution of Blood-vessels Nature hath furnish'd the Brain in general with and the Reasons of its procedure therein The Truth then concerning this affair is That contrary to what hath hitherto been observed the Blood-vessels belonging to this part in general as hath already been observed are of two sorts the one belonging to the Brain it self the other to its outmost Integuments Now as to the first 't is observable that the Veins enter not the Brain nor run concomitantly like as in other parts of the Body with the Arteries the carotid entring at the fourth hole in the Basis of the Skull and the internal Jugular at the eighth the Vertebral Artery at the last and largest hole of the Skull and the Vertebral Vein at the ninth which Vieussenius mistakenly calls the tenth thro' which it runs into the internal Jugular Vieâ—ssen p. 163. par 3. at that Veins entrance into the round hole at the bottom of the Skull under the Styliform Process where the Sinus Lateralis meets it where after having advanc'd into certain venous productions called Sinus's they descend from thence in large Trunks growing capillary all-along in their passage till they meet the Extremities of the Arteries and are indeed no other than meer Branches of the Sinus's and consequently I look upon the Sinus's themselves no other than large Veins The common reason all modern Authors give for this different distribution of Blood-vessels belonging to the Brain from the other parts of the Body is that it may receive an equal warmth at the top as at the bottom as being thereby very much assisted in the production of Animal Spirits in an equal proportion all over and that it is so may very well be granted but that Nature had yet another provident Intention will be as evident if we consider that if the Veins had ascended with the Arteries thro' the holes in the bottom of the Cranium upon all great Ebulitions of the Blood the pulsation of the Arteries would in that Stricture of the Vessels made by the Bone of necessity hinder the freedom of its return by the Veins and consequently occasion a stagnation of Blood through the whole Brain to the utter subversion of all its faculties nothing being more certain than that upon any considerable abatement of circulation there presently happens by way of restagnation a secession of the watery and thin from the more gross and red part of the Blood The other way of the Veins entring the Brain viz. those appertaining to its outward Integument one at the sixth hole of the Basis of the Cranium the other at the eighth as aforesaid is their ascent with the Arteries after a quite different manner from the former even to their capillary Extremities a manifest indication that they serve for the reduction of so much Blood from the Dura Mater as the aforesaid sort of Vessels the Arteries have brought thither and although by reason of their smallness Nature seems not to have been so sollicitous in avoiding the Inconvenience supposed to have follow'd upon the Artery's entring the same hole with the Veins taken notice of in the preceding Case where they are very large and consequently the Effect might prove much more injurious yet Nature hath not been wanting in providing a Remedy against it as will plainly appear in the following Pages From this manner of their entring the Brain at the same inlet of the Skull with the Arteries may for ought I know be very rationally accounted for that violent troublesome Noise which many in Distempers arising from the turgescency of the Blood causing a preternatural beating of the Arteries do so much complain of a Symptom happening from the Stricture before mention'd which the unyielding circumference of the Bone occasions upon the different Blood-vessels entring at one and the same Foramen to which effect also the nearness of the Os Petrosum through which the Hearing Nerves do pass to this hole which is in that part of the Wedglike Bone that joyns to or is conterminous with it does not a little contribute To the same cause in some measure doubtless may be ascribed the frequent Headachs happening in Feavers the Artery then so swelling and compressing the Vein against the edges of the Bone that the Blood cannot be returned back through it in a due proportion and consequently by its stagnation the Membrane becomes inflamed and painful So that conformable to what hath already been taken notice of concerning the wise contrivance of Nature in ordering the different distribution of the Blood-vessels so as to avoid the Inconveniencies which might accrew to the Brain by compression of the reductory Vessels occasion'd through their entrance at one and the same hole with the Arteries it seems very much worth our observing that besides the Veins of the Dura Mater which enter the Cranium together with the Arteries as hath before been mention'd there are also several others belonging to this Membrane having their rise at and their descent after a very remarkable manner from a Vein hereafter to be describ'd on each side of the Longitudinal Sinus as you may see in the Figure FIG 4. dd nn c. and consequently must grow capillary in their descent down from it after a quite contrary manner to the other and these do visibly inosculate with some of the Extremities of the aforesaid capillary Arteries after the same manner as those larger Veins belonging to the Pia Mater do with the Arteries belonging to the Brain and it by which means it so falls out that a considerable part of that Blood brought up by the Meninx Arteries is carried back by these Veins to the end that especially in all preternatural swelling of the Blood the inconvenience of Compression and all its ill consequences happening by reason of an overfulness of these Vessels may be in a great measure avoided CHAP. IV. Of the Veins belonging to the Brain it self AFTER this short digression by order of Method the Blood-vessels belonging properly to the Brain it self fall under consideration The curious
the Plexus on each side The second Original is from the hindermost Branch of that Communicant Artery FIG 1. second ee which running more backwardly ascends betwixt the hinder Limbs of the Brain and the Cerebellum till it comes to the Isthmus where communicating with the first Branch abovemention'd they make a reticular broad Expansion which covers both Nates Testes and Glandula Pinealis FIG 5. GG and constitutes the second or other part of the Plexus Choroeides The first Branch begins to divide it self into divers Network Fouldings interspersed with Glands somewhat what before it enters the Ventricles Ibid. 5. and continues such to its Extremity on each side where they both under the Fornix wind cross the third Ventricle into a mutual inosculation The second begins to assume the same shape or contexture as soon as it begins to enter the Isthmus continuing such throughout its entire abovemention'd Expansion These two on each side are joined together by a twofold connexion the first is by an Artery running under the Bombyces intervening betwixt them which could not be here inserted so as to come in view The second is by a production of the Pia Mater which is extended all over these parts of the Lateral Ventricles and the third Ventricle which lyes betwixt the first two parts of the Plexus forwardly and down to the other two hinder parts of the Plexus backwardly under the Fornix and Septum Lucidum so that whatsoever Water is transmitted out of these Ventricles must slip down not only under the Fornix but that Membranous Production it self from which kind of structure and position of this Membrane may probably be understood how there might happen such an Hydrocephalus as the learned Tulpius mentions Tulp lib. 1. cap. 24 in which there was found above two pounds of Water in one Ventricle without any at all in the other and such another as Wepfer mentions Wepf. p. 69 where the Water causing the Hydrocephalus in an Heifer was found contain'd in a Cystis and that only in the left Ventricle too for supposing this membranous production of the Pia Mater to be double here as it certainly is in all other places 't is not difficult to conceive that the Water which is extravasated must needs insinuate it self betwixt the two Lamina's till by a continual encrease it extends them into the shape of a large Bladder such a one as the latter found there and drew out with his Fingers and that which seems to put out of all Controversie that it was so is that in those places both above towards the Corpus Callosum and below on the Basis of the Ventricle he found some sort of Asperities as though the Bladder fill'd with Water had been covered with some small Protuberances not much unlike to White Poppy-seed in those places where it was contiguous to them which Protuberances doubtless were the small Glands interspersed quite through this Plexus How this Distemper came to be on one side only though sometimes it is on both as you may see in another place of the aforesaid Tulpius may likely enough be from an Adnascency of both the Lamina's of this Membranous Production Willis p. 10 col 2. par 1. in that place where the Septum Lucidum sinks down from the Fornix occasion'd by some small sort of pressure of the superincumbent Brain Besides these Veins which are very truly describ'd by Willis I have always found two more meeting the foremost Extremities of this Plexus from between the two first Lobes of the Brain where it seems to end under the foremost part of the Corpora Striata by which it is there fixed and as it were kept in its due situation and from these Branches are on each side sent forth many more little ones to the Corpora Striata and several other parts adjacent To this Plexus belong also Veins which from the Extremities of that part of it in the Lateral Ventricles begin to come into two distinct pretty large Trunks FIG 5. hh running down thro' the middle of the third Ventricle as far as the fourth Sinus and there receiving some Branches from the other hinder part of the Plexus spread over the Isthmus discharge the refluent Blood into that Sinus But besides this sort of Reductory Vessels Ibid. qq it hath also another viz. Lymphaeducts which I first discover'd in the Brain of a strangled Body and shew'd to several then present running in different ramisications amongst the reticulated Vessels and Glands of this part Which Observation being added to that of the great Anatomist Anthony Nuck who in that curious Piece call'd Adenogrophia says Nuc. p. 150. he saw one coming from the Glandula Pinealis and that his Friend another Anatomist whose Name he mentions not but I know it was one Bodivol whom I had the Happiness to be very well acquainted withal now dead sent him word he saw another not far from the aforesaid place may be of sufficient authority to evince the real Existence of these Vessels hitherto so much enquir'd after in the Brain as well as in other parts of the Body The Glands belonging to this Plexus are very many but very small and their Use according to all the Moderns especially Willis Duncan and Vieussenius to carry off the redundant watery part of the Blood but that without ever shewing by what rational contrivance of Structure it can be done seeing none of them ascribe a Secretory Duct which must always be in readiness when any unprofitable part is to be discharg'd Since therefore this part is found furnish'd with Lymphaeducts 't will be no hard matter to conceive the genuine use of the Glands which is to separate a rich nutritious Juice from the influent Blood and by the Lymphaeducts to refund it to the refluent after the loss of its noblest parts left behind in the Brain in its passage to the Heart again It may also for ought I know according to the Opinion of Willis serve to warm its neighbouring parts the Internal Superficies of the Brain which being purely medullary hath not so plentiful a share of Blood-vessels dispersed through it as the rest and consequently to maintain an equality of warmth conducing so much to the conserving the Spirits in their due vigour and exercise must borrow an additional supply from hence It is situated upon the middle of the Thalami Nervorum Opticorum all-along them length way and contrary to what Willis says is by vertue of several Blood-vessels join'd to that medullary part of the Brain so call'd immediately lying under it CHAP. VIII Of the Rete Mirabile NOtwithstanding the Opinions of the late Wepfer Willis and Vieussenius too which two last indeed tho' but now and then are willing to allow it an existence only in Men who nevertheless if the Supposition of Willis be true viz. That such cannot but be Fools had better be without it Willis p. 2â— col 2.
together with almost all the Ancients as Vesalius Columbus c. to the contrary I have never found this Rete wanting or with any difficulty discoverable in Men springing from and lying on the inside of each Carotid Artery in that place of the Circular Sinus chiefly which looks into the four abovemention'd inferiour and superiour Sinus's in the Basis of the Brain and in some measure also the whole length of the Sella Turcica on each side between the Gland and the Carotid Artery And that it is so small in them with respect to what it is in Brutes of several kinds is no way surprizing when consideration is had to the Use and Service of it in those Creatures who by reason of their prone Position would otherwise be in danger of having their Brains deluged as it were with an over-great quantity of the Influent Blood and of a Rupture of the Vessels by its violent ingress and this Danger so much the more threatned by how much the same Cause which brings it into the Brain with that force is equally as great and effectual to hinder its proportionable return for the relief of which Inconveniency Nature hath contriv'd a means of its more easie and safe descent into the Brain by turning that one large Stream of Blood which through its being penn'd in one Channel becomes so rapid into many more by which means the Carotid Trunk above the Dura Mater in those Creatures is very small to what it is beneath whereas that Artery in Men c. hath the same bigness on both sides that Membrane and they not only reticulated and contorted for the more slow and laborious which Contrivance the Ancients thought was only for a more exact preparation of the Blood for Animal Spirits descent of the Blood but also many of them by their insertion into the Glandula Pituitaria attended with small Veins issuing thence to take off some part of the burden too This last contrivance of Nature methinks may be sufficient to render that Controversie of Vieussenius with Willis which before them Vieuss p. 16 pat 2. was bewixt Waleus and Rolfincius the two latter on each side denying this Rete to have any Veins very needless feeing that if the Pituitary Gland have any which I am confident it hath notwithstanding the positive Assertion of Diemerbroeke Diemerbr p. 364. par 3. in order to serve his own most unprobable Hypothesis to the contrary as having seen them plain injected with Wax then this part of the Blood in some of the Branches of the said Rete which are plainly inserted into the Gland is equally capable of being reduced by those Veins without any necessity of having recourse to those remote Branches Vieussenius hath been forced to seek for Vieuss p 45 par 2. as if it had had them of its own And that to the aforesaid Position of different Creatures ought chiefly to be ascrib'd the variety of Magnitude of this Rete in several of them its size in Dogs seems highly to evince in which by reason of their Horizontal Position being neither so prone as several Brutes who seed on Grass nor so erect as Man that Rete is found smaller than in the first and larger than in the last Another Use it hath been thought to have is to carry off a considerable quantity of a dull watery part of the Blood in order to the production of the finer Animal Spirits and this it is thought to effect by means and help of the Pituitary Gland betwixt which and it self there is constantly observ'd a greater affinity the one being either greater or lesser in proportion as the other is so and betwixt which there are in all Creatures but more remarkably in those where they are both large a distribution of several Branches coming from the aforesaid Rete And this is look'd upon by Vieussenius so considerable an office of the Glandula Pituitaria that in those Creatures where it is but small as in Men Horses Dogs c. he hath substituted many Vieus p. 102 par 3. but particularly two Cavities for that use in the Wedglike Bone just under the Sella Turcica in which he supposes that part of the aforesaid Serum which by the smallness of the Rete cannot be return'd that way is remitted by several little Arteries slipt off from the Carotid whilst under the Sella Turcica terminating in the two abovenamed Cavities there either deposing a part of the Serum to be carried off by a strange way he there mentions viz. by two holes into the Nostrils and thence into the Fauces or else by certain Veins meeting them in that place as their proper Reductory Vessels Vieuss p. 9. par 2. to the Heart Now as to this office of the Glandula Pituitaria I cannot easily be perswaded it is either design'd for or capable of it till such time the Abettors of this Opinion can be able to show me it furnish'd with an Excretory Duct for this purpose And if they offer that the Veins are such I reply That besides its being very unprobable that so vast a quantity of Blood as continually is brought by the Carotid Arteries to the Brain should be able to get rid of any considerable quantity of its Serosity by so small a part as the Glandula Pituitaria is 't is not the usual way of Nature to part with any Share of its Juices out of its Vessels when so unactive and unprositable as this is and immediately to receive it in again seeing it is provided of Emunctories enough to convey it away by Moreover granting which by no reasonable means is to be granted it were so as they would have it yet nevertheless in conformity to Nature's proceedings in all such-like case there ought to be an intermediate passage by way of a Secretory Duct which none hath been able hitherto to discover And so far as Vieussenius seems to be of this opinion Vieus p. 102 par 3. which in one place he plainly is making it of so gross and viscid a nature as is only sit to be discharg'd at the Emunctory of the Nose the same Reply is satisfactory But when by way of flat contradiction to himself he comes to make the same gross Humour a perfect fine Lympha the Answer is then Vieuss p. 54. par 1. That there is no need of parting with it beforehand seeing we find that Liquor only separated by the Lymphaeducts of the Brain afterwards Seeing therefore there is such an affinity as before mention'd between the Rete Mirabile and Glandula Pituitaria and taking it for granted that the office of the Glandula Pituitaria is not what it hath generally hitherto been believ'd to the end we may attain a more exact knowledge of what it really is it seemeth not altogether immethodical to take that part into consideration in the next place together with the Infundibulum which last hath not only as near a relation to the Gland as the Gland
resist Death as to turn it self from the inverted or supine position it had been placed in in order to make the Experiment to its prone or natural one and to live and move six hours after From whence it appears that Muscular Motion is capable of being performed by the Animal Fluid alone without the concurrence of the Blood by most Authors constantly hitherto made to go a share therewith in the performance of that action Caldesi p. 75 76. So that we find Nature hath not stinted it self to one place for the Seat of the Sensative Soul or Reservatories of the Animal Spirits so called in order to the discharge of the afore-mention'd Functions no more than it is at a loss about the maintaining them in their Integrity by other ways when it hath so fallen out that the natural structure of the Organs destin'd by Nature to that end have utterly been destroy'd of which we have many Instances in the Anatomical History those Functions in several Creatures remaining perfect where after death there have been sound neither any Cerebrum or Cerebellum at all or at least such as by their constitution was utterly render'd useless to any such end Of the first is an Instance of the Learned Wepfer in a Child living sixteen hours alter it was born and discharging all the Duties of Nature that one of its age was capable of and by tho by which all the patrons of a nutritious Juice by the Nerves may do well to take notice of of a very strong and good habit of Body Misc Câ—ries Av. 3 p. 120 whose Brain after death was found to be only an heap of Watery Bladders or Hydatides except a small part at the bottom of the Skull lying in a Sinus made in the Wedglike Bone where the Pituitary Gland is commonly found consisting only of three Medullary Bodies two of which being each of the bigness of a Kidney Bean and the third behind them of a Pea only from which indeed there did proceed some but very inconsiderable Nerves or Nervous Fibrils but such as none can judge of a due proportion requisite to satisfie the Exigencies of the common natural and vital Functions The truth of which is still more plain and without exception in another Instance in the Miscell Med. Physic Gallic of a Child living sive days after it was born Misc Med. Phys Gall. Au. 3. p. 54. whose Head had nothing but Water contained within the inclosures of the Dura and Pia Mater without the least footsteps of any medullary part at all Parallel to which two last Instances I had one communicated to me by that curious Anatomist and learned Person Dr. Tyson in a Child born alive with no more Brain in the Skull than what might lye in a Filbird-shell the Medulla Spinalis being much larger than ordinary as though part of the absent Brain had been squeez'd down thither Of the last viz. where the natural conformation hath been depraved there is extant an Instance in two several places of the Miscell Curios in a sat Ox Misc Cur. Obs 26. 130. An. 1. which while living there were observ'd but very little signs of any such thing whole Brain was nevertheless after death found wholly petrified From all these 't is manifest the Sensative Faculty is able to answer its internal or external Impressions by one part as well as another and that the Medullary System of the Spinalis Medulla may become as adequate a Sensory in relation to the aforesaid Functions sometimes as either Cerebrum or Cerebellum And as to the power or influence the Soul in general exercises over the Nerves howsoever different in their original seeing we have already observed what a provident care Nature hath taken for the preserving Creatures from their own violence in that it hath not only constituted the chief Fountain from whence the great current of Spirits is derived for the service of the vital and natural parts by the Eighth and Intercostal Nerves which is the Cerebellum so as to be free from the commands of the Rational Will in its ordinary way of acting but hath also taken care that not any of those Branches which have their originals from Trunks which are under the power of voluntary dictates of the Soul should terminate in such Organs by which those Functions are discharg'd abare communication between Nerves of different Provinces not being sufficient to such ends or offices as hath been observed in those afore-mention'd additional subsidiary smaller Streams of Spirits flowing to the parts consecrate to the natural and vital Functions by Branches propagated from the Spinal Marrow to the Intercostal Nerve all the way of its descent to the lower Venter So we may further also remark that as there are some manner of Impressions made upon the perceptive Faculty after such sort of a manner as that it even loses its power over its own Subjects viz. the Nerves which are subservient to its voluntary commands as in Laughing Sneezing and libidinous Erections the Organs by which these Actions are produc'd being altogether under the power of those Nerves subservient to the voluntary dictates of the Soul and acted after the very same manner as those of Respiration as often as preportionable objects present and notwithstanding the assertion of Dr. Willis to the contrary who makes Laughing proper to Man only and by the authority of Aristotle Sneezing an Affection proper but to few if any other Creature besides Man might also produce the same effects in Brutes Will p 106 provided their stupid Souls were capable of being equally impressed by such Objects as arc proper for exciting a rational Laughter as we see they are by those producing the aforemention'd venereous actions of the want of the Plexus Cervicalis of the Intercostal Nerves and two or three small Branches propagated from thence to the Nerve of the Diaphragm which he calls a Disposition peculiar to Man and consequently in his opinion the cause of that Affection in him might be in a great measure supplied not only by that nervous Branch we find propagated from the interioâ—r Plexus of the Par Vagum which Nerve is equally dependent on the Cerebellum as the Intercostal to the third Brachial Nerve from which the Nerve of the Diaphragm hath one of its originals but also that other propagated from the Thoracick Plexus of the Intercostal Nerve it self to the same aforesaid Brachial Nerve into which the Nerve of the Diaphragm is inserted So on the contrary there are some Impressions made upon the Soul sometimes through which it acquires a power over those Nerves at other times in no wise subject to it and those are the impressions either of great Joy or great Grief suitable to which the Vital and Natural Faculties are made either much more or else so much less vigorous than ordinary as even quite to languish How this comes to pass according to Dr. Willis in savour of his own Hypothesis and
particularly in relation to the first which allows of no Involuntary Motions but what come from the Province of the Cerebellum is explained by supposing an undulating or rowling motion of the first impression upon the Brain out of it again through the Natiform Processes into the Cerebellum and from thence by the Annular Process into the Intercostal Pair of Nerves and so to the Nerve of the Diaphragm and he should to make this way of explication entire have taken in also all those Vertebral Branches inserted into the Intercostal Nerve in order to the moving of the Intercostal Muscles without which that action cannot be performed by a correspondence between which Nerves and those of the Face being all of one family the aforesaid Gesture of Laughing is performed Now besides the needlesness of bringing the Conceptions or Impressions of the Brain under a necessity of being executed by the inferiour Province of the Cerebellum till such time as 't is proved that such motions of the Spirits upon extraordinary occasions may rationally be granted without supposing a regular motion of the same through such supposed Passages leading from one Part to the other at all other times the allowing whereof does necessarily imply a capacity of the Soul to alter the course of the Spirits influencing the vital and natural Organs at least in some measure at its pleasure which is plainly contrary to Experience I shall hardly look upon that Hypothesis to be any more than meerly precarious And further to shew that such Effects or Alterations of the Vital Organs happening upon violent Passions of the Mind are no way owing to such a transmission of the Animal Fluid from the Cerebrum to the Cerebellum as the aforesaid Author supposeth I ask how it should come to pass that in the contrary Passion of Grief especially when occasion'd by surprizing frightful Accidents the Heart should so languish as sometimes wholly to cease beating seeing in the aforesaid Experiment we find that Motion self-sufficient by vertue of a constant irradiation or influence of the Cerebellum only and consequently could not be thought so to languish upon such occasions for want of those Spirits it never stood in need of Without therefore being forc'd to have recourse to that other Hypothesis clogg'd with so many difficulties I think the aforesaid case may admit of another manner of explication consistent with what I have all-along advanc'd upon this Subject relating to the true source of voluntary and involuntary Actions if we suppose that from such Impressions upon the Soul as are either extreamly more or less welcome to it in which case the Object is said to act unproportionably upon the Subject it may not only act accordingly above its usual irradiation and force over the Cerebellum and by that means as sending the Spirits either more or less copiously to the Vital Organs particularly the Heart the nearest way viz. by the Par Vagum and Intercostal Pair for that time render them more vigorous or more languid in their operations in proportion to the difference of the Passions just after the manner it happens in cases of Alienation of Mind or Distraction where by the Strength of the Impression or Idea upon the Mind it drives the Spirits with such an impetus into the Limbs as makes them act with a vast greater force than what they were wont to do even above the resistance of Chains or Bars of Iron but also it may transmit the Spirits more or less copiously to the Vital and Natural Faculties the other way freed from the subsidiary Nerves of the Spina aforementioned to the Intercostal Pair which sends forth ramifications to the Heart in Men especially equally with if not more plentifully than the Par Vagum and from the Vertebral and Brachial to the Nerve of the Diaphragm and Intercostal Muscles by which means it so falls out upon such impressions that the Organs of Respiration to the sight and that of Pulsation to the touch are very remarkably affected By this means I have endeavour'd to restore the Brain to a capacity of putting its own Conceptions or Impressions made upon it into execution without being beholden to its neighbour the Cerebellum and that either in relation to its voluntary inadvertent or involuntary Acts where note I make a distinction between Acts involuntary and those of inadvertency inasmuch as these last though they are not with yet they are not contrary to the actual consent of the Will after the manner of the natural actions of the Viscera such as are out of the power of the Will to hinder besides which I look upon no other in Rational Creatures in a strict sence consider'd to be involuntary forasmuch as 't is a contradiction to say a Voluntary Agent does any thing against his Rational Will though it may be against his Approbation by which he is only distinguish'd from a Brute Though Dr. Willis hath all-along used the word involuntario in another sence confounding it with acts of meer Ignorance under the term of Insciè and those also done only inadvertently or without consideration under the term of Inconsulto and doubtless upon this notion of Involuntary Motions built his Hypothesis which makes all those Actions which are perform'd at any time without the notice of the Intellectual Faculty notwithstanding at other times they are altogether under its command equally depending on the Cerebellum as those purely natural which are always free from the power of the first and also absolutely subject to the last These Actions I have therefore called by the term of Supervenient Instinct and being the meer Effect of external or internal Impressions upon Sensative Bodies as Ecchoes are to those upon such as are only natural are equally competent to Rational and Irrational Creatures and capable of being exerted by the influence of the very same Nerves which minister to the Sensative Faculty whether it act advertently or inadvertently in the one or spontaneously in the other where by the way it may not be altogether unworthy of our taking notice the genuine sence of that word in Actions performed by those Creatures is much nearer a-kin to the term Inconsulto than Involuntario in Men without the supposed rambling Motions of Impressions made upon it through Passages only at some times or upon eztraordinary occasions made use of out of the Cerebrum into the Cerebellum Now as to the organisation of this Part made to consist of various Medullary Prominencies Appendixes and Tracts by Nature contrived for and adjusted to the various functions of the Soul and dispensation of the Animal Spirits thro' the whole System of the Nerves which first are confin'd to or made to reside in such and such places as so many distinct apartments viz. the Commune Sensorium in one place the Imagination and Judgment in another and the Memory in a third of which there is such a large and formal apparatus and description tho' with great discrepancy of opinion in Willis
sixth pair p. 148 The Intercostal ibid. The seventh or auditory pair p. 149 The eighth or Par Vagum The Accessory Spinal Nerve p. 151 The ninth pair p. 142 The tenth pair p. 153 The structure of the Nerves p. 154 Nerves their different functions p. 157 The effects of Communications betwixt Nerves p. 175 181 The Nerves within the Cranium how supplied with Spirits from various medullary Tracts of the brain p. 194 195 c. O Optick Nerve its original p. 123 External Objects how they act p. 158 Improportionable actings of the Object p. 186 Organization of the brain p. 189 Overplus of the Animal Fluid of Cerebrum with its use p. 199 P The Pia Mater p. 10 Why called Choroeides ibid. It s particular distribution ibid. How to isnd it in the Ventricles p. 11 Is double every where but where most visibly p. 12 It s inward Lamina is of a Netlike Texture p. 15 Its Vses p. 16 Its Blood-vessels which are of two sorts p. 18 19 How it invests the Nerves and their distinct Fibrils p. 19 How the Arteries belonging to the Brain it self are ramified through it p. 33 How some branches of the Carotid and Vertebral Arteries are exempt from it p. 34 The Processes of the Dura Mater with their distribution and use p. 7 8 9 Pulsation of the Sinus's whence p. 50 The Plexus Choroeides of the Brain p. 57 It is double ibid. Hath two different Originals ibid. What they are ibid. Where the first part begins to be glandulous p. 58 Where the first part of the Plexus terminate and meet p. 58 Where the second part begins to be retiform ibid. The double connexion of the two parts of the Plexus ibid. Two Veins joyning the first part of the Plexus in its extremity p. 61 It s large reductory Veins entering the fourth Sinus ibid. Its Lymphaeducts ibid. It s Glands p. 62 Their Vse ibid. 63 Its situation and use ibid. The Pituitary Gland hath Veins p. 66 Processus Lentiformes vid. Corpora Striata Passage into the Infundibulum p. 123 Processus Annularis or second Process of the Cerebellum p. 129 135 140 Its Striae p. 136 Processus Natibus antepositus p. 125 Processus Nervi Aemulus p. 126 Processus Nervuli Aemulus p. 128 The Plexus Choroeides of the Cerebell p. 134 Processus Vermiculares p. 135 The first Process of the Cerebellum ibid. The third or Choadal Process of the Cerebellum p. 136 The medullary transverse Processes of the fourth Ventricle p. 136 The medullary Processes descending to those transverse ones p. 137 The Plexus Choroeides of the Cerebellum p. 133 Perception or Passion what p. 158 R The Receptacula Sellae Aequinae c. of Vieussenius not existent in Men p. 45 Their Vse impossible p. 46 The Rete Mirabile p. 64 Always existent in Men ibid. It s situation ibid. Why smaller in them than Brutes ib. 65 The effect of its being so large in Brutes p. 65 Is differently situated in Men and Brutes p. 72 Hindermost Roots of the Medulla Spinalis what formerly p. 126 Respiration how performed p. 165 Why a Child unborn respires not p. 168 Why Respiration ceases upon cutting the Cerebellum p. 174 S Sinus's of the Brain p. 39 Their number ibid. The Lateral ones p. 40 The third or longitudinal p. 41 The fourth or internal one ibid. Four other smaller Sinus's and their first Author p. 42 43 The Circular Sinus p. 43 It s particular description ibid. 44 Its use p. 47 48 No Serum can be separated but by proper secretory Ducts p. 47 The Sinus's have no pulsation of themselves p. 50 Their pulsation is from the Brain ibid. The different Ligaments of the Sinus's p. 57 The use thereof ibid The blind Cavities or Diverticulums of the Sinus's p. 52 Their Vses ibid. The structure of the Sinus's p. 53 Effects thereof ibid. Animal Spirits how made more plentifully p. 54 Why the Sinus's grow so wide on a sudden ibid Their difference of structure p. 56 The longest Sinus commonly burst in strangled bodies ibid How the blood passes the Lateral Sinus's in different positions of the Brain p. 54 Structure of the Brain Vascular p. 91 Secretion how made p. 91 92 Sensation how explained p. 88 101 How made p. 158 Corpora Striata p. 115 120 Septum Lucidum p. 119 It s Striae ibid. The Spinalis Medulla in a Tortoise officiating instead of the Brain p. 176 Sneezing why peculiar to Man p. 182 Commune Sensorium what p. 191 Striae of the Annular Process why large p. 193 197 Why terminating in a middle medullary Tract p. 193 Conformation of the Spinal Marrow differing from that of the Brain and why p. 200 T Torcular Herophili p. 42 Tractus Medullaris Th. Nerv Opt. interjectus of Vieussenius p. 84 Tract Med. Natibus antepositus of Vieussen ibid. Transpiration what p. 95 Conspiration of Hippocrates ibid Tone of Parts p. 109 Testes p. 125 Thalami Nervorum Opticorum p. 121 Tria Foramina relating to the Insundibulum vide Insundibulum V Vapours commonly so called how sometimes affecting the Fibres of the Dura Mater p. 6 Some Veins of the D. Mater entering the third Sinus p. 41 Vertebral Artery vide Artery Veins of the Dura Mater enter the Brain with the Arteries contrary to those of the Brain it self p. 26 27 28. Two Veins entering the Circular Sinus p. 45 46 How the Veins enter the Sinus's p. 52 53 The effects of their different entrance p. 54 The Veins have a different disposition in the Sinus's of Brutes from what they have in Men p. 54 Veins of the Corpora Striata p. 61 The large reductory Veins of the Plexus Choroeides ibid Vapours condensed into Lympha p. 81 Vascular constitution of Parts p. 91 Veins how continuous to Arteries ibid. Vessels containing the Animal Fluid are capillary productions of Arteries p. 93 Veins only productions of Arteries p. 94 Vessels their minuteness p. 95 96 Vessels of Vessels ibid. Ventricles of the Brain p. 117 Valvula major p. 128 119 its situation and use p. 128 129 130 132 The three Ventricles of the Brain p. 117 Vulva Cerebri p. 124 FINIS ERRATA PAGE 9. l. 14. for to read towards p. 16 l. ult for from which r. which from p. 32. in the title of the Chapter for Veins r. Vessels p. 32. l. 13. after Veins insert which last have already been treated of p. 64. l. 5. dele only p. 89. l. 16. Vitrious r. Vitrous p. 92 l. 29. for Septometry r. Leptometry p. 102. l. 3. for contracted r. contracts Ibid. l. 29. for reflexed r. relaxed p. 109. l. 18. for hastening r. happening p. 117. l. 28. for Semicirculari r. Semicirculare p. 119. l. 12. for becomes r. become p. 138. from And therefore in the 7th line to the end of that Paragraph leave it out p. 137. l. 7. for above r. below p. 168. l. 8. after passage add at least but very little M. Vander Gucht Sculp
of this part may be owing in some if not the greatest part to such a narrowness of the Vessels discover'd here containing the pellucid Substance aforemention'd as will not entertain any Fluid whatsoever without its being first reduc'd into very minute Particles or Septometry so called Which last Vessels I therefore suppose to be only yet more Capillary Productions of the aforesaid Cortical Vessels as they are of the red or Blood-vessels indu'd with such a Pore as fits them only for the reception of a most subtile fine soft Liquor which I esteem the true Medullary and Nervous Juice which being contained in its proper Capsula and many of them collected into one Fasciculus at its egress out of the Brain being there wrapped up in more thick and strong Coverings made of the two outward Membranes of the Brain do constitute that part we call a Nerve which having all its Integuments or Membranous Inclosures always kept turvid and tense by its contain'd Fluid after a slow and leisurely manner continually dispensed from the Fountain and by its growing more taper towards the place of its termination by which means it acquires a greater streightness or narrowness of its Pores ordinarily call'd Fibrillae it so falls out that all inward Impressions upon all occasions are the more easily and speedily transmitted through it The very same notion also concerning Nutrition which in the truest sence is only an apposition of Parts nourishing to Parts pre-existent to be nourished in the rest of the Parts of the Body I have thought reasonable to entertain ever since by assistance of the Microscope I have plainly discern'd the Veins to be only continuations of Arteries and the Blood to run in the same Channel variously modified without the least suspicion of Extravasation viz. a continual transmission of Nutritive Juice out of the Pores of Arteries after many windings like Tindrils of Vines Analogus to which the red Reticular Bodies of Lewenhoeck seem to be in the Brain grown very capillary into certain Tubuli's or Pores of a corresponding bigness and figure making up the whole fleshy part of the Body whose Substance when 't is freed by washing or injection of Water we see to consist only of large and small Blood-vessels and Fibres which last whether Nervous or Membranous or such as relate to Muscular Motion commonly called Carnous I suppose to be full of minute distinct Vessels for the communicating and receiving their proper Liquors or Fluids after the manner already express'd which as contain'd in the said Tubuli or Pores whilst they retain their Natural Constitution and Proportion I presume it is which keeps the Habit of the Body plump and vigorous the more thin and languid being perpetually carried back by the Lymphatick Vessels and a great part wholly exterminated by meer simple Transpiration which I adventure to think is not only superficial from the Sudorifick Glands in the Skin but also through the whole Substance of inward parts through small Canaliculi's or Meantus's in even the Viscera themselves by which not unlikely we may guess at the Meaning of Hippocrates when he said All things were conspirable and transpirable The minuteness of Vessels is that which hath so embroil'd the Thoughts of Naturalists upon this Subject and set Realities so remote from the Understanding otherwise 't is no Paradox to affirm the Existence of Vasa Vasorum almost to Infinitum some containing Liquids in a continual more nimble circulation others in a gentle protrusion only Which will appear altogether unsurprizing if it be consider'd that the aforemention'd Ingenious Author hath computed that even the 64th part of a Miriad i. e. of a Ten hundred thousandth part of any Substance but as big as a small grain of Sand Leweth p. 46. cannot especially if of a rigid or inflexible nature enter those little Vessels which are seen in a retiform manner distributed amongst and fixed to the aforesaid pellucid Globules which swimming in those little Vessels are discover'd to make up both the Cortical and Medullary part of the Brain As also further that even the tender Coats of the smallest of those Vessels which contain the aforesaid most minute Globular Fluid Bodies Leweâ—â—â—â— are also full of yet far more minute Vessels than they themselves are Nay I am so far from being surpriz'd at this kind of Vascular Constitution of Parts that I apprehend not how Nature could otherwise have acted without the consequence of a boundless Accretion inasmuch as that when any parts of a Fluid become extravasate they necessarily lose much of their progressive motion and if of a gross consistence are either proscrib'd by the wider passages or of a finer through those more straight and elaborate viz. by Transpiration so that what Particles of Matter soever continually arrive for either the augmentation or reparation of the Parts must unless the ruine of the Subject do not first happen as we see it often does in Diseases proceeding from such Causes needs if not confin'd in Vessels advance into a monstrous preternatural accumulation as being by reason of their gross consistence altogether uncapable of being carried off proportionably to the measure of their aggestion in the form of subtile Steams or Exhalations Besides a rational explication of the natural Functions which this Hypothesis furnisheth us with it also seems to clear a great many Difficulties which have hitherto puzzel'd the most refined Physiologists relating to the Animal Faculty such as are Sensation and Muscular Motion of which last here in the next place the other being reserv'd for the last Chapter which treats of Sensation and Motion in general CHAP. XII Of Muscular Motion TO recite the Opinion of others upon this Subject would be a thing altogether useless here seeing an Abstract of them is already extant in the Philosophia vetus nova by Mr. Colbert and besides the most correct of them are not only very unprobable but absolutely repugnant to plain Reason and Matter of Fact too an Instance whereof you may have in Dr. Willis's Tendinous Reservatories of Animal Spirits Willis de Mot. Musc p. 35. Mayow de mot musc p. 73. in Dr. Mayow's Twisting or Fiddle-string Fibres with whom of late Mr. Regis agrees by which the Muscle must needs lose a great deal of its thickness than which nothing is more contrary to Experiment in Duncan's first and second Element of Des Chartes Dunc p. 90 which he makes the Animal Spirits to consist of contrary even to the very Principles of that great Man's Philosophy which allows no Elasticity to those Bodies themselves though the Authors of it in all others likewise in Dr. Croon's making the Blood it self Croont p. 23 24 25 33. Philos câ—â— p. 23. as well as the Animal Spirits to be mov'd by the power of the Soul to any Muscles as likewise the extravasation of those two Liquors first into the spaces betwixt the Fibres and then their introvasation into the Fibres themselves again in order
may and doubtless does grow thicker by the shortning of its Fibres yet by that means only it does not become stiffer and harder so as we find Muscles do when contracted by any natural Cause nor is there any necessity it should do so according to any Rules of Mechanism seeing the Fibres shortning only by their own elastick force when they find the circumambient space give way have no necessity of subintration of parts which is always requisite to procure a stiffness or hardness to a part altering its dimensions as Muscles do from a longer and thinner to a shorter and thicker circumference and upon this it must needs follow that in a Muscle contracted by involuntary force in which Action the Brain is altogether unconcern'd that stiffness or hardness then perceivable in it must needs be owing to the Fluid or Spirits in the antagonist Muscle after the manner already explained transmitted to it Now to define what sort of thing this Animal Fluid so called is I see no occasion to frame any other Idea of it than what we ordinarily have of the purest Liquors seeing the Nerves are a Substance which to the Senses of either Smell or Taste discovers very little else than what is insipid are always reckon'd amongst the least hot parts of the Body and doubtless far less warm in Fishes than us who yet have as great a stock of Animal Spirits as any other Creatures And this Consideration may be it was that occasion'd an Author to give the Animal Spirits the Epithite of Frigidiusculi Du His. T. l. p. â—â—â— 'T is plain enough that the Vessels which contains this Fluid are extream minute and consequently the Content must needs be of a very fine and depurate consistence though without much resemblance to either the aforesaid nimble saline or sulphurous Productions of the Fire 'T is in a continual gentle direct motion though perhaps contained in curved or reticulated Vessels from its original source to the ends of the carnous Fibres from whence it is convey'd into the Membranous or Tendinous Productions according as the Fibres terminate and it may be by filtration only in which as in other and particularly in Glandulous Parts not subservient to Muscular Motion where Nervous Ramifications are very copious whether it be of any other use than to keep the Parts in their proper tone in order to their regular discharge of the office of Secretion must still remain a Controversie notwithstanding all that hath been yet advanced against it inasmuch as wastings and numbnesses of Parts the common Symptoms of obstructed or divided Nerves which doubtless by their hastening through such Causes to Muscular Parts gave the first rise to that Conjecture about the Existence and Use of that Juice throughout the whole Body are equally explicable by the want of Tone as of that supposed Liquor To the proof of all this an Experiment frequently made does not a little contribute and that is the injecting the Arteries of a Dog or any such Creature when dead upon which there immediately happens a contraction of the Muscles according to the different strength of them viz. of the Extenders in the hinder Legs and of the Benders in the fore Legs though the Injection be only of cold Water the reason of which effect in particular if it be remembred what hath been before observed viz. that the Blood-vessels do most certainly enter the composition of the Nerves themselves will not only become very easily explicable but the whole Hypothesis at least very highly probable If it be said That this speedy instantaneous reflux of the Animal Fluid is opposed by the aforementioned constant direct motion it hath from its Source to the parts to be moved 't is easie to reply That its slow direct motion that way is casily overcome and repelled by the violent impulse of the forcibly-relaxed Muscle the other way If further it be demanded by what means it so happens that in the Instance before us of an Arm bent by force that the refluent Animal Fluid is rather towards the Muscle which by that means then proves contracted than towards any other whatsoever to all which it may indifferently have access I think the Solution seems not difficult if it be consider'd that at the same time that the one Muscle is forced from the other is forced into a contraction from whence it so falls out that the carnous tubulous Fibres of the last which by being extended under the state of relaxation did lose their cavity must needs by their natural elasticity when freed from the preponderant force of its Antagonist acquire it again by which means a space being made the repelled Fluid by the Laws of Libration to say nothing of the habitual motion of the Animal Spirits or Liquor by most Authors especially Borellus urged as a Reason for this effect must needs be driven thither In fine though I am not averse to think most of the Phoenomena relating to Sensation and Motion may be solved by this Theory tho' of so small an apparatus yet I am so far from being fond of it that I have reserved a far greater share of Friendship for any other that may seem but of never so little more a kin to Truth and submitting all I have said on this Subject to the candid Sentiments of the more judicious Proceedee in describing the other parts of the Brain as they offer themselves in the usual modern way of Dissection CHAP. XIII Of the Brain in particular THIS Part being already describ'd and consider'd in general as consisting of two different Substances commonly called its Similar Parts and the Source of all Sense and Motion comes now to be taken notice of in a more particular manner with respect to its dissimilar parts or conformation and this I think may best be done first according to its outward and next to its inward appearance Outwardly 't is convex and cortical exactly divided into two Hemispheres by the first Process of the Dura Mater called Falx from the bony Process called Crista Galli forwardly to the very hindermost part of the Cranium where these two Divisions are stretched over the Cerebellum from which part also 't is perfectly separated by the second Process of the Dura Mater to the end it may not cause any prejudicial compression upon that part either by its weight or pulsation The foremost Division is made only as deep as the Corpus Callosum the latter to the very Medulla Oblongata it self 'T is further imperfectly divided into four Lobes two whereof which being the less are forwardly and two which are much bigger backwardly These Divisions appear best in the inverted or Varolian Dissection being marked out as it were by four Branches of the Carotid Artery two before and one on each side These I call Imperfect Divisions of the Brain because though the Pia Mater runs betwixt them together with the aforesaid Branches of the great Artery yet they adhere by several Fibres
Annularis and the Thalami Nervorum optici partly cineritious and partly medullary and in fresh Brains somewhat but very faintly striated I know not of any part within the Brain properly so called that is not already described except a certain Medullary Chord at the end of the third Ventricle and the Valvula â—â—ajor Commislura Crassioris Nervi Ae nula of Vieussenius The first of these is a Medullary Process Willis p. 43 col 2. Vituss p. 83. which joyns the Corpora Striata together according to Dr. Willis by Vieussenius called Comissura Crassioris Nervi aemula and according to him is the Medium or Commissura by which his Geminum centrum semicirculare intervening between the two Corpora striata superiora anteriora posteriora and his Tractus medullaris transversus obliquus intervening between his two Corpora striata inferiora anteriora and posteriora have a communication with each other Dr. Willis places this Chord or Commissure under the Roots of the Fornix but it is always behind it Willis p. 6. col 1. tho' contiguous to it The second is the Valvula major The Valâ—â—la major so called by Vieussenius Vieus p. 76. Willis p. 49 col 2. pat 2 but plainly enough discovered by Dr. Willis long before and its proper use described It is a thick especially in Men medullary Membrane adhering forwardly to the inferiour part of the Testiforme Process a little behind that transverse medullary Process from whence the pathetick or fourth Pair of Nerves arise laterally to the Process ascending from the Nates to the Cerebellum on its hindermost Expansion to the foremost Vermicular Process of the Cerebellum and no where that I know of to any part of the Pous Varolii as Vieussenius will have it Vieussen p. 76. Id. p. 73. par 3. who seems to have mistaken another part for that Process unless just where the second Process of the Cerebellum comes out from thence which jointly with its fellow Process on the other side when they meet together after their transverse descent on the back-part of the Medulla oblongata do really make up that part which by Willis is call'd and that no doubt from Varolius Protuberantia Annularis and by others from its true Author Pons Varolii By raising up the foremost above-mention'd Vermicular Process of the Cerebellum with the Finger it rarely fails to come in sight but if not so 't is easily shown by blowing into the Foramen situated under the Pineal Gland It s use according to Vieussenius Vieus p. 110. par 2. is to hinder any part of that Water which falls into the hindermost Foramen behind the Testes from running into the fourth Ventricle or Vice versa from the fourth Ventricle into it or from getting out on each side of the Medulla oblongata over the afore-mention'd Processes so as to fall down upon the Nerves arising thereabouts below from the Medulla oblongata Which last use is evidently most true whether it be understood of Water preternaturally or accidentally collected there for I must needs confess I could never find any there any more than I could in the third Ventricle in Subjects free from those Diseases incident to that part as hath before already been remarked p. 82 but as to that relating to the passage from the Cerebellum to the last or third Foramen I much doubt the Truth of it for many Reasons of which this is one viz. That the Plexus Choroeides in the fourth Ventricle together with the adjacent Parts being of the same Texture as the other are in and about the two lateral ones of the Brain renders it as reasonable to suppose that Water may be collected there as in other parts of the Brain nay that it is so he himself also allows as Matter of Fact and consequently as necessary to have a place of vent for the Water whenever it happens to gather there as it was for that which was at any time got into the other Ventricles And consequently In the next place I do not see how this tender Film can be able to intercept a passage of so searching a body as Water at any time forced against it notwithstanding the supposed declivity of this Part which in Man by reason of the largeness of the subjacent prominent annular Process is very inconsiderable which by Pulsation must needs happen whenever we suppose that Cavity filled with it And in the last place notwithstanding all the Contrivance the aforesaid Author hath shewn in conveying the gross part of the Water which as was before noted he grants may be nay constantly is deposed there from the Glands of the Plexus Choroeides here situate by the Extremities of Veins out of this Ventricle Vieus p. 111 I am suspicious if there was no spedier reductory passage found out there would frequently happen very great Mischiefs to the Medulla Spinalis it self and the Nerves springing from it seeing the Extremity of that Ventricle called the Calamus Scriptorius is there parted from the Spinal Marrow behind it but only by the Pia Mater which notwithstanding it is there double as it is also quite down the whole Spine lest perhaps the Water should fall down upon the Nerves which arise from it too readily yet upon such an occasion may be easily suppos'd subject to violation Not to say any thing of the high improbability of any such Conveyance at all by the Veins seeing that in a natural state they are always as hath been already observ'd continuations only of Arteries 'T is true this may binder the fall of Water into the fourth Ventricle by reason of a Passage under the Nates before mention'd by Vienssenius call'd Aquae Emissarium so near at hand to receive it when it finds its further passage that way obstructed by the interposition and resistance of this Valve And for the same reason doubtless it was that in Vieussenius's Experiment which he brings for a Proof of his Opinion no Water was found in the sourth Ventricle Vieus p 110 par 2. it having got a passage immediately upon its non-admittance by that Valve to convey it another way which by reason of the steepness thereof is done much more readâ—ly CHAP. XIV Of the Cerebellum THE Cerebellum falls next in order to our consideration in describing of which I hope a great deal of pains may reasonably be spared seeing all that hath been already spoken of the cortical or cineritious part of the Brain as also of its medullary part is equally applicable to the Cerebellum Nor is what hath been said already of the Plexus Choroeides in the Ventricles of the one part less applicable to that Plexus in this The Plexus Choroeides of the Cerebellum This Plexus Choroeides in the fourth Ventricle begins to be glandulous just under the Eighth Pair of Nerves from whence it runs up on the side of the Caudex Medullaris to the chordal or third
is that of Instinct relating to the Sensative Soul or an aptitude of the Nervous Structure to act according to the Impressions made upon the Nerves either from within or from without and so may be said to depend on the presence of such Causes as are supervenient and extraneous to Nature suitable to the impressions whereof the Animal either pursues or avoids the Object obeys or resists the Impulse Now I take it for granted that no body will deny but that the Nerves by vertue whereof these last actions of Instinct are performed whether thâ—y â—râ—se from the Cerebrum of Cerebellum are equally under the command of the Soul or else as I said before the Brain in those Creatures is to no purpose And of this sort I reckon all those actions in rational creatures of Instinct before they have attain'd to the use of their Vnderstanding from any sort of Impressions or inadvertent and inconsulted when he hath the controuling power of Reason allow'd him and makes no use of it such as are called Habitual which at first were produced by command of the Rational Part only but through frequent repetitions at last without any command from that out of a blind obedience to a bare impulse from the Object or lastly such as happen when he hath altogether lost the use of it as in Sleep or Distraction in which last Cases 't will be very difficult to distinguish him from a meer Machine or Automaton Now from what hath been said I cannot but think it plain that many of the Actions before spoken of in Dr. Willis's sence by him called Involuntary as proceeding from the dominion of the Cerebellum only such as he calls the various Configuration of the Face from some Impulse or Provocations in the Viscera or elsewhere erecting the Ears turning the Neck and Eyes about sudden Shrieks and Outcries upon some extraordinary frightful Object surprizingly affecting one Sense or another furnished with either such Nerves as he supposes to be altogether under the command of the Cerebellum as the fifth and seventh or else to have a very near correspondence with that part by vertue of Vicinity as the ninth do more truly proceed from that perceptive faculty or to use his own words that part of the Soul he hath confin'd to that part of the Medullary System called the Cerebrum inasmuch as in reasonable Creatures they may and commonly are suspended as well as the Nerves they slow from sometimes made use of as Instruments of Voluntary Motion by it also and to think the contrary is as much as to say that when any body happens to express any of the aforemention'd involuntary Acts or but hit his Bedfellow a box of the Ear whilst asleep all these must be allow'd to proceed only from the Organ of Involuntary Motions called the Cerebellum And of this kind also in a great measure I reckon Respiration concerning which I cannot easily be brought to think it satisfactorily explain'd by Dr. Willis from the Energy of those Animal Spirits which flow only from the Cerebellum in the Par Vagum after the same manner they do to the Heart by the Intercostal and that Pair for its pulsation and as only under the command of the Soul to be stopt now and then as it pleases by vertue of some Nerves communicated to the Intercostal Muscles and Diaphragm the chief Instruments of breathing from the Spina Dorsi I am therefore rather enclin'd to think this Motion is of the other different kind before spoken of under the Title of Instinct proceeding from an extraneous supervenient Cause acting conformably to the course of Nature in oother Cases of the same kind as in Hunger and Thirst and the like where the obtaining the designed End or Effect renders the part from whence comes the Motion for some time insensible of the impression and where after the ceasing of the Effect or Motion the sense of the impression revives again whence there happens an equal reciprocation between the Sense and Fruition or Sense and Motion To apply this account of the manner and reason of the Spirits acting upon the Stomach and Parâ—â—te in relation to Hunger and Thirst to that of the Systole and Diastole of the Lungs or Respiration 't will be needful to take notice that in an Infant unborn there is no Respiration but yet there is a Cerebellum and that if this sort of Motion called Instinct which I make to differ from purely Natural Motions such as are contemporary with even the first living Rudiments of the Individual was altogether and solely owing to the Cerebellum after the manner of that of the Heart then of necessity the Child in the Womb ought to respire But being satisfied of the contrary it remains that we account for its respiration another way which is as afore noted through the presence or absence of the first moving Cause or Impulse which I make or suppose to be any thing impressing the Nerves propagated through the Organs of Breathing so as to transmit the impression from within to the perceptive Faculty presiding both over the Cerebrum and Cerebellum too to the end the Spirits may from thence forthwith be commanded into such other Nerves as act those Muscles which serve for enlarging the whole Cavity of the Thorax in order to let the Air into the Lungs more plentifully which was the thing aimed at by Nature and these are the Intercostal Muscles and Diaphragm Now 't is easie to conceive that whilst the Child is enclosed in its Mothers Belly there is not that occasion for Respiration as when 't is born the main Stream of Blood all that while finding no passage thro' them and that which does by the Ruyshian Artery made of Juices much more mild and cooler the native heat being little and the Aliment meer Chyle or Milk from whence it falls out that the Pulmoniâ—k Nerves go altogether unprovoked which after birth are continually otherwise impressed or provoked by the hot Effluviums of Blood new bred of stronger Food and by a stronger native heat and wholly flowing through them which heat continually as the Child acquires a greater maturity encreasing may for ought I know not a little contribute by way of natural impulse to its exclusion The truth of this will the more clearly appear to any who will take the pains to consider well of the structure of Parts in Children unborn in whom the usual circuit of Blood through the Lungs which are designed for rarifying and perfecting the mixture of Blood and Chyle is denyed as also through the Liver serving chiefly for separating that gross Excrement the Gall not bred at least in any proportion in an Infant unborn and in lieu of these other Passages which become altogether unnecessary after birth provided by Nature after a shorter and more compendious way viz by the Foramen Ovale betwixt the Vena Cava and Vena Pulmon and Tubulus Arteriosus between the Art Pulm. and Aorta in the Lungs and