solid meats and together with the drink serve as a fit Menstruum to extract the laudable and alimentary parts of them ad modum tincturae But this liquation of solid meats in the Stomach seems to be effected by motions placid gentle and imperceptible in the state of health not by those violent commotions and irrequiet agitations that always proceed from and accompany Ferments properly so call'd during their working as all men that enjoy good health feed soberly and keep a regular course of diet may easily observe in themselves And therefore this Acid Phlegm cannot properly and in Philosophical strictness be referr'd to the family of Ferments The same may with equal reason be said also of the Bile and Pancreatic juice commixt in the Duodenum They may perhaps conduce somewhat to the farther attenuation and exaltation of the Chyle they may also promote both the separation of the Nutritive from the Excrementitious parts of the same Chyle and the insinuation and permeation of the former through the coats or membranes of the Guts into the milky veins all this they may do and yet not by way of Fermentation whereof there is neither necessity nor sense in statu sanitatis and to argue from a preternatural state to a natural is a Paralogism Now if neither of these two so much celebrated Ferments hath any more right to that denomination than what is precariously derived from some remote and slender analogy or semblance imagined to be betwixt their nature qualities and effects and those observed in genuine and true Ferments as certainly neither of them yet appears to have What ought we to think of all the rest of invisible Ferments supposed to reside in places where hitherto they have never been found Why may we not till they shall be by Anatomical and other convincing experiments shewn to us believe that they have existence no where but in the brains of fancyful men For my part I blush not even in this venerable Assembly of most Learned men where I have as many Judges as Auditors openly to profess my self to be of this belief because de non apparentibus de non existentibus eadem ratio est and because I have heard an eminent Member of this first and more ancient Royal Society a man renowned over all Europe for his Philosophical and Anatomical Writings deliver this judgment of the multiplicity of Natural Ferments fancyed to be in the body of an Animal that they were a new-found asylum ignorantiae I say of Natural Ferments lest what I have said should be detorted to the exclusion of Praeternatural Fermentations which I do not deny to be incident sometimes to the bloud and other humours of the body more signally in Fevers and some other acute diseases though perhaps not so often as vulgar Physicians imagine What I have hitherto said may perchance seem to some of my Auditors to be a digression and they may be apt to think that I have made my first step in a wrong path I am therefore obliged in my own defence to advertise them that having proposed to my self to enquire strictly into the natural necessity or Mechanical reasons of the Motions of the Bloud and finding the aforesaid Comment of Ferments lying like a block in my way I thought it concern'd me rather to remove than to leap over it and leave it for others to stumble at For some there are and those too men whose names are deservedly celebrated for their profound knowledge both in Anatomy and the Mathematicks who in their books have professedly taught that even the bloud it self the seat of life also undergoes a certain natural Fermentation in the heart lungs and greater arteries as necessary to its perfection and vitality A doctrine which to me I profess seems very improbable and inconsistent with the wisdom of Nature Improbable First Because of all the various liquors found in the body of an Animal in statu Naturae the bloud seems of it self least prone to Fermentation which is incident chiefly if not solely to new and musty liquors whereas the greatest part by much of the bloud is old and by repeated Circulations well defaecated in its proper Emunctories and by insensible transpiration and by consequence needs no Fermentation True it is indeed that new Chyle is ever now and then brought into the rivulet of the bloud out of the common cistern thereof by the ductus thoracicus and the Subclavian vein for a recruit but in a quantity so small a few drops perhaps at once for more will not be found to bear a just proportion either to the capacity of the common Receptacle of the Chyle which is but little or to the narrowness of the Pipe leading from thence to the Subclavian vein as cannot in reason be thought sufficient to perturb and excite a fermentation in the bloud with which it is mixt If a greater quantity of Chyle were mixt with the bloud at one time certainly the bloud would soon lose its native purple and put on the white livery of the Chyle especially in the descending part of the Vena cava where the commixture is first made which yet no Anatomist for ought I know hath ever observ'd Secondly When Ferments are commixt with liquors consisting of heterogeneous particles they are generally slow in exerting their power and by degrees insinuate and diffuse their active particles through the whole mass before they can so far prevail as to raise an universal commotion and tumult in them as common experience testifies but the newly commixt Chyle and bloud are in a moment at most in the space of a few pulses of the heart rapt out of the Vena cava first into the right Ear and then into the right Ventricle of the heart so that here is no morula no competent space of time given to excite an actual fermentation Thirdly Here is wanting also convenient place To all Fermentations is required fit room wherein the liquors may have liberty to undergo an impetuose commotion and agitation of all their dissimilar and contrasting particles nor will the Must of Wine it self ever ferment if it be kept in close and strong casks as appears from the making of Stum but the Vena cava the Heart and Arteries are fill'd with bloud even to distention till by their Systole they squirt it forth and then in the next moment they are replenished What room then is left for the bloud to ferment in Seeing therefore that the bloud is by its own constitution unapt to ferment as bearing a greater analogy to the nature of Milk than to that of Wine whatever the Willisians have said to the contrary and seeing that neither the small supplies of Chyle which it daily receives are sufficient to induce nor the shortness of the time in which it passes through the praecordia nor the want of convenient room permit a fermentation what reason have we to assent to their opinion who teach that a fermentation of the bloud
marrow which are sent down directly into the substance of the heart as if the more easily to convey some influence into it No great difference this and yet the cause that induced Nature to make it may be great What it is is difficult to find out It may probably have some respect to the prone posture of Brutes which being horizontal must cause the ponderose machine of the heart to swagg and the cone to point not toward the midrif as in erect man but toward the Sternum and therefore in them there might be need of more auxiliary Nerves to assist the hearts motion in that position But whatever may be the true reason I do not assent to their conjecture who say that because the heads of beasts look downward therefore the providence of Nature hath furnished their hearts with more Nerves lest Animal Spirits should not in sufficient swarms be sent every moment from the prone head into the heart of a Brute that position of the brain forsooth rendring the transmission of these Spirits more difficult and slow And the reason why I do not assent to this witty conjecture is because neither the Authors of it nor any other man whose writings I have read have sufficiently proved that there are such things as Animal Spirits in rerum naturâ In some books indeed whole Common-wealths of them are found so that ye can hardly pass along without meeting crouds of them But till I see their Existence otherwise than precariously asserted I am justly excusable if I doubt thereof The Heart being thus composed of many myriads of strong Fibres of various orders by most dense contexture compact and of various Nerves intersperst it required to be continually cherished with due heat as well without as within Wherefore the Heart having no heat but what it receives from the bloud in which only the true Calidum innatum the lar familiaris resides Nature hath furnished it with two Arteries for its own peculiar use divided almost from their origine into two trunks the Orifices of which open themselves near to the beginning of the aorta immediately without the Valvulae Semilunares They are fitly called Coronary Arteries because their trunks do not presently enter into the parenchyma or substance of the heart but first make their tour or circuit the more commodiously to disperse their branches round the basis of it in manner of a crown or rather a Diadem and though from their very original they divide and recede the one from the other to the opposite regions of the heart yet they meet again in their extream branches and by mutual Anastomóses or inosculations communicate betwixt themselves so that if any liquor be injected into either of them it will in a moment appear to diffuse it self also through the other And this mutual Communication seems to be design'd to a good end For since the necessity of influent heat or life is equal in all parts of the heart that necessity could not be more commodiously satisfied any way than by this Artifice of mutual inosculation betwixt the extremities of these two Arteries No sooner hath the bloud thus imported communicated its vital heat to the substance of the heart than it is thence exported by the two Coronary Veins which in like manner encompassing the heart and by their numerose emissary surcles imbibing the bloud effused out of the Arteries reduce it into the right Ventricle thence to be brought through the Lungs back again into the left So that here is a private circulation in a small circuit instituted for the peculiar benefit of the Heart As the extreme surcles of the Coronary Arteries are mutually inosculated so also are those of the Coronary Veins as is apparent from ocular inspection For if you take the heart of a Calf or any other very young Animal for in such these vessels are most easily discernable and with the back of a pen-knife gently impel the bloud from one side of the heart toward the other you shall see it flow out of the Vein of one side into that of the other and vice versâ Nor is it to be doubted but that in all other parts of the body there is the like mutual communication per anastomôsin betwixt Capillary vessels of the same kind Besides the proper vessels of the heart now described there are annext to its basis also two Subsidiary Muscles hollow and round from thence call'd Auriculae cordis framed with no less art than the Heart it self though of less bulk For they are composed of robust Fibres too and disposed in the same order and as their motion precedes that of the Heart so have they Nerves from surcles of the Eighth pair before they reach to the heart it self Besides their intermediate fleshy Fibres which form little musculose columns are elonged to opposite Tendons For the Tendon at the basis of the Heart is common also to the ears of it and serves them for a fulcrum or prop and on the other part of the right Ear where it respects the Vena Cava it is firmed by a harder and Tendinose circle betwixt which two Tendons the Fibres tending to each are terminated as appears in the right Ear of a human heart inverted Of these Ears the right is always greater than the left Perhaps because the flux of the bloud being less rapid out of the Vena Cava into the right Ventricle of the heart than out of the Arteria Venosa into the left whither it is impell'd by the compression of the Lungs and by the coincident elasticity of the inspired air it was therefore requisite the capacity of the right Ear should be proportionately larger to receive and transfund into the right Ventricle a quantity of bloud sufficient to fill it For evident it is that the office of these Ears is like that of funnels to transmit the bloud into the Ventricles of the heart For the same reason the trunk of the Vena Cava when it approaches to the heart participates somewhat of the nature of a Muscle For there it is furnished with fleshy circular Fibres by which it is constringed and consequently the bloud running through the canale thereof is urged the faster into the right Ear in the same manner as when a gut or bladder is outwardly constringed by the hand the liquor therein contained is expressed and its regress hinder'd We have now survey'd the Structure of this admirable Machine the Heart at least so much thereof as may serve to render more plain and intelligible what I am about to say concerning the Action thereof To which I now pass ¶ ⸫ Evident it is both to the sight and to the touch that in the act of Pulsation the whole fleshy substance of the heart is stretcht and hardned with very great force as all other Muscles are when they act and certainly this tension and induration arises from the very Structure of the heart For the Fibres of the columns of it and their
bloud Which is alone sufficient to evince that the Arteries do not remain empty after the pulsation of the heart but contain at least a 4 th part of the whole mass of bloud which in a man is about 5 pints Yet farther the Arteries in the moment of their pulsation are highly turgid when yet not above 3 ounces of bloud is emitted into them by the Systole of the heart Therefore if before the Systole the Arteries were wholly empty a space 20 times greater than their bulk is would inevitably be filled by the 3 ounces of bloud emitted by the heart but this certainly is impossible without such a rarefaction of the bloud which no man of common sense will admit Therefore to replenish so great a vacuity in the Arteries there must come into them five pints of bloud either from the heart or back out of the Veins but neither of these is possible in nature Let us add that 3 ounces of bloud emitted by the Systole of the heart cannot fill a space greater than half a foot of the next Arteries to the heart Therefore if the Arteries were empty before the Systole truly all the rest of the Arteries would remain empty also in the following Systole and consequently could not beat at the same time with the heart and the Circulation of the bloud through them would be interrupted or discontinued contrary to the mechanic necessity thereof In fine we are convinced by common experience when an Artery whether it be great or small is cut the bloud is in every pulsation squirted out with mighty violence Now it is impossible this should happen unless all the Arteries were full of bloud all along from their beginning to their end because the violence of the stream of bloud gushing from the incision hath no other efficient cause but the protrusion of the bloud coming on behind and urging the antecedent But in the following pulsation there is an accession of no more than 3 ounces of bloud which cannot by its quantity replenish half the capacity of the Arteries Therefore unless there remain after every pulsation 5 pints of bloud in the Arteries they cannot be made turgid again in the following pulsation So that nothing is more certain or more evident than this that in a living Animal the Arteries are never empty Quod erat ostendendum From the praecedent Theorem naturally arises this Consectary That after the pulsation of the heart there remains in the Arteries the 4 th part of the whole mass of bloud conteined in the body of an Animal and in a man commonly about 5 pints and that the proportion of bloud expressed by the Systole of the heart into the Arteries is about one twentieth part of the bloud contain'd in them As also that 3 ounces of bloud ejected out of the heart into the Arteries fill a space in the Arteries next to the heart no greater than half a foot namely so much as is triple or quadruple to the latitude of the Ventricles of the heart PROPOSITION That the motion of the Bloud in the Arteries is threefold swifter than the motion of the Heart that impells the Bloud Because in the same time are absolved all these motions viz. the dilatation of the Pores of the heart the restriction of its Cavities by the swelling inward of the walls of the Ventricles the expulsion of the bloud contein'd in the Ventricles the motion of the expulsed bloud in the Arteries and the promotion of the mass of bloud praeexistent in them caused by the urgency of the new bloud coming on out of the heart all these actions I say are performed in the same time And it appears that the three former operations are performed with the same velocity in the heart because the Fibres of the heart by reason of their abbreviation are with the same motion moved through the same space of the amplitude of the Ventricles through which they are moved by restringing the same Ventricles and squirting out the bloud that was conteined in them And the two last operations likewise are performed with the same velocity For look how much space the bloud expelled out of the heart runs through in the Arteries just so much space must the mass of bloud praeexistent in them be driven through in the same time because one part of the bloud must give way to another urging it forward as fast as that comes on behind But if the motion of the constriction of the heart be compared with the progressive motion of the bloud in the Arteries then doubtless they will not be found to be of equal velocity because the former motion viz. of the constriction of the heart is made through a space equal to the latitude of the Ventricles of the heart which at most excedes not 3 inches breadth but the space through which the 3 ounces of bloud expressed out of the heart run in the Arteries is equal to the length of half a foot Therefore the space will be triple at least to the space of the former motion and yet both these motions are performed in the same time Ergo the motion of the bloud in the Arteries is threefold swifter than the motion of the heart that causes it Quod erat propositum I add this remark that the motion of the bloud in the Arteries is always the same whether the three ounces of bloud emitted into them out of the heart exactly fill the space dilated in them or whether any portion of it be after their repletion expell'd out of them For in both cases the bloud praeexistent in the Arteries is just so much promoved in its course as 3 ounces newly emitted take up of space which run through more of length than half a foot ¶ ⸪ Here I cannot fairly decline to encounter a vulgar error that stands in my way Which is That the bloud is expelled out of the Orifices of the Arteries into the substance of the Parts by no other cause but the constriction of the Heart To refute which I will assert this PROPOSITION That the cause expelling the Bloud out of the Arteries is not the Systole of the Heart alone but the constrictive or peristaltic motion of the Arteries themselves naturally and necessarily succeeding their expansion To the pulsation of the heart two effects are subsequent viz. the repletion of the Arteries by the bloud emitted into them and the expulsion of the same bloud out of them into the habit of the parts Now certainly these two operations cannot be performed together or at the same time because the former is done by dilatation and the other by constriction of the same Arteries which two contrary motions cannot be coincident Wherefore it is of absolute necessity that the repletion of the Arteries be precedent and the evacuation be subsequent But the repletion cannot be made without a violent distention of the transverse or circular Fibres of the Arteries and we all know that all the Fibres of vessels no less than those
cylindrical fasciculi or combinations have not their ends fastned to Bony or Tendinose props as most other Muscles have but relying only upon and having both their beginning and end in the pendulous heart itself are retain'd by an instable foundation or hypomochlium yet with tenacious firmness Hence it comes that the turgency of the Fibres of the heart seems not to have been ordained by Nature for the traction and approximation of their extreme terms but on the contrary that there might be made a decurtation or shortning of the Fibres that by their swelling they might restringe and lessen the hollow perimeter and so like a Press squeez out the bloud therein contein'd just as boys Spirt the stones of plums by compressing them strongly betwixt their thumb and fore-finger This is evinced from hence that in every Pulsation or Tension of the heart the bloud contein'd in the Ventricles is with very great violence Squirted out into the Arteries as water is Squirted to great distance out of a Syringe by the embolus or rammer But more evidently by putting your finger into a hole made by incision in the heart of a living Animal For in every Systole of the heart you shall feel your finger pinched all round about as by a pair of pincers by the swoln and indurated flesh of the Heart Though therefore the external superficies of the heart be not in the Pulsation augmented yet certainly the whole fleshy substance of it is at that time truly swell'd up and increased and indurated Here I have affirmed two things difficult to be conceived more difficult to be proved The one is that the decurtation of the Fibres of the heart which always is effected in its act of Pulsation doth by lessening the cavities of its Ventricles express the bloud contein'd in them The other is that though in the same Pulsation the outward superfice of the heart be not augmented yet the whole fleshy substance of it is so enlarged as to fill a greater space than before Wherefore since this action of the heart cannot be clearly understood unless the Mechanic reasons of both these Propositions be first explained and since that work hath been done to our hands with great labour of mind and profound judgment by that excellent Mathematician Io. Alphonsus Borellus in his second Volumn de motu Animalium not long since published I chuse rather in so obscure a way to lead my Auditors of the Younger sort by his brighter Torch than by the Glow-worm light of my own understanding Omitting then the Lemmata or introductory propositions by him premised to his demonstrations of the Mechanic reason of the Action of the Heart I will venture to make my self an Interpreter of so much of his Theory concerning that abstruse subject as seems to me requisite to the explication thereof referring those who shall not be satisfied with my Epitome to the book it self in which the argument is treated at large and more Mathematico I begin from his 47 th Proposition Let us represent to our imagination a glome or bottom of small twine or thred ABR hollow within composed not of one thred but many and those too tied to a ring or the semidiameter of the glome AETR fixed and to the superfice of the cavity and wound about Concentrically or Spirally Now if the cavity be filled by swelling of the threds by their humectation the internal threds MOQ must be corrugated or shrivelled up unequally always the more increasing their wrinkles or folds by how much the nearer they come to the Center and the external Figure of the glome will remain unaltered Because in a Rope of Hemp whether the Rope be made of a single twine or composed of many twines twisted together Spirally the external Spires do in the same order strictly embrace and bind down the internal Spires so that they cannot be removed out of their places we see that ropes are equally by humectation swelled contracted and suspend equal weights Therefore in like manner glomes of thred composed of one or more threds ABR ought in the same manner to be swelled and their cavities MOQ to be filled by that swelling For the beginnings and ends of their Spires are with equal firmness retein'd in the same places whether they be mutually knit by continuation or whether they be tied or fastned to the rings or other firm places of the glome as in the 4 th Figure For in both cases the threds are the same of the same form disposition and thickness and the external threds by their Tension spirally gird in and embrace the internal therefore they must become in the same manner thicker by a few drops of water and consequently in the same proportion corrugated always so much the more shrinking into little wrinkles by how much the nearer they approach to the Centre and their external Figures will remain of the same bulk and magnitude To accommodate this to our present Theme I say that when the Porosities of the Fibres of the Muscle of the Heart are by internal humectation dilated the cavities of it ought of necessity to be filled by the fleshy substance of it without variation of the external Figure thereof For because the Heart is a glome hollow within composed of innumerable Fibres Spongy very strong and not extendible in length which Fibres are fastned to the Tendinose rings of the four orifices of the heart and spirally involved and contexed and because all these Fibres are by internal humectation swell'd no otherwise than the twines of a rope and the threds of a glome are made to swell and become turgid by a few drops of water insinuated into their pores Therefore by the same necessity by which a glome contexed of threds is transformed inwardly must the cavities of the heart be filled the internal Fibres of it being corrugated and shortned unequally always augmenting their swol'n wrinkles by how much nearer they approach to the Centre of the heart the external Figure of the heart being the while neither augmented nor diminished And thus is the difficulty of the latter of our two Propositions solved Let us therefore in the next place resume the consideration of the former viz. That the constriction of the Ventricles of the Heart cannot be made by the force of the contraction of its Fibres If according to the common doctrine of Anatomists the proper action of all Muscles be a Contraction of their Fibres then it may seem consentaneous that the proper action of the Muscle of the heart should also be a contraction of its Fibres and because the heart is not tied or bound to any joints as most other Muscles are for the bending of them but ought only to constringe its own Ventricles let us see whether the Ventricles of it may be constringed by a simple contraction of its Fibres or not And First if the Heart be like to a glome composed of threds spirally involute it is manifest from what hath been
of the Ventricles of the heart is the sole and immediate cause of the expression of the bloud that was conteined in them into the Arteries For the swelling or incrassation of these opposite walls being all inward toward the Centre of the heart and withal so great as to fill up the cavities of the Ventricles it is necessary that the bloud contained in the cavities being on all sides vehemently compressed give way and flow forth through the apertures or Orifices by Nature provided for its efflux the resistence of the fluid bloud holding very little proportion to the mighty force of the solid compressing it But so grand an intumescence of the fleshy substance of the heart could not otherwise be made than by a great swelling and turgency of its Fibres and therefore we may infer that the thickness of the Fibres of the heart is in the act of Pulsation doubly greater than in the diastole This being granted I consider that the external Fibres of the heart exercise very great force not by shortning themselves but by resisting distraction as the iron hoops of a hogshead that the perimeter of the heart be not augmented and at the same time they are inflated in their Concave part or under side as we have said the threads of a glome are and in like manner the internal Fibres when they are swell'd and incrassated exercise very great force by making folds and turgid wrinkles so tense and rigid that they do the office of wedges by which not only the cavity of the heart is filled up but the bloud therein conteined is by vehement compression squirted out by a motion very much resembling that by which we spirt Plum-stones with our Thumb and fore-finger compressing them behind But the slender fleshy Columns holding in the opposite walls of the Ventricles of the heart are at the same time also incrassated and withal shortned their Fibres being swell'd and corrugated to help fill up the cavity Yet they exercise greatest force to perform the office of wedges They exercise none towards the drawing together the opposite walls of the Ventricles because themselves are lax by reason of the corrugation and shrinking of the length of their Fibres and besides this they could never exactly conjoyn the opposite walls because being of a musculose constitution they cannot be totally shortned the nature of the Muscles being such as suffers not contraction greater than the third part of their length Yet it cannot be denied but these musculose Columns serve as cords to retain and conserve the due disposition of the internal parts of the heart and to prevent the immoderate distension and distraction of the Ventricles which too great a quantity of bloud rushing into them out of the Veins might otherwise cause Finally the Papillae or little fleshy teats standing up within the Ventricles and to which the membranose filaments of the triangular valves of the heart are fastned do also act their part in this Scene not only by admitting the like inflation of their Fibres but also by firmly erecting themselves ad instar penis All these things are verified in the left Ventricle and in the Ears of the heart but in the right Ventricle where is not found an equal number of Columns the constriction is made by incrassation of the external wall namely by inflation and decurtation of the Fibres thereof so that the hollow crookedness of it by swelling inward comes near to a Plane and the Arch within becomes streight Also the inflation and swelling of the Septum cordis or middle wall of the heart of great thickness naturally contributes not a little to the repletion of the right Ventricle For hence it is that the Convex superfice thereof doth become more prominent and stretched out whence that space resembling the figure of a concave Lens is filled up and the walls mutually touch the circuit of the Lenticular cavity remaining still the same Now this whole operation is exactly conform to the institute of Nature which primarily fills and amplifies the Pores of the Spongy Fibres by the humectation above explained from which she attains to a double effect For in the Muscles of the Limbs that swelling of the Pores of the Fibres produces a secundary effect which is the decurtation of the Muscle and the strong traction of the joynt but in the heart from the very inflation of the Fibres and consequent incrassation of the walls she effects the repletion of the Ventricles But the Machine is the same in both namely the force of a wedge dilating the Pores of the Fibres But that this expression of the Bloud out of the heart is not made by a Spiral contorsion or twisting of the heart such as that by which water is commonly squeez'd out of a wet napkin as some late Writers have thought is easily to be proved I acknowledge it to be most true that the expression of the bloud out of the heart no less than the wringing of water out of a wet cloth is made by constriction of the Cavities and Pores which were filled by the fluid but at the same time I deny that such a constriction is made in the heart and such an expression of the bloud thence by the same cause the same Organs and the same Mechanic action by which water is squeez'd out of wreath'd Linnen For in a Linnen cloth before its Contorsion the threds were all lax and therefore they admitted many Interstices that might be filled with little drops of water Afterward the cloth being strongly twisted the threds are forced to make many circuits about the twist of almost the same altitude and so they must not only be much elonged in those prolix Gyres but also extenuated and stretch'd and consequently their sides being made smooth by extension of their folds and wrinkles will mutually touch and their interstices vanish whence the little drops of water that were in them before will presently be squeez'd out But in the heart the repletion of the Ventricles is performed in a manner far different from this For in the act of Pulsation the bulk of the heart is not extenuated or diminished but rather augmented in a double proportion nor are the Fibres of the heart elonged but rather contracted as the nature of all Muscles requires The same Fibres do not mutually touch nor are their interstices fill'd up by reason of violent traction and extension but of their inflation Notwithstanding this we are not to think that the Spiral disposition of the Fibres of the heart is of no use For they serve to the firm binding or hooping as it were of the walls thereof that the face and configuration of the heart may continue still the same which Nature hath provided for also by Girths of other Fibres wound round about from the external Tendinose Orifices of the Vessels of the heart to the Columns within and with admirable Artifice decussated and woven together And thus we have made good our
Proposition That the proper Action of the heart is the Constriction of its Ventricles and the consequent compression and expression of the bloud contein'd in them not by a Contorsion of its Spiral Fibres but by an inflation and corrugation of them Here some perhaps may be willing to propose to me this question If it be true that in the Systole or act of Pulsation neither the exterior Superfice of the heart is augmented nor the Cone of it drawn up toward the Basis both which we have asserted how then comes it that in every Systole the Cone of the heart knocks against the left side of the breast Which may be thus Answer'd Because the heart is hung in the middle of the Breast by strong Ligaments and yet in every Systole is brought to touch and strike the inside of the Breast therefore it is necessary that this be done either by a dilatation of the heart or by local motion and translation of it or by erection of the whole or by flexion and incurvation of the Cone thereof And as our observation and experience rejects the three former causes of this Phaenomenon so it obliges us to embrace and acquiesce in the last Wherefore it remains only that we investigate the Mechanic reason of this effect Which seems to depend first upon the disposition of the Fibres of the heart For we see that a crooked gut tied about with a thred and not wholly fill'd with water is by the weight of the water extended directly or in a strait line but if the water be impelled toward either end by compression then the gut becomes crooked again as the nature of it exacts and the other pendulous extremity will be erected and strike against your hand held a little over it This plainly follows from the curve figure of the membrane of the gut which is longer in the convex part and shorter in the concave So in the left part of the Ventricle of the heart the left wall is shorter less fleshy and less crooked than the two walls that make the right Ventricle Wherefore in the Systole of the heart the Cone of it ought to be erected toward the left side of the breast and to strike against it more or less strongly according to the degree of violence with which it is erected This may be somewhat helped also partly by the erection of the heart lying obliquely partly by the situation and disposition of the Fibres which are wound about obliquely and spirally from the right side of the Basis of the heart toward the left side of the Cone whence in the act of Pulsation when the Fibres are shortned the Cone may be a little distorted and erected by the fasciculus or combination of Fibres forwards toward the left side and so the Percussion may be made Seneca as ye may remember in epist. 57. most elegantly describes first the inevitable horror that invaded him while he was passing through the dust and darkness a darkness so thick as even to be seen of the Crypta Neapolitana now named the Grot of Pausilype in the way between Naples and Putzole and then the chearfulness he calls it alacritatem incogitatam injussam that returned to his mind upon the first sight of the restored light The same surprising alacrity methink I now feel within my self after my passage through the no less darkness in which Nature had through a long Series of ages involved her great secret of the Motion of the Heart made more obscure by the dust of mens various opinions and my arriving at the light of knowledge both what is the proper Action of the Heart and by what Mechanic necessity that Action is performed In the ardor of this alacrity I proceed to the use and action of the Ears of the Heart and of its Valves The end of the Vena Cava which is conjoyned to the heart is as hath been said before in greater Animals Musculose round about that the trunk of it may be constringed as Sphincters are closed by virtue of their circular Fibres But the end of the Vena Pulmonaris wants the like fulciment and therefore cannot constringe itself Then both these Veins end into the Musculose Ears which are hollow like little bags affixed to the sides of the heart and whose structure much resembles that by which the left Ventricle of the heart is contexed in the hollow part of it For the Ears also consist of fleshy Fibres intersecting each other like a St. Andrews Cross which within are bound together into many little Cylindrical Columns and trenches connecting the sides of the bags To these Ears succede three membranes in the right Ventricle and two in the left which are of a very strong contexture of a triangular figure the bases of which are closely affixed to the whole Circuit of the Tendon of the Orifice of the heart Then the areae or middle spaces of these little membranes are branched within the Ventricles of the heart into many little Tendinose Strings or cords which are fastned to the tops of the papillae or teats that stand pointing upwards placed on the opposite side Now this admirable structure being known let us enquire the design or use of it First the extreme part of the Vena Cava seems not to be made Musculose for strength lest it should be broken by the current of the bloud rushing in but rather by its constriction to protrude the bloud into the oblique Sinus of the right Ear and to render the same turgid Which action is helped by the peristaltic constriction of the whole trunk of the Vena Cava and by the compression of the Muscles and Viscera of the whole body as was yesterday demonstrated when we considered the motion of the Bloud Hence it comes that the bloud impelled through the open aperture of the Ear fills the cavity of it and then runs into the right Ventricle and by the like necessity the bloud flows out of the Vena pulmonaris into the left Ear and thence into the left Ventricle of the Heart No sooner are the Ears filled and distended with bloud but they both at the same time constringe themselves by a contractive and compressive action common to all Muscles resembling that of a Press in this order that first by shutting their apertures they hinder the regress of the bloud into the same Veins out of which it came in then by the great force of compression they squeez it into the Ventricles of the heart until they be filled and made turgid To this action of the Ears immediately succedes the compression of the press of the Heart itself by which the bloud itself by reason of its abundance inflating and distending the triangular and mitral valves exactly shuts the Orifices or mouths of the Veins and so prevents its own recoiling into them Whence it is of absolute necessity that the same bloud be expressed into the Pulmonary Artery or Vena Arterialis and into the aorta These are the
Actions and Uses of the Ears and Valves of the heart first discover'd by our immortal Dr. Harvey and since confirmed by various experiments of other excellent Anatomists Being then certain of the Phaenomena it remains only that we endeavour to explore the Mechanic causes of them In the first place because the Ears of the heart are Muscles round hollow and composed of fleshy Fibres wound about Spirally and intersecting each the other decussatim and because they end into little columns and trenches in the same manner as the left Ventricle is framed therefore must they operate by the same Mechanic necessity and Artifice by which the heart operates viz. by the force of a Press and by wedges insinuated into the Pores of their Fibres they must be swell'd and so constringed and consequently express the bloud contein'd in them Secondly That the constriction of these Ears ought to precede the contraction of the Ventricles of the heart though both motions seem to be performed at one time may be thus demonstrated For if this be not true then either the Ears and Ventricles of the heart are constringed in one and the same moment of time or the heart is first constringed and then the Ears If the first because the triangular valves have no use before the heart is constringed nor after the constriction of it is complete because the shutting of the Valves would be in vain when the bloud cannot flow back and slow back it cannot before the heart is constringed because then the bloud is not yet in the Ventricles and so cannot be impelled by the Systole of the heart and after the constriction of the heart the expulsate bloud can much less flow back therefore it is necessary that at what time the Ventricles are constringed at the same time the Venose orifices ought to be exactly shut by the Triangular Valves that the bloud may be impelled not backwards but forwards into the Arteries But if at that same time the Ears were constringed they would inevitably vomit out the bloud contein'd in them into the Ventricles and so open the clausure made by the triangular Valves because they are so disposed as to be opened and dilated by the very coming of the bloud Wherefore at the same time the bloud would be impell'd by the Ear into the heart and repell'd by the heart and so these two contrary motions would mutually destroy each the other and both be in vain Besides when two outlets are at the same time open in one Ventricle of the heart the whole compressive force of the heart is divided into two equal parts which impell the two halfs of the bloud one backward the other forward into the Arteries and therefore Nature would foolishly by a double endeavour attain but half her end We may add that the triangular Valves would be wholly useless since they would then urgente necessitate be open when they ought to be shut Wherefore it seems impossible that the Ears of the heart and its Ventricles should be constringed at the same time But if we suppose the natural order to be inverted i. e. that first the Ventricles of the heart are constringed and then the Ears compressed this would be much more absurd for half of the bloud contein'd in the Ventricle would flow back into the Ear on both sides open and thence into the Vein It must therefore be confessed that the constriction of the Ear ought to precede and then immediately ought the constriction of the Ventricle to succede and then all the operations procede regularly and compendiously For the Ear being comprest first the regress of the bloud into the Vein is hindred next the bloud is expressed out of the Ear into the cavity of the heart Thirdly the Orifice of the heart is shut by the constringed Ear Fourthly the Ventricle of the heart being filled with bloud and distended the Membranes of the triangular Valves are expanded These actions being in this order of succession done then in the fifth place follows the swelling of the heart by which all the bloud in the Ventricles which cannot by reason of the double clausure slow back is forced to run forth by the open door of the Artery Thirdly it is observable that the action of the right Ear differs from that of the left because the bloud ought to flow out of the Arteria Venosa or as some call it the Vena Pulmonaria which is very ample into the left Ventricle of the heart with a swift current by reason of its gravity and of the compression of the Lungs For this reason a little Ear is sufficient to transmit the bloud so swiftly running into the left Ventricle and with the help of the mitral Valves also exactly to shut the aperture of the heart On the contrary in the right Ear the slowness of the blouds influx ought to be compensated by the amplitude of the Canale And moreover because the right Ear ought not only to close the Orifice of the heart but also to impel rapidly the slow paced bloud into the right Ventricle therefore Nature hath made the Muscle and cavity of the right Ear stronger and larger than that of the left Fourthly We may farther gratifie our curiosity by considering the manner how the triangular Valves exactly shut the Orifices of the heart which seems to be this Because these Membranose Valves have their bases fastned to one part of the circular Tendon of the Orifice of the heart as flags are fastned to their staves and their other sides are by many Tendinose Filaments or strings fastned to the fleshy teats in the opposite part of the cavity of the Ventricle as Webs of Linnen exposed to the Sun are kept upon the stretch by many small cords tied on each side Hence it comes that by the stream of bloud rushing in the cavities of the Ventricles are dilated and so these Membranose Valves which before were lax and flagged are drawn and expanded transversly so as to spread themselves through the whole space of the Orifice Necessary it is therefore that the points and sides of these Triangular Valves thus drawn by the little cords decussated should be conjoyned and being conjoyned make one Conical superfice greater than the plane of the Orifice or of the circle of the basis of the same Cone After this follows the Systole of the heart when the insides of the Walls of the Ventricles are united and therefore those little cords of the Valves are at the same time relaxed and united also and so the faces of the Triangular Valves themselves must be united and acquire a Sinuose or embowed figure their Superfice not diminish'd because their membranes are not contracted Whence it comes that the bloud filling the Ventricle doth by repelling the membranes and inflating them bow them as the Sails of Ships swell'd by the wind are bowed into a hollowness Again since those membranes thus embowed are transfer'd toward the Tendinose Orifices of the heart the round area of
which they far exceed therefore it is necessary they should exactly shut those Orifices before the Systole of the heart is complete Wherefore it is also necessary that the bloud contein'd in the cavities of the Ventricles should by the process and continuation of the constriction of the heart until a total union of their walls be effected be all expressed thence through the Arteriose Orifices which are then open to give it free egress Fifthly If the clausure of the Ears did not precede those little and thin Valves would not be able to resist that mighty violence with which the bloud comprest by the heart invades them and otherwise would certainly break them therefore to secure them provident Nature hath put a fleshy fornix or Vault viz. the constringed Ear that she might with a double door shut the ample Orifice of the heart Hence naturally arises this remarkable Corollary that the action of the Ear is longer in time than the Systole of the heart For the constriction of the Ear begins while the heart doth not act and ends in the same moment in which the Systole of the heart is completed Finally It is worthy observation that in the Arterial Orifices or outlets of the heart there is no need of the like apparatus to prevent the regress of the expulsed bloud into the Ventricles For after the exit of the bloud and after the greatest part of it is expulsed without the Capillary Arteries it cannot be impell'd back again as well because it is not urged by the force of an Antagonist Muscle of equal strength with the heart as because it is already expell'd out of the extreme Arteries Wherefore Valves of little strength are sufficient here such as is proportionate to the force which the not-intire fulness of the Arteries can make which is very inconsiderable And therefore the Semilunar Valves are far weaker than those Triangular but yet strong enough to hinder the regurgitation of the bloud expulsed by the heart Thus have we run through all the proper actions and offices or uses of all the parts of this incomparable Machine of the Heart in their natural order and found them all to be plainly Mechanic i. e. necessarily consequent from the structure conformation situation disposition and motions of the parts by which they are respectively performed If the Mechanism hath been by us rightly explicated as I am perswaded it hath in the precedent discourse no man has reason longer to believe that the manner of the motion of the heart is a thing to human wit wholly impervestigable Probable it is therefore that when that excellent Anatomist and our worthily honour'd Collegue Dr. Lower said Cùm nimis arduum sit de ratione quâ Cordis motus perficiatur quicquam ritè concipere atque Dei solius qui secreta ejus rimatur motum quoque cognoscere praerogativa sit in eo ulteriùs perscrutando operam non perdam he was out of modesty willing to limit his own curiosity in that particular but not to set bounds to the future disquisitions of other men ¶ ⸫ PRAELECTIO III. Of the Efficient Causes of the Pulsation of the Heart DElighted with the Contemplation of the Structure of this Master-piece of Nature the Heart I have sometimes revolved the Books of the most Celebrated Authors who have professedly written of Architecture and of Hydraulic Engines in search of some example of a Machine that might be at least in a few respects compared with it Of many that occurred that which seemed to me to come nearest in similitude to this inimitable Prototype of Nature was the Hydraulic Mint at Segovia mentioned rather than described by that every way Noble Gent. Sir Kenelme Digby in these words This Engine or rather multitude of several Engines to perform different Operations all conducing to one work is so artificially made that one part of it distendeth an Ingot of Silver or Gold into that bredth and thickness as is requisite to make Coin of which being done it delivereth the Plate it hath wrought unto another that prints the Figure of the Coin upon it and from thence it is turned over to another that cuts it according to the print into due shape and weight And lastly the several pieces fall into a reserve in another room where the Officer whose charge it is findeth treasure ready Coined c. For betwixt this Engine and the Heart I fancied something of Similitude at least in the few particulars following First As the design or end of the former was to Coin mony which is the bloud of all States as well Monarchies as Republicks for the support of the Government so the office and work of the latter is to stamp the character of Vitality upon the mass of bloud for the maintenance of life in all parts of the body and regulation of the whole Animal oeconomy Secondly As the one is moved by a stream of Water so is the other by a current of bloud as to its diastole at least Thirdly As the Artificial Engine was composed of many less Machines each of which performed its proper office by a distinct operation yet all conspired to one common end So the Natural being also complex consisteth of various smaller Machines viz. the Ears Valves Ventricles Musculose flesh Fibres of different orders Chords Columns Papillae c. all which have their peculiar functions and motions yet so combined that they all co-operate to the Vital motion or heat of the bloud and diffusion of the same Fourthly By the Segovian Engine Ingots of Silver were distended to a bredth and thinness requisite to make mony by the heart and its Ears vehemently constringing themselves and repeting their strokes the Silver Chyle or publick revenue of the Animal is attenuated its viscid and grumose parts dissolved the cruder parts concocted and all by conquassation and compression so perfectly commixt with the bloud as to be fit to make good and current bloud Fifthly From the Mint-engine the new stampt Coin was quickly transferred into a receptacle in another room thence to be distributed by orders of the Mint-master From the Heart is the new Coined bloud instantly transmitted into the Arteries to be distributed according to the ordinance of Nature Sixthly As the various parts of the greater Engine were so situate disposed and connected as that if any one of them were by chance displaced broken or hindred in its motion and action presently all the rest must fail to procede in their respective operations and the work of making Coin cease So in the much more subtile and mysterious Machine of the heart if any the least part though but the chord of a Valve be broken or arrested in its motions all the rest will soon be at a stand and the grand work of making the bloud vital be at an end Thus far methought the Parallel held fairly enough and I was not ill pleased with the ramble of my imagination but when I had attempted to
March 28. 1683. ORdered that the Three Anatomic Lectures read on the 19 20 and 21 days of this present Month in the Theatre of His Majesties Royal College of Physicians in London by Dr. Walter Charleton Fellow of the same College be forthwith Printed and Published Tho. Coxe President THREE Anatomic Lectures CONCERNING 1. The Motion of the Bloud through the Veins and Arteries 2. The Organic Structure of the Heart 3. The Efficient Causes of the Hearts Pulsation READ On the 19 20 and 21 days of March 1682 3 IN THE Anatomic Theatre of His Majesties Royal College of Physicians in London BY WALTER CHARLETON M. D. And Fellow of the same College Published by Command of the most Learned President LONDON Printed for Walter Kettilby at the Sign of the Bishops-head in St. Paul's Church-Yard 1683. PRAELOQUIUM CVM non ita pridem Clarissime Ornatissiméque PRAESES mandatum tuum ut ad Saxum hoc anatomicum hîc denuò volvendum me accingerem ad obsequium paratus accepissem mox apud me ultrò citróque agitare coepi quodnam argumenti genus prae caeteris mihi seligerem quo Excellentiae tuae expectationi aliquatenus satisfacere possem simul caeterorum è Doctissimis meis Collegis quorum hîc florem video tota urbe delibatum auscultationi prolixiùs gratificari Plurima quidem tunc temporis anxiae ac in diversa distractae sese offerebant menti nec ad gratiam vulgi conciliandam fortassis incommoda Sed Principum virorum quos in celeberrimo hocce Theatro placidè considentes venerabundus aspicio erudita curiositate prorsus indigna judicabam omnia Tandem verò animo se meo ingessit summum illud necdum etiam Medicorum vulgo satis intellectum Naturae mysterium Sanguinis nempe motus Circularis quo de quidem plerique omnes passim gestiunt garrire paucos tamen reperias qui de causis ejusdem de conditionibus atque circumstantiis quod caput est rei de ratione Mechanica cogitarunt unquam quod seriò dolendum adhuc pauciores existunt qui malè se habentibus consilium daturi respicere soliti sint ad fidissimam illam morbis sive acutis sive chronicis medentium Cynosuram His ego igitur adeò pudendam adeò etiam valetudine adversa languentibus periculosam nunc demum ut excutiam incuriam utque aliquod remedium illorum inscitiae adhibeam mecum statui arreptâ hâc nuper demandatae mihi provinciae occasione de veris hoc est Mechanicis causis quibus in orbem perpetuò sanguis movetur pro ingenioli mei tenuitate inquirere Affulsit quippe animo spei scintillula quaedam ex iis quae ist â de quaestione apud vos dicenda habeo lucis nonnihil afferri posse ad eam penitùs explicandam Quamobrem ne spem alnisse videar inanem permissu vestro primùm agam de Sanguinis per venas ad Cor recurrentis motu rapidissimo itemque de causis istius tantae velocitatis deinde Cordis ipsius conformationem Organicam perscrutabor postremò conabor causas cordis Pulsationem efficientes quae hactenus omnium elusisse videntur Anatomicorum solertiam explorare Haec autem dum viritìm enucleare molior clarioris doctrinae gratiâ demonstrationes aliquot Mechanicas ad institutum meum apprimè facientes ex Alphonsi Borelli omnium quotquot hoc saeculo nostro floruêre Mathematicorum facilè solertissimi scriptis mutuabor omittendo interea caeterorum ferè omnium qui post Harveum nostrum de Circuitione Sanguinis conscripserunt opiniones idque ne aut tempus frustrà conterere aut memoriae vestrae fidelitati diffidere censear Habetis itaque Auditores Aequissimi praesentis mei summam consilii eorumque quae dicere aggredior seriem Quam dum ingenii toto impetu persequi contendam nolo existimetis me mihi veritatis arbitrium arrogare Semper equidem verum quaero quinetiam Senecae illustri exemplo animatus quaero sine inveniendi spe tantum abest ut credam esse me aliis docendis parem Neque etiam adeò sum mihi Suffenus ut cujusquam expectem conatibus meis applausum Novi enim quà m difficile sit diligentiae laudem simul gratiam celeritatis mereri Caeterùm unum illud me solatur quòd fermè rebus suâ naturâ difficillimis venia sit prolixior apud prudentes viros quibus non ignotum quà m sit arduum novis autoritatem obscuris lucem dubiis fidem afferre PRAELECTIO I. Of the Circular Motion of the Bloud and the admirable Effects thereof SO plausible and favourable hath the Hypothesis of various Ferments congenial to and perpetually resident in the various parts principally in the Viscera of Sanguineous and more perfect Animals seemed to many of the Virtuosi of this our inquisitive age that they have not doubted to ascribe to them a powerful energy and necessary influence in all the divers Motions all the Mutations all the Concoctions all the Secretions and other operations instituted by Nature in such Animals either for the conservation of them in their single beings or for the propagation of their respective Species Nor is it easie for us to name any particular function any action though really and manifestly Organical which the Sectators of this Hypothesis will not presently attribute to some peculiar Ferment lurking and operating in the part by which that action is done and conferring forsooth somewhat of efficacy toward the doing of it as if the organical constitution of that part were insufficient to the function and uses for which it was designed without the help and cooperation of a Specific Ferment or as if the whole Animal Oeconomy depended upon no other Harmony but that of numerose Fermentations In a word they make them only not Omnipotent As Heraclitus the Ephesian dreamed 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 that all places are full of Spirits and Daemons that presided over human actions So these Gentlemen imagine all the parts of Animals to be full of I know not what Spiritual Ferments that by occult influence regulate and diversifie their functions And this Comment many have endeavoured to assert by their Writings with as much confidence as if the verity of it were evident either from cogent reasons or by Autopsy when in truth they are no more able to prove by solid Arguments or by sensible demonstration the existence of many of their imaginary Fermentative liquors or Spirits in the dissected parts to which they are pleas'd to consign them than Heraclitus was able to exhibit to mens sight any one of his Daemons I say many of their imaginary Ferments I do not say any Because the Acid Phlegm found in the Stomachs of various Animals may perhaps so far emulate the nature of a Ferment as to deserve the same name For being endowed with an incisive penetrating and dissolving faculty 't is not improbable but it may conduce to the dissolution and liquation of
is necessary to its perfection and vitality especially if we farther consider that the same opinion is also Inconsistent with the Wisdom of Nature Whose custom always is to institute the most direct and compendious methods for the attainment of her ends nor ever to use many instruments where one may suffice to effect what she hath design'd abhorring to multiply things without inevitable necessity To this her admirable Wisdom then it is injurious to imagine that when she had ordained in the bloud a certain placid regular and benign motion by which all the heterogeneous ingredients or constituent parts of it should be so agitated among themselves as by their mutual conflict to produce an alternate expansion and contraction from whence a vital heat results and upon which original life continually depends she should notwithstanding institute a second intestine motion to be at the same time in the same subject performed viz. a Fermentation which seems unnecessary at best and which probably might not only hinder and impugn but also destroy the former A Fermentation would indeed raise a tumultuous agitation of the same dissimilar elements of the bloud but such as would be violent irregular and of a far different manner from the Vital Mication But not to insist now upon the manifest disparity of these Two Motions which may more opportunely be collected from what I shall soon say of the genuine and true one let it be supposed at present that both may operate in the same manner and produce the same effects in the bloud as to the attenuation and comminution of the grosser viscid and unagile parts and the facilitation of the expansive efforts of the Spiritual volatile or elastic yet still it will remain to be inquired why Nature should institute Two Motions where either of the two might singly do her work as well if not better If therefore any defendent of this opinion which I have here en passant impugned shall vouchsafe so far to illuminate my gloomy understanding as to solve this Problem I shall acknowledge the favour and recant my opposition of it Mean while I will suspend the farther consideration thereof and now address my self to the more important part of my present province the true and undoubted Motions of the Bloud viz. the Mication and the Circulation by both which though divers in their origines and kinds yet mutually helping each other and conducing the one to the accension as it were of original life the other to the distribution of influent life the bloud is perpetually moved in the vessels that contain it By the FORMER of these the vital spirits or if you please the elastick particles of the bloud now passing through the Ventricles of the heart from their own natural force or expansive energy endeavour to expand or unbend themselves while the grosser and viscid parts resist that endeavour to expansion by compressing them Hence instantly and by natural necessity arises a certain Colluctation or mutual striving betwixt the expansive motion or endeavour of the Vital Spirits on one part and the renitency of the grosser parts of the bloud on the other And from this Colluctation an actual heat is quickly excited or kindled in the bloud actual heat being nothing else but an expansive luctation of the particles of the body or subject in which it is as I professedly labour'd to evince from various instances and a strong chain of propositions when I first had the honour to sit in this Chair Moreover because this expansive luctation is not violent nor unequal nor irregular nor consequently noxious or hostile to the nature of the bloud but on the contrary always in statu Naturae moderate equal regular amicable and tending not only to the conservation of the bloud but also to the exaltation of all its faculties and operations and because it proceeds from an internal principle from the energy of the vital spirit contain'd in and ruling the bloud or if this be more intelligible from the Elasticity of the aereal particles commixt with the bloud therefore the brisk motion or heat thence resulting is also vital For in that very expansive motion of the bloud doth the formal reason of life originally consist which Theorem also I have formerly in this place endeavour'd to explicate and establish This admirable motion from the various notions or conceptions which Learned men have formed of it in their minds hath acquir'd various names By some it is call'd motus sanguinis intestinus sive spontaneus because it arises from an internal principle the expansive endeavour of the spirituose or elastic parts of the bloud and to â—â—â—tinguish it from the circular motion which is impress'd by an external Movent viz. the Heart By others Motus fermentationis vitalis from the similitude they fancyed between it and common fermentations but improperly for the reasons by me just now alledged By others again motus oscillatorius from the resemblance it hath of the Oscillation or swinging of a Pendulum whose motion describes a Cycloid and by others Micatio sanguinis the panting or reciprocal expansion and compression of the parts of the bloud Of these denominations the two last seem to me more fully and emphatically than the rest to signifie the nature and manner of the thing denominated as equally comprehending the double motion in a single appellation Wherefore I intend hereafter to use these promiscuously when there shall occur to me any occasion of mentioning the same motion Mean while I proceed to The LATER motion the CIRCULATION of the Bloud the most noble and most useful of all modern inventions first obscurely hinted as some think by Cesalpinus but afterward with prodigious sagacity most exact judgment and happy diligence investigated and with such convincing evidence demonstrated by our immortal Dr. Harvey that now the verity thereof is no longer doubted of in the world I wish the same were as well understood as it is generally acknowledged and lest I be thought only to wish this excellent knowledge and of so great importance to Physicians I will now again do my best devoir to explain so much of the mystery as I my self have formerly left not sufficiently explicated omitting to reoire what is vulgarly taught in the Schools and Books of Anatomists and touching only those things which have been either pretermitted or not rightly explicated by others concerning the Causes Mechanical modes and circumstances of this life-conserving motion There intervenes ye know a double pause or respite which by Anatomists is call'd perisystole cordis between the two contrary motions of the heart one betwixt the diastole and the systole another betwixt the systole and the diastole and this of absolute necessity because it is impossible that the same body should perform two contrary motions without a morula or space of time how short soever be interposed betwixt them Ye know also that the force impelling the bloud which is the Compression of the heart doth not
act continually but interruptedly or per vices short and almost isochronic or equal quiets interposed So that the bloud express'd by the heart doth not flow thence in a continued course as rivers and fountains do that are without intermission carried on by the weight of their waters but gush forth and stop alternately though this vicissitude be exactly regular and proceeds in a constant order Now these things considered it may seem consentaneous to conclude that the motion of the bloud cannot be continuus since two pauses or quiets are interposed betwixt every two pulsations or Systoles of the heart during each of which the motion ceases but on the contrary ought to be esteem'd and call'd an interrupted and mixt motion And yet notwithstanding the verisimilitude of this conclusion I doubt not to lay down and expose to your examination this First PROPOSITION That the bloud is carried in a round through the body of an Animal in a truly continued and never interrupted motion This perhaps may sound like a Paradox but that shall not a-whit discourage me from asserting it while I remember that remarkable sentence of Minutius Felix in Octavio Inest in incredibili verum in verisimili mendacium Though it be true and evident that the heart doth not in the time of its pauses express any Bloud into the Arteries yet it is not true that the bloud contain'd in the Arteries in the Viscera in the habit of the body and in the Veins doth at the same time stagnate and stop its course but on the contrary is always carried on in its journey though with unequal velocity First the Verity of this appears in the Arteries For the afflux of bloud from the heart being wholly intercepted either by a Ligature applied to the aorta at its original or by cutting out the heart it self as is commonly done in Frogs and Vipers we see that nevertheless the bloud wherewith the Arteries were fill'd is by degrees squeez'd out so that they are soon after left altogether empty And doubtless this exinanition of the Arteries happens because they by their own spontaneous motion constringe themselves and contracting their Circular Fibres express the bloud into the habit of the parts and are at the same time compress'd also by the contraction and tension or the peristaltick motion of all the Muscles of the Body From the observation of this vulgar Phaenomenon viz. the emptiness of the Arteries in dead bodies the Ancients perhaps took occasion to believe and teach that not bloud but only Vital Spirits are contein'd in the Arteries Secondly this appears also in the Veins For that the bloud doth continually flow on in them likewise not only when it is urged forward by the Arterial Bloud pursuing it but even in the time of the hearts pauses is evinced from this that then the bloud runs on through the trunk of the Vena cava to replenish the right Ventricle of the heart But why do I mis-spend time in alledging reasons to prove a truth that is manifest to sense in Phlebotomy no sooner is a Vein open'd than the Bloud flows forth with a swift stream and while the wound is open continues to flow without pauses or interruption which is a demonstration of the thing proposed viz. of the continual motion of the Bloud in the Veins Being thus assured of the effect let us proceed to investigate the Causes which are not equally evident nor can we hope certainly to solve this Problem without enquiring the Mechanical reason of the continual motion of the Bloud through the Veins This therefore I will now attempt to do That Nature hath instituted no immediate Communication betwixt the Capillary Arteries and the Capillary Veins per anastomôsin is manifest to sense and now acknowledged by all Learned Anatomists and therefore it cannot stand with reason to imagin that the Bloud in its Circular course is emitted immediately out of the Arteries into the Veins these vessels being separate And though we opine that there is some secret communication betwixt the extreme Orifices of the Arteries and those of the Capillary veins by the intermediate Spongy substance of the flesh Viscera and glandules or by the Cribrose substance of the Bones as by the Pores of a Pumice stone yet we are still to seek by what motive force the bloud may be carried on from those intermediate Porosities and insinuated into the veins First because 't is consentaneous that the impulsive force whereby the Systole of the heart squirts the Bloud into the Arteries is by degrees weakned and at length languid in those streights of the extreme vessels and of the intermediate Porosities Secondly Because the Orifices of the Capillary veins cannot continue always open and dilated their consistence being not hard and bony but membranose soft and slippery so that they are apt to be closed by conniving and consequently to hinder the ingress of the bloud newly arrived Thirdly Because here we can have no recourse to the compression of the Viscera and the Muscles whereby the bloud should be squeez'd into the Orifices of the Capillary veins for we see that the bloud is suckt up by the Capillary veins not only when the Muscles are invigorated and upon the stretch but also when they are quiet and relaxed and do not exercise their compressive power as is most evident in sleep when the Circulation proceeds without intermission This is confirm'd from hence that in the Brain in the Medullary substance of the bones where no compression can be admitted the Capillary veins receive the bloud as freely as in the softer flesh it self Seeing then that the effect cannot be denied viz. that all the bloud effused out of the Arteries is after absorpt and carried off by the Veins to be brought back again into the heart and seeing also that this is not effected by way of Attraction there being no such thing as attraction in Nature as I have more than once elsewhere proved we are compell'd to assert that the Bloud is imbibed by the Capillary Veins for the same reason and by the same Mechanick action by which Syphons Sponges Filtres Chords and all Porose bodies are penetrated by water with which they are moistned which power is no other than the gravity of the fluid it self which is augmented by the impetus of its proper motion and by the impulse communicated to it from external force So the motive force of Gravity which the bloud can want no more than water can when it finds the small chanels of the Capillary veins open for they can never be so closely constringed by the flagging and connivency of their thin membranes as to leave no entrance for a fluid as appears in the Pores of Ropes how hard soever twisted must of necessity overcome the weak resistence of the streights in all Filtres and Porose bodies and consequently the bloud may be insinuated into the Capillary veins by a Mechanic action like that of Filtration If this proposition
be true the greatest difficulty occurring in the whole mystery of the Circulation of the bloud is now at length solved The bloud having in this manner passed the aforesaid streights and entred into the Canales of the small veins by the same motive force whereby it was insinuated for such an ingress is not possible without motion may be advanced a little farther in its way by its proper force and by external force and also by the impulse of the new bloud following behind as we see water suckt up by a Filtre to be carried on to the end of the list Afterward because many small veins meeting together make one wider ductus or pipe and because in this larger pipe the former impulsive force of necessity grows more and more languid and faint by degrees and by consequence the motion of the bloud is retarded therefore it stands in need of some auxiliary forces to be carried on the rest of its journey These are First the force by which the Circular Fibres of the Veins that naturally have a peristaltic virtue contract themselves always after they have been stretch'd as all Nervose and other tensile bodies are observ'd to do Secondly The Compression of the Veins by the weight of the Circumambient air or Atmosphear and the Elastic virtue of the air inspired Thirdly The Tonic motion of the Muscles when they act together with the various motions of the Viscera and of humours discurrent through the body all which more or less compress the veins Now that the manner how this compression promotes the continual decurse of the bloud in the Veins may be the more fully and clearly understood I will take liberty to lay down this Second PROPOSITION That by the artifice of the Valves the Compressions of the Veins protrude the Bloud toward the heart with a motion doubly swifter not indeed in a continual flux but with little pauses interpos'd and with unequal velocities We here behold in the Crural vein slit open from end to end certain Valves placed at unequal distances in the inside of the Vein which for demonstration sake are accurately represented in this Figure expos'd to sight These Valves ye see are nothing but half pockets of a membranose substance or little bladders affixt to the sides or walls of the Vein and resembled by AONMP and BONQR They are found sometimes single sometimes in pairs placed one opposite to the other and laterally touching each other as at NO the convex tops of which pair respect the Capillary beginnings of the Veins beyond HL but the Orifices of their cavities PO RO open toward the heart have respect to the parts IK Now I am to demonstrate that from this structure and situation of the Valves it is necessary that the Bloud be protruded toward the heart Imagine then that the same portion of the Vein HMQL is replete with bloud and because by the circular Fibres of the Vein itself and by the ambient Muscles and perhaps also by the gravity of the Atmosphear one part of the Vein is constringed after another all along it must be that the lateral walls ST come nearer to each other toward V and then the Vein so girded will lose its Cylindrical form and be turn'd into two little funnels HVL MVQ which are less capacious than the former Cylinder and therefore the bloud which was contained in the spaces VHS and VLT will be expell'd out of the Orifice HL but the remaining quantity of bloud contained in the spaces VSM and VQT will be squeez'd without the Orifice MQ toward IK It appears then that from the above-mentioned compression of the sides or walls of the Vein the bloud is express'd in equal quantity to the opposite parts and this would certainly happen if the Valves were removed But because to the walls of the Vein within MP QR are fastned two Valves it is necessary that the bloud impuls'd by a compression made in ST be forced through the narrow chink NO because the yielding fluid contain'd in the cavities of the Valves and urged by the advenient bloud is constringed and thrust out of them and then instantly the sides of the Valves that before touched each other NO receding one from another leave an open way by which the flux of bloud coming on from MSTQ may be insinuated and pass forward beyond AB Again after the bloud hath passed the confines of the Valves PO RO there necessarily follows a restriction of the little chink NO For the bloud it self must by reason of its heavy bulk and fluidity fill the little baggs of the Valves and so their soft and pliable sides being dilated till they mutually touch ought closely to shut the rimula NO Moreover because the Vein is not constringed in all its parts at the same time but part after part successively therefore after the bloud is transferr'd beyond the Valves within the little funnel ABCD there follows a constriction of the walls AD BC in the same time in which ST is not constringed And because by reason of the close shutting of the rimula NO half the bloud that was contain'd in the spaces EAG FBG cannot flow back toward AB finding the obstacle AOB fill'd with bloud and retain'd by the Valves it is compell'd with a reflex motion like that of a Tennis-ball rebounding from the wall to flow toward DC and since by the same compression the Bloud that was contain'd in the spaces EDG FCG is protruded beyond DC therefore a double quantity of bloud is in the same time in which the compression is made expelled through that same aperture DC but when a double quantity of a fluid is in the same time emitted at the same Orifice it must run out with a double Velocity Thus is our Proposition verified And as to single Valves from what hath been said of the use of double it may easily and genuinely be inferred that they also help to promote the course of the bloud though but half so much as the double Wherefore Natures wisdom is admirable in placing single Valves both at less distance one above another and for the most part where the Cavity of the Vein is a little narrower or where a less Vein laterally exonerates it self into a greater in both which cases the necessity of this demonstrated acceleration of the motion of the Bloud seems to be less In the trunk of the Vena cava no valves are found as well because of its ample Cavity as because of its contiguity to the trunk of the great Artery by whose pulsations it cannot but be somewhat compress'd and consequently the Bloud flowing through it proportionately promoted In the Iugular veins also none have yet been observed probably because in them the bloud descends swiftly enough from its own weight and fluidity In small veins they are not placed unless in the Coronary veins of the heart just at the place where they empty themselves into the right Ventricle of the heart and of these
too the use is not to promote the course of bloud of which there is no need in so small a circuit but only to prevent the reflux of it out of that Ventricle in the systole of the heart as appears from their situation and from their conformation Nor are any found in the Arteries in which the bloud with mighty force impulst by the constriction of the heart and of the Arteries needs no additional machine to accelerate its motion except those that are placed in the inlet and outlet of the left Ventricle to obviate the regurgitation of the bloud into the arteria venosa and out of the aorta into the left Ventricle and the two very little Valves sited in the two Coronary Arteries at their origine from the aorta to prohibit the regress of the bloud into the aorta ¶ ⸪ If this Artifice of the Valves affixt within the veins be so necessary to promote the reflux of the bloud toward the heart certainly he that first discovered them deserves to be remembred with honour But who was that fortunate man Fabricius ab Aquapendente put in his claim to the glory of the invention as wholly due to himself in these very words De his itaque ostiolis nempe venarum locuturus subit primùm mirari quomodo ostiola haec ad hanc usque aetatem tam priscos quà m recentiores Anatomicos adeo latuerint ut non solùm nulla mentio de ipsis facta sit sed neque aliquis prius haec viderit quà m Anno Domini Septuagesimo quarto supra millesimum quingentesimum quo à me summa cum laetitia inter dissecandum observata fuere But Padre Fulgentio professly ascribes the invention to that prodigy of Wisdom Learning and Virtue Padre Paolo the Venetian at the same time openly accusing Aquapendens of disingenuous arrogance and theft for challenging to himself the honour of having first discovered the Valves to which he had no right and for stealing the glory due only to Father Paul The sence of his impeachment is this The whole Tractate concerning the Eye which passeth under the name of Aquapendens or at least so much of it as contains new and rare Speculations and Experiments is the work of Padre Paolo whereof I have had speech with some that were eye-witnesses and knew that a due part of the praise was not attributed to him that deserv'd it all But much more in another matter of more moment which was the finding out of those Valvulae those inward shuts or folds that are within the Veins Of which argument I do not find that any either ancient or Modern hath made mention because it was a thing unthought of till these times when Aquapendens moved the question in a publick Anatomy But there are still living many eminent and Learned Physicians among whom are Santorio and Pietro Asselineo a Frenchman who certainly know that it was no Speculation nor invention of Aquapendens but of Padre Paolo Who considering the weight of the bloud grew into an opinion that it could not stay in the Veins except there were some bunch to hold it in some folds or shuttings at the opening and closing of which there was given a passage and necessary Aequilibrium to life And upon his own natural judgment he set himself to cutting with more accurate observation and so found out those Valves c. Having thus faithfully recited the Pleas of these two great men I leave it to you to decide the controversie and to fix the Laurel on the head of which of the Competitors you please For my part if my judgment were considerable I should declare my self on Padre Paolo's side as to the invention and allow to Aquapendens the honour of being the first that by writing made the thing known to the world Understand me I beseech you only of the Valves themselves not of the true use of them which neither Aquapendens nor the Father had the happiness to discover Not Aquapendens because of the two uses by him assign'd to these Valves which he most improperly named Ostiola namely the corroboration of the Veins which might otherwise be by the bloud every where distended and broken into varices and the retardation of the bloud in the Veins that so all parts of the body might have time to take in their due shares of bloud for their nourishment and not have their meat forsooth snatcht away before they have fill'd their bellies of these two mighty uses I say neither is true and both are raised upon this Supposition that the course of the bloud is out of the greater and superiour Veins into the smaller and inferiour which is most evidently false even by the testimony of the sight But lest I be thought either not well to understand or to misrepresent his meaning I am obliged to recite his own words Nam cùm in varicibus in quibus aut laxari aut rumpi Ostiola par est plus minusve dilatatas semper venas conspiciamus dicere proculdubiò tutò possumus ad prohibendam quoque venarum distensionem fuisse Ostiola à Summo Opifice fabrefacta c. Thus far then I have done him no wrong He proceeds Erat profectò necessaria Ostiolorum constructio in artuum venis quae non exiguae sed vel magnae vel moderatae sunt magnitudinis ut scilicet sanguis ubique eatenus retardetur quatenus cuique particulae alimento fruendi congruum tempus detur quod alioqui propter artuum declivem situm confertim ac rapidi fluminis instar in artuum extremitates universus conflueret ac colligeretur idque tum harum partium tumore tum super positarum marcore Here also I have faithfully interpreted his words and ye see that he thought the contrivement of the Valves necessary to retard the motion of the bloud because he took it for granted that the bloud descended through the greater Veins into the less grossly erring in both opinions For that the former is false we have seen demonstrated from the construction and situation of the Valves themselves and that the latter also is false and absurd is known to all who understand any thing of the Circulation of the Bloud To these errors he hath in the same Page added a third much more extravagant which is that the bloud is by a flux and reflux perpetually carried forward and backward in the Arteries For attempting to give the reason why Nature hath framed no Valves in the Cavities of the Arteries he saith Arteriis autem ostiola non fuêre necessaria neque ad distensionem prohibendam propter tunicae crassitiem ac robur neque ad sanguinem remorandum quòd sanguinis fluxus refluxusque in Arteriis perpetuò fiat It appears then that this famous Anatomist who in many other things deserved well of the Commonwealth of Physicians had no just title to the honour of having first invented the true and genuine use of the Valves
of the Muscles of the Guts Stomach Tendons Membranes and the like Fibrose parts naturally resist distraction and have a power of contracting themselves after extension Yea more we see that all Fibres even in their natural posture are somewhat upon the stretch for when they are cut they instantly shorten themselves toward both ends which would not happen if they had been constituted in a middle state betwixt laxity and extension as a Bow unbent is quiet suffering neither contraction nor distraction of its parts Now if all Fibres even in their natural state suffer some degree of stretching certainly when the Arteries are replenisht with bloud their cavity must be dilated and in the dilatation of their cavity their transverse or circular Fibres must suffer much more stretching than they did before And because to this dilatation of the Arteries a constriction immediately succeeds which is not possible to be effected without an abbreviation of the circular Fibres of the Arteries and because that abbreviation or contraction is connatural to the Fibres themselves therefore it is impossible that the Arteries after that violent stretching caused by their repletion and turgency should not exercise by natural necessity that mechanic power they have of contracting themselves by vertue of their circular Fibres girding them inward and equally impossible that the Arteries should so contract themselves without expelling at the same time out of their Orifices the bloud that dilated them Whence it appears beyond dispute that the spontaneous constriction of the distended Arteries is the cause of the expulsion of the bloud out of them into the substance of the parts contrary to their opinion who ascribe this expulsion only to the Systole of the heart ¶ ⸪ The natural method of acquiring Science ye know is to begin from things more known and then to advance to things less known to procede from effects to their causes Seeing therefore that we are now certain that the bloud in Animals is carried by a perpetual circular motion through all parts of the body our next business is to enquire what are the Causes of this admirable motion as well the final as the efficient I begin from the final it being a question worthy our consideration why or to what end Nature all whose counsels and actions are ordained by an infinite wisdom hath instituted this rapid Circulation of the bloud Constant it is even from common experience that whenever the bloud is quiet or ceases from motion whether within or without the body of an Animal the red and grumose part of it soon curdles and is separated from the serose or albumen and so the constitution or contexture of it is dissolved and corrupted whereas on the contrary while the bloud continues in perpetual motion within its vessels in the body of a living Animal so long the ordinate mixture of its elements due temper and vital constitution of it is conserved for mechanical reasons in our ensuing discourse to be explained It seems then that such a mixture of the constituent parts of the bloud upon which the vitality of it doth necessarily depend cannot be otherwise conserved than by a continual agitation and concussion made in the vessels first by the heart with strong force impelling the bloud through the Arteries then that impulsive force languishing by filtration in the spaces intermediate betwixt the Arteries and Veins next in the Veins by the constriction of their circular Fibres by the compression of the Muscles and the Viscera and the inspired air All which compressions would not suffice were not Valves placed commodiously within the Veins by which the motion of the bloud is accelerated and a farther conquassation of it made And here we meet with a fair occasion to reflect upon the mutual Anastomôses of the Capillary Veins and the infrequent distribution of Valves in one and the same Vein for both these contribute also their proportions toward the end now under our disquisition For the texture of the Veins being indeed lax and soft yet such as may by virtue of their circular Fibres be constringed and contracted hence it is that by the bloud regurgitating in those tracts of the Veins that have no Valves by the great quantity and force of its regurgitation or recoiling the lowest part of the Vein is much dilated and on the contrary the highest part is contracted So that the bloud being by this reflux though inobservable agitated and conquassated may revive its due commistion and conserve its vital constitution It appears then the defect of Valves also hath its use Within the cavities of the Arteries as I said before no Valves are placed because the grand force by which the bloud is impell'd through them is more than sufficient to conquassate and commix it by wedging in as it were the more fluid albugineous particles among the red grumose particles that from both sorts comixt per minimas moleculas as they say and yet mutually reluctant the Vital Mication or Oscillatory intestine motion of the bloud may be continued So then here is neither need of nor place for a Fermentation Now from the consideration of these things premised I conclude that the Circulation of the Bloud was instituted for the conservation of its requisite temper and vital constitution Which was to be inquired and which leads us to The admirable effects and benefits arising to the Animal Oeconomy from the same Velocity of the Circulation of the Bloud Which being certainly so great that the whole mass of bloud runs its circular race in the twentieth part of an hour or thereabouts even in a sedentary and sedate man as hath by many been demonstrated from the quantity of bloud commonly contein'd in the body from the number of Pulses made in an hour and from the quantity of bloud exprest by every pulse of the heart and we having already seen what advantage redounds to the bloud it self from this velocity our curiosity spurs us on to enquire also what other scopes or ends Nature may probably be conceived to have proposed to herself when she instituted this so rapid motion or what emoluments and benefits from thence redound to the Oeconomy of the whole body Of these the first seems to be this that in every pulsation of the heart a great quantity of bloud is effused and protruded out of the Capillary Arteries into the habit of the parts for their refocillation by influent life of which I have formerly discoursed copiosely in this place For by how much swifter the motion of any liquor or other fluid through a pipe or canale is so much a greater quantity of it is in equal time effused at the Orifice thereof as hath been ingeniously demonstrated by B. Castellus and therefore the bloud is like a full and rapid torrent impelled into the Pores of the flesh and Viscera The second is the energy of the stroke with which the bloud projected by the heart dashes against the same extreme parts which energy is
composed of the degree of velocity and of the quantity of bloud impulsed as that excellent Mathematician Io. Alphonsus Borellus hath fully demonstrated By this stroke it is that the newly emptied and conniving porosities of the Muscles and Viscera are forced open and replenished with the impulsed bloud that communicates to them vital heat and fresh vigor and that the torpid useless and excrementitious particles there remaining are protruded and expelled partly through the pores of the skin partly through vessels destined to their transportation and expulsion So that by this rapid rushing in of the bloud nature attains to not only a reviving of the solid parts of the body but also to the expurgation of the bloud it self from its unprofitable and excrementitious parts in the Emunctories ordained for that office A third advantage is that by the same rapid velocity of the bloud and its vehement intrusion into the narrow meatus of the parts the current thereof dislodges rinses away and carries with it many other amoveable particles of various kinds Saline Sulphureous c. principally the reliques of the nutritive and nervose juices brought thither from the brain which though unprofitable now to the refection and invigoration of the parts in which they were left may yet be of some use to recruit and conserve the Crasis of the bloud and to expedite the secretion of its excrements This artifice of nature we may more easily comprehend by observing that the foreign particles now mentioned are extricated and rinsed away by the bloud not in ample vessels but after the egress of the bloud out of the Capillary Arteries in the intermediate spaces betwixt them and the Capillary Veins where end innumerable small Canales some of which bring in the nutritive and nervose liquors others export the superfluous and less profitable particles of them which small pipes are like the Capillary roots of plants almost every where disseminated into the fleshy parts into the Viscera and most frequently into the glandules And this seems to be done to the end that so many particles of these spiritual and noble juices being rinsed away by and commixt with the the bloud may advance and conserve the due consistence and constitution of it Now of these three considerable benefits no one seems to me possible to be attained otherwise than by the perpetual and rapid motion of the bloud Wherefore I am not destitute of a rational ground to support my conjecture that for these ends Nature thought fit to institute the swift motion of the bloud in its Circulation ¶ ⸪ But what may we conceive to be the reason that induced Her to institute also so multiplied a repetition of this course of the bloud through the same ways A River we know though the water be in a continual flux is yet still the same river because the elapsed parts are continually succeeded by new waters coming on with the same degree of speed to supply it But to maintain this perpetual succession and supply upon which the identity of the river necessarily depends there is required either an immense quantity of waters from a spring to feed the current or the same elapsed water must be brought back again to the fountain whence it flowed that so by perpetually reiterated circuitions the course of the river may be conserved which otherwise would soon fail and cease We are then no longer to admire that Nature having designed to bring the river of bloud with a most rapid course through the whole body of an Animal for the various ends above explained and resolved to make that course perpetual during the life of the Animal made use of the same expedient viz. to repete the circuition of the same bloud without intermission For the whole mass of bloud commonly found in the body of a man not exceding 20 pints and that quantity not sufficing to maintain the course above 5 or 6 first minutes of an hour lest the current might cease and so life also fail it was necessary that the circulation of the same mass of bloud should be continually reiterated for the conservation of life Besides this necessity there are many admirable uses and advantages which Nature brings to an Animal by often repeating the period of the circuition of the bloud through the same ways For if the Circulation were not in this manner reiterated the bloud could not be defaecated from its biliose excrement in the Liver nor according to the vulgar opinion from the matter of Urine in the Kidneys nor could either the Chyle be commixt with the bloud in the heart or the Lympha be brought to temper and dilute it in the Veins nor could various other operations necessary to the Animal oeconomy be performed All which it were not difficult for me to deduce from this repeted circuition of the Bloud if the shortness of the time appointed to me for the administration of my present province did not oblige me to pass by all collateral disquisitions and to peruse my principal Theme the Motion of the Bloud From the final causes of which I will therefore in a direct order procede to the Efficient ¶ ⸪ PRAELECTIO II. Of the Heart and its Pulsation TO measure the Divine Wisdom elucent in every Organ of an Animal by the short line of human Reason is indeed extreme folly and yet I doubt not to applaud and follow the counsel of Erasistratus who as Galen relates advised Physicians to solve all the actions naturally done in the body of an Animal by Mechanic Principles so far at least as the dim light of my limited understanding may serve to guide me in my researches For not to depend upon the authority of Plato who said 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 that God always works by Geometry or of his greatest disciple Aristotle who from thence called God 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 the Mechanic of the world we have the greater authority of the Sacred Scripture itself that God hath framed all things in number weight and measure Whoever therefore intends with due care to study any part of his works must therein chiefly consider number weight and measure i. e. the Mechanism of it otherwise in the end he will find his mind rather swell'd with opinion than fill'd with knowledge Why then may not we who are Christians as well as Natural Philosophers take those parts of an Animal to be Machines or Engines which evident reason and chiefly sense shew to be such or who hath prohibited us to investigate the formal reason and manner of their operations It is not more certain that no mortal can know enough of Gods works than it is that the more we are able to discover of his wisdom power and goodness discernible in the mirrour of his Creatures the more we shall find our selves obliged to admire love and adore him Equally certain it is also that no kind of devotion is more acceptable to him than that which procedes from knowledge of his infinite
Perfections and that the Sacrifice of Praises offer'd up to Heaven from the mouth of one who has well studied what he commends are more sutable to the Divine Nature than the blind applauses of the ignorant Wherefore since we are now come to the Efficient cause of the before described motion of the bloud which our senses plainly shew and all learned Anatomists acknowledge to be the Pulsation of the heart and since it is equally manifest that this Pulsation is an action intirely Mechanick let us attentively contemplate and consider the Mechanism of the heart from whence that action necessarily proceeds For the true reason and manner of the Pulsation being known our disquisition of the motion of the Bloud will be complete and we shall so much the more admire and laud the skill of the Divine Engineer who contrived and made the Machine of the heart of so small a bulk and yet of so stupendous power and force Nor ought we to despair of finding what we search for because though the Heart of man be to us inscrutable as to its 〈◊〉 thoughts and reserves it seems not to be inscruâ—â—â—â—e as to its Fabric and Conformation I will therefore endeavour to explain the structure of it That the Heart is a Muscle of the same nature with the Muscles of the Limbs is apparent to the sight and will be more apparent if the Carnose Fibres of it be plumpt up by boyling For then we may plainly perceive that it is composed of robust fleshy Fibres of the same Prismatical Figure of the same colour and consistence and tenacity as the Fibres of other Muscles have and therefore the Fibres of it are in like manner inelongable and resist distraction they as those of other Muscles spontaneously contract themselves after extention may be swell'd and acquire hardness when they act in the Pulsation of the heart So far the resemblance holds But yet the Fibrose constitution of the heart differs from that of all other Muscles in this that the flesh of the heart is firm hard uniform of a deep ruddy colour nor are the prismatic columns separated from the little membranes and innumerable Tendinose Fibres as the Fibres of the other Muscles are Besides the disposition and configuration of the Fibres of the heart is extremely divers from that observed in all others For here the Fibres are neither direct nor parallel among themselves but curve and spiral and in wonderful manner variously interwoven and implicated not by a Texture like that by which Wicker Baskets are made as Vesalius imagined them to be but disposed with a more admirable artifice For immediately under the outward membrane investing the heart from the Basis of the heart and from the Circular Tendinose Orifices of it in which the Vena Cava and the Vena Arteriosa are terminated as also from the beginnings of the aorta and arteria venosa is propagated a stratum or Layer of Carnose Fibres which are almost aequidistant among themselves and tending directly from the Basis toward the Cone of the heart where variously inflected and contexed they are reflected toward the Cavities or Ventricles within the â—â— volutions and mutual intersections seem to give to the heart its circular and Conical Figure in which it is not resembled by any other Muscle whatsoever are disseminated in great multitude spriggs of Nerves derived from the interior branch of the Eighth pair properly named par vagum all which passing betwixt the arteria pulmonaris and the aorta first bestow many smaller surcles upon the Auriculae on each side and then implant themselves into the Fibrose substance of the heart in divers places The manner of which their implantation is plainly visible in the heart of a Calf Lamb or other new born Animal while it is yet warm But because in things Anatomic the Eye is a better instructor than the Ear I have caused to be accurately represented in this Figure the whole System of Nerves pertaining to the Heart and its Ears to help both the understanding and memory of younger Students for whose sake chiefly Lectures were at first instituted in this College FIGURE III. In this Figure AA AA represent the Nerves of the Eighth pair cut off which though derived from the same origine are yet in a man after they have passed out of the Skull divided into two Trunks of which the exterior denoted by BB is call'd the Intercostal branch because in its descent toward the parts of the lower belly it receives many Spriggs of other Nerves shooting forth between the ribs from the Spinal marrow as auxiliaries and the interior named par vagum from its various windings and turnings first distributes divers surcles in its passage downwards to the heart then subdividing itself into more threads is disseminated into the Viscera contein'd in the abdomen DD The plexus of the former or intercostal branch call'd ramus Cervicalis because in man it is sited on each side in the middle of the neck EE The plexus of the Nerves of the later branch or par vagum F The Cardiac plexus in which are terminated smaller Nervose tendrels GGG arising on each side from the plexus cervicalis of the intercostal nerve HH Surcles of a conspicuous nerve shooting forth from the plexus of the par vagum and terminating itself in the plexus Cardiacus II Many nervose productions from the plexus of the par vagum distributed to the Pericardium to the vessels conjoin'd to the heart and to the ears of it K Remarkable surcles of nerves from the plexus Cardiacus which passing betwixt the arteria pulmonaria M and the aorta N are terminated in the substance of the heart LL Two considerable Nerves sent from the par vagum to the heart which are variously combined as it were by mutual inosculation both among themselves and with Nervose branches issuing from the plexus Cardiacus to the end doubtless that both might be strengthned by that union These seem to be the principal of all Nerves pertaining to the heart and most likely to convey influence from the brain to the heart whatever that influence be to invigorate it and maintain it in perpetual motion probably by supplying the heart with succus nutritius in great plenty OOOO The Musculose substance of the heart into which the said Nerves are inserted In this manner hath Nature furnished the heart of man with store of Nerves thereby providing for its strength and continual motion Nor hath she much diversified her work in the hearts of Brutes For all the difference that hitherto hath been observed in them as to the Nerves is only this that beside the productions that come from the Nerves of the Eighth pair in a place somewhat higher and are distributed to the heart in most Brute Animals there are moreover very many spriggs shooting from the same Nerves where they pass above the heart and receive as auxiliary supplies nervose surcles passing betwixt the ribs from the Spinal
the Muscle of the heart is composed of the same constituent parts with all other Muscles viz. of bundles of carnose Fibres of the same Tendinose and Contrahible substance of the same prismatic Figure in the same manner disposed Layer upon Layer bound down by mutual contexture in the same manner interspersed with branches of Nerves fastned to Tendons and enlivened by bloud irrigating them out of the Arteries In a word there is no sensible difference or disparity the Figure of the whole heart excepted which yet doth not diversifie the Organic nature of it no more than the diversity of Figures among other Muscles doth make them of a different nature Then if we consider the action of both the Heart and all other Muscles we shall find that as well the Fibres of the heart as those of all other Muscles act by contraction of themselves If we descend to the immediate motive cause and the Mechanic mode of their operating from what we have already said it is manifest that it is as impossible for the heart to be inflated and moved by an incorporeal Faculty or by Spirits or by the bloud alone however violently rushing into it or by the same bloud to what degree soever rarified in its Ventricles or by a Fermentation conflict and displosion of Acid and Saline juices met together in the heart as it is for the Muscles of the Limbs to be regularly moved by the same causes It remains therefore that as all other Muscles are moved by contraction of their Fibres the Pores of them being filled and distended so also it is most probable that the proxime or immediate cause of the motion I mean only the Constriction of the Heart is the dilatation or distension of the Pores of its Fibres which causes their abbreviation or contraction i. e. the Systole of the heart But what the Mediate Cause is by which the Pores of the Fibres are dilated to the abbreviation of the Fibres themselves we shall after a few minutes enquire In the mean time I will lay down this other PROPOSITION That the Mediate Cause of the Hearts Motion seems to differ from that by which the Muscles of the Limbs are incited to Voluntary Motion Since it is a truth known to all men that we can move what Muscles we please of any Limb and continue their Motion as long as we please and stop it when we please but the Motion of the Heart is not subject to the Empire of our Will but like that of a Mill perpetual whether we sleep or wake and since even without our knowledge or perception the heart as agitated by a certain natural necessity makes most vehement and almost momentany strokes or jerks alternately short and Isochronical or equally temporaneous pauses interposed betwixt them nor ever either much varies that constant Rhythm of its pulse while we are in the state of health or intermits the same during life therefore certainly there must be somewhat of difference between the mediate cause of the hearts natural motion on one part and the mediate cause of the voluntary motion of all other Muscles on the other Besides in an Egg from the first days incubation of the hen the punctum Saliens and then the Vesicula pulsans exhibite to our sight this dance of life already begun when we cannot conceive it to be possible that there should be in that first rudiment of the foetus any sensation of good or evil any will to pursue the good or avoid the evil and when nothing of the brain is yet formed Nay more in the heart of a Viper taken out of the body and put into warm water the Pulsation is observed to continue many hours when by reason of the abscission of the Nerves all commerce betwixt the Brain and the Heart being extinct no sensation or election can be imagined to ordain and command that motion Wherefore we are obliged to confess that the first and mediate cause of the hearts Pulsation is in some respect or other divers from that whereby the other Muscles are incited to motion at the command of the Will But to explore wherein this nice difference may most probably consist is a work of so great difficulty that I wish it were possible for me to revoke the temerarious promise I made to attempt it nor should I have courage enough to carry me so much as one step farther if I did not derive it wholly from the well known Candor and benignity of my most Learned Auditors For the remaining part of my way though short is yet dark and rocky with Precipices on both sides and all the light I can expect must be from a few Sparks stricken out of my Flinty subject by the force of conjecture If therefore I chance to stumble or err humanity will oblige you rather to put forth your hands to support or guide me than to deride my blindness In hope of this favour I will venture to procede Certain it is that the first and mediate Cause of the Motion of the Heart as well as that of the motion of the other Muscles whatsoever it shall at length be found to be is derived to it by the Nerves from the Brain For as if the Nerve inserted into any Muscle be strictly compressed by a Ligature or cut off the power of motion in that Muscle is presently intercepted or totally destroy'd as common experience witnesseth So if the Nerves of the Eighth conjugation be either strictly compress'd by a Ligature round about or cut off in the neck of any Animal there suddenly will ensue a visible change in the Motion of his Heart witness the memorable experiment made by Dr. Lower and recorded in his excellent Book de Corde where he affirms that the heart which before reciprocated its Motions moderately and Rhythmically presently after the Ligature had been made upon the said Nerves began to palpitate and tremble and by degrees grew more and more languid till the poor creature died which was within two days Other experiments confirming the same thing I might alledge if it were not universally acknowledged by Anatomists that the Motive force of the heart depends upon some influence from the Brain And among these one of the most accurate affirms that Nature made the Cerebellum as a Storehouse of Animal Spirits chiefly for the use of the Heart that the Motion of it might be perpetually maintained saying Pro motu Cordis praestando tam sedula sollicita fuit naetura ut praeter Nervorum propagines ubique in illud densè distributas pro continuo spirituum animalium influxu Cerebellum insuper quasi perenne corum promptuarium ei accommodaverit A cujus benigna constante influentia adeò dependet ut fi spirituum influxus vel minimo temporis momento impediatur motus ejus illicò deficiat But why have I recourse to the authority of men when Nature herself in her constant process of forming the parts of an Embryon seems to
little Canales within must therefore be full of small asperities it is necessary that the Succus Nervosus whose consistence is not much thinner than the white of an Egg well beaten should pass through them with a slow and interrupted course and at length fall out of their lower ends in drops with equal pauses between the drops Where we find a parility of Causes we may rightly expect a similitude of effects Here I see two formidable Difficulties standing like Romantick Giants in my way to deterr me from proceeding and I cannot without shame and infamy decline to encounter them One is That after the Cardiac Nerves are cut off and the heart itself taken out of the body the Pulsation of it continues for some time To remove this therefore I say that the cavities of the Nerves annext to the heart may remain still full of and turgid with the roscid Succus Nervosus which being hindred from regress by their spontaneous contraction toward the heart and kept in a state of fluxility by the yet lasting warmth of the heart may for some time be instilled into the Fibres of it and by swelling of them cause them to constringe the Ventricles as before Then the heart being irritated by the prick of a needle or some sharp and pungent liquor may be able by its peristaltic constriction to squeez out the few remaining drops of the roscid liquor Which being done the Pulsation ceaseth for ever To the bloud this effect ought not to be ascribed for after all reliques of it have been with warm water and a Syringe washed out of the Ventricles and squeez'd out of the Vessels the Pulsation notwithstanding will continue for sometime Nor can it be with more reason ascribed to Convulsions of the heart because all convulsions are disorderly and unequal both in the times of their girds and in those of their intermissions whereas in this case the Pulsations are regular and isochronical with equal pauses Nor to the Heat communicated by the bloud to the heart before it was exsected and not yet quite extinct because that borrowed heat soon vanishes and no external heat will revive the languishing Pulsation after all the roscid juice hath been exprest out of the ends of the Nerves left in the heart Nothing then remains to solve this Phaenomenon but the instillation of a few drops of our roscid liquor into the Fibres of the heart to swell them and so urge them to constriction of the Ventricles The other Difficulty is this Why is there not a Pulsation after the same manner also in all the Muscles of the Limbs since their Fibres are of the same nature in all things their disposition and direction only excepted since the Orifices of the Nerves perteining to them are in the Brain as open to admit and imbibe the Succus Nervosus there elaborate and provided for them and since the same Nerves are equally spongy and permeable in their constitution and so apt to transfer that liquor as the Orifices of the Cardiac Nerves are to receive or their Canales to transfer it If the whole apparatus be the same on both parts whence comes it that the same effect is not produced in both At this Goliah I have in my Scrip three Pebbles to throw and though my arm be weak I will not despair of hitting him in the forehead First therefore I say that it is not yet certainly known to any mortal man by what mediate cause the Muscles of the Limbs are moved at the command of the Will whether by simple contraction of the Originals of the Nerves inserted into them or by the immission of the Succus Nervosus more copiosely and swiftly at the time of their being put into action though the Mechanism of their Fibres make it more probable that they are moved by immission of some liquor from the Brain by which the rhomboid meshes or pores of their Fibres being all at the same time swell'd and dilated a contraction of the whole Muscle must in the same moment be effected and therefore I prefer this opinion to the former and have followed it in many places of this rude Discourse But yet this opinion hath not led me to a discovery of the Cause of the difference this present difficulty compells me to hunt after Should I imagine Valves affixt by Nature to the Orifices of the Nerves of the Muscles as Mons Des Cartes did in the bodies of them though such an artifice be not impossible yet beside that no such Valves have hitherto been found in the Brain I should still be to seek for a Cause to open and shut them ad arbitrium voluntatis and so should be put to a stand in my disquisition Which to avoid some other Organical contrivement such as may be not only possible but probable also and facile and fit to untie this Gordian knot must be excogitated Let it then be supposed that in the Brain the Orifices of the Nerves thence elonged to the Muscles of the Limbs and their Canales are in such a peculiar manner formed as at no time to take in and convey into the Muscles more of the roscid liquor than what is sufficient to nourish them and recruit their vigor unless when at the command of the Will under whose jurisdiction they properly are the Nerves being twitched up or convelled at their Originals both their Orifices are dilated to receive and their Canales rendred more pervious to transmit in a moment into the Fibres of the Muscles to be used a greater portion of the same invigorating liquor viz. so much as is requisite to swell them up by replenishing their pores and force them to contraction which is the common action of all Muscles On the other part let it be supposed that in the Brain Nature hath framed the Originals of the Cardiac Nerves by a different Artifice namely such as that not only their Orifices may always be open to imbibe but also their Canales so easily pervious to transmit the roscid liquor as that without any Vellication without any Convulsive motion the same liquor may merely by the plenitude of the Canales themselves be effused guttulatim into the Fibres of the heart to cause the alternate constriction or Pulsation of it And it is the more lawful for me to suppose this difference of structure in Nerves ordained for different uses because it is above all doubt that the Optick Nerves have a peculiar fabric and contexture wherein they differ from the Auditory and all other Nerves inservient to the rest of the external senses and that the Organ of every sense hath its nerve of a peculiar constitution accommodate to the nature of its proper object though those differences consist in such minute and subtle artifices as have hitherto eluded our most curiose researches though assisted by the best sort of Microscopes Why then may it not be thought that Nature hath given to the Cardiac Nerves also a constitution divers from that of all
the consequent abbreviation of a Cable to be of so great efficacy that the violence of a Tempest the weight and jerks of a loaden ship of 1000 Tuns burden and the current of the Sea cannot by their united forces extend the Cable to its former length This ye will confess to be admirable that a little water insinuating itself into the Pores of the threds of which the Cable is composed should dilate those little and indiscernible Pores with such prodigious force as not only to swell the close and hard twisted Cable but to countervail nay exceed the aggregate of the forces of a furious wind a strong current of the Sea and the weight of so great a Ship with its whole Fraight Yet common experience testifies this to be true The Second Example will perhaps raise your admiration to a higher degree being of all of this kind that hitherto I have ever read or heard of the most memorable It is this In Rome there stands at this day an Obelisk of one solid stone a kind of Ophite or spotted Marble anciently consecrated to the honour of the great Iulius Caesar and erected in the Cirque of Nero but in the Year of Our Lord 1586. removed into a more eminent place at the vast charge of Pope Sixtus Quintus and by the admirable skill of Dominicus Fontanus an excellent Architect and Engineer This stone is in height 170 feet above the base in breadth at the bottom 12 feet and at the top 8 in weight 9586148 pounds and the weight of the Cables Chords Pullies and other moveable instruments used in raising it amounted to 1042824 pounds according to the computation of Georgius Draudius The removing and erection of this Obelisk was thought to be so rare a work of Art that the Engineer beside the great mass of treasure he received for a reward from his Holiness thereby acquired to himself immortal renown no less than 56 Learned men having since profestly written to describe his Machines then used and to celebrate his praises as Monantholius relates But all their praises notwithstanding he owed no small part of his honour to Fortune or rather to a Carter that stood by an idle Spectator For the Engineer a little mistaken in his forecast of the stretching of the Cables and Ropes found when he came to set the erected Obelisk upon the Pedestal that he had not raised it high enough by 2 or 3 inches and to raise it higher with those Machines so stretcht was impossible Confounded with shame and despair by this unforeseen faileur he begun to meditate flight to save his life which he had pawn'd to the Pope to be forfeited if he did not accomplish the difficult work he had undertaken when as good luck would have it out of the croud of vulgar gazers comes a Carter and advises him to cause all his Cables and Ropes to be wet with water Which done the Ropes quickly swell'd and shortned themselves so that they lifted up the Column to a due height and then the overjoy'd Fontanus with ease placed it upon the Pedestal Now if ye shall be pleased to reflect upon this Example and to consider that a little water only by dilating the Pores of the threds of the Cables and Ropes swell'd and shortned them with force great enough to overcome the immense gravity both of the Obelisk and of themselves with the rest of the Mechanic apparatus then used which gravity hath been computed to your hands I am confident you will no longer think it impossible for a few little drops of liquor diffused through the Fibres of the Heart and like wedges dilating their little Meshes or Pores so to swell and abbreviate them as to cause a constriction of the Ventricles and that too with a force if Borellus his estimate be right exceeding the force of 3000 pounds weight And as for the Probability of this proposition that cannot be obscure to any man of common sense who shall consider first the near similitude that is between the threds of a chord and the Fibres of the heart in Figure in tenacity and strength in aptness to swell and consequently to shorten themselves upon humectation and in the faculty of restoring themselves to their natural tone after extension and then the little or no difference betwixt water and the Sucâ—us Nervosus as to the power of insinuating into and dilating the Pores of bodies naturally apt to swell and shrink For since the two Agents viz. water and the Succus Nervosus are so alike in their efficacy as to the dilatation of the Pores of Tensile bodies and since the two Patients also viz. the threds of a chord and the Fibres of the heart have so full a resemblance in their nature it is highly probable if not necessary that like effects should be produced by them And this probability is the greater because of all other Efficient Causes hitherto excogitated by Learned men to solve the grand Phaenomenon of the Pulsation of the Heart none can be given which is either so intelligible or so congruous to the whole Mechanism of the Heart as this which I have in this Lecture endeavour'd to assert But this Chair doth not make me a Judge To hear and determine Most Excellent President and my most Learned Collegues is your right which I ought not to usurp I will therefore first to ease your memory reduce into few words the heads of what I have deliver'd concerning the Efficient Causes of the Motion of the Heart and then humbly and without reserve submit all parts of my Disquisition for I pretend not to know but only to inquire truth to your examen and judgment The summ of the Precedent Hypothesis is this I suppose First That the immediate Efficient of the Pulsation or Constriction of the Heart is the abbreviation of the Fibres of it arising from the dilatation or expansion of their Pores or little meshes Secondly That the Mediate Efficient is the Succus Nervosus derived from the Brain through the Cardiac Nerves which being instilled into and diffused through the Fibres of the heart fills and dilates their Pores and by necessary consequence abbreviates them with force sufficient to make the Systole or constriction of the Ventricles and to express the bloud contein'd in them Thirdly That the short quiets or pauses interceding betwixt the Systoles of the heart arise from equal pauses or intermissions betwixt the drops of the Succus Nervosus instilled into and swelling the Fibres of the Heart and that as the times of the droppings are equal among themselves so are also the Systoles of the Heart isochronic or aequitemporaneous Fourthly That the motion and guttulation of the Succus Nervosus into the Fibres of the Heart being accelerated or retarded by whatsoever causes the Systoles of the Heart must be more or less frequent proportionately thereto Which things if ye now at length shall judge to be consentaneous to right reason agreeable to the Animal Oeconomy
congruous to the Organical structure of the Heart to all which I have been careful to adjust them and in fine consistent among themselves then I shall with assurance conclude that the Heart is as all Automata are moved by Mechanic necessity Which is what I proposed to demonstrate even without that incredible displosion of Saline and Acid spirits in the Heart first imagined by Doctor Willis and since asserted by a man of much greater Erudition and more solid judgment namely Alphonsus Borellus as necessary to be supposed in order to the Solution of this great Probleme of the Pulsation of the Heart and that of the motion of the rest of the Muscles Which pretty conceit I will first revive in your memory by reciting a few of Borellus's own words faithfully and then offer to your consideration the reasons that have induced me to reject it Restat igitur saith he quòd sicut omnes musculi contrahuntur inflatis vesiculis eorum pororum sic quoque immediata causa tensionis Cordis erit inflatio vesicularum pororum ejus facta à fermentativa ebullitione tartarearum partium sanguinis à succo spirituoso ex orificiis nervorum instillato c. The Reasons that disswade me from assenting to so great a man in this matter are these First We have the testimony even of our sight the most certain of all our senses that in an Egg after a day or two's incubation of the Hen the Punctum saliens first and then the Vesicula pulsans are agitated by a manifest Pulsation in the Centre of the Colliquamentum or genital humour which is a pure and homogeneous liquor even before any the least sign of bloud can be discerned Here therefore the supposed immediate cause of the Hearts motion viz. an inflation from a Fermentative ebullition of the Tartarous parts of the bloud meeting and conflicting with the spirituose juice instilled out of the Nerves into the Heart certainly can have no place For at that time in the Egg neither Heart nor Brain nor Nerves are yet formed nor is any part of the Colliquamentum converted into bloud causarum in rerum natura nondum existentium nulli dantur effectus Beside the same Vesicula pulsans is from the beginning of the change of the genital liquor into bloud not only the Conceptacle of it but also the Engine that gives it motion and therefore the new made bloud can contribute nothing toward the Pulsation thereof Secondly If not only the natural motion of the Heart but also the Voluntary motion of the rest of the Muscles procede from an explosion of mutually hostile spirits concurring and combating in them as Borellus affirms why have not all other Muscles as well as the heart a perpetual Pulsation in them when the same bloud and the same Succus Spirituosus perpetually concur in them no less than in the heart And what dominion could the Soul have over the Muscles of the Limbs to exercise which of them she pleases and as long as she pleases and give them rest when she pleases if they were agitated every moment by Squibbs or Crackers breaking within them certainly she could never moderate such violent and tumultuose explosions Besides it is wonderful strange if those explosions be made in a Muscle when it acts that we should never perceive it to be distended or heaved up outwardly but that on the contrary we should plainly perceive the Muscles in all voluntary motion to be strongly constringed inwardly to be minorated and become harder which is a certain indicium that they are moved in a manner quite contrary to inflation Thirdly Such an explosion made in the heart might indeed cause the Diastole of it by inflating and distending the Ventricles but would hinder the Systole or constriction of them inwardly which is requisite to the expression of the bloud For the supposed explosion consisting like that of aurum fulminans or Gun-powder in a motion expansive would of necessity dilate the cavities of the heart Fourthly If an explosion of Acid and Saline liquors meeting commixt and warring in the heart be the immediate efficient of its motion it is consentaneous to infer that where the ingredients of this explosive mixture are more copiose there the explosions ought to be more frequent è contra But in sucking infants who being nourished only with milk cannot reasonably be thought to have much if any thing of Acidity in the nutritive juice or of saltness in their bloud the Pulse of the heart is notwithstanding even in the state of health at least doubly quicker or more frequent than in full grown men nay such who delight to feed on salt meats and drink plentifully French and other subacid Wines Ergo 't is highly improbable that the Pulse of the heart should be the effect of such explosion These are the reasons that moved me when I came to this instable bogg to withdraw my judgment from the conduct of Borellus whom before I had so closely followed and to divert into a private way which seem'd to promise me smoother and firmer sooting and which notwithstanding I will not commend to others unless your approbation shall encourage me to pave it Meanwhile the hour-glass admonishing me to reserve till I meet with some other opportunity what may be farther alledged to confirm the precedent explication of the Efficient Causes of the Systole of the Heart I will now add no more than three short Advertisements and resign you up to the more profitable and more pleasant entertainment of your own better thoughts The First is that is probable that in every Diastole of the heart the few and little drops of the Succus Nervosus which by wedging themselves into the small Rhomboid Pores or meshes of the Fibres of the Heart and so dilating them caused the immediately precedent Systole are by the restitutive motion of the same Fibres squeez'd out of those Pores into the Parenchyma of the Heart whence they are absorbed and carried off with the bloud by the Veins and so make room for the next succeeding drops to cause the next Systole and so the Systoles and Diastoles of the heart come to be alternately repeted and the Circulation of the bloud to be perpetuated This I say is probable because Nature hath instituted the like absorption of the redundant Succus Nervosus by Veins in many other parts of the body more eminently in the upper part of the neck where the Iugular Veins imbibe whatever humour distills from the bottom of the Brain as Doctor Lower expressly affirms and with good reason in these words Humor omnis è cerebro proveniens in venas jugulares resorbetur I had heretofore I confess a thought that the humour contein'd in the Pericardium might have no other fountain but the reliques of the Succus Nervosus expressed out of the Fibres of the Heart in the Diastoles when after violent Tension they exercise their natural faculty of restitution But when I had
seen that the liquor found in the Pericardium is easily capable of coagulation either by heat or cold so as to become like gelly of harts-horn or the white of an Egg hardned by boyling as the Serum of the bloud will do and observed the various little Glands seated about the Basis of the Heart for which I could find no other equally probable use as to instil the Serum into the Pericardium to facilitate the motion of the heart which most certainly that liquor doth as the humor instilled out of the glandulae lacrymales upon the outsides of the eyes serves to moisten and make them more easily moveable every way when I had I say observed and considered these things I rejected that thought and embraced this of the absorption of the reliques of the Succus Nervosus by the Veins of the heart The Second is that the Diastole of the Heart is caused partly by the Relaxation of the Fibres of it spontaneously restoring themselves to their natural posture and length as all other Tensile bodies are wont to do after they have been distended partly by the force of the bloud rushing out of the Ears into the Ventricles of the Heart and replenishing them Wherefore the Wisdom of Nature is admirable also in this that she ordained these Two Causes of the diastole viz. the relaxation of the Fibres and the influx of the bloud into the Ventricles to be exactly coincident that with united forces they might cooperate more efficaciously Whence it appears that in the diastole the Heart is not wholly Passive as all Anatomists hitherto have believed it to be For unless the Fibres did restore themselves to their former longitude which is a natural action at the same time the influx of the bloud happens certainly there could be no room to receive the bloud because the insides of the Ventricles would continue to touch each the other and so there could be no diastole The Third and last is that it appears from the whole Series of this discourse that the Pulsation or Constriction of the Heart hath its force from that Mechanic power which is called the Wedge and that the bloud is expressed out of the Heart by virtue of another Mechanic power which is named the Praelum or Press and consequently that the Heart itself is as all Automata are moved not by Spirits nor by a Pulsifick faculty nor by rarefaction of the bloud nor Ebullition or Fermentation of the bloud nor by explosion of Saline and Acid spirituose liquors but by Mechanick necessity Which from the beginning I hoped I should be able fairly to prove If the success of my endeavours hath not been answerable to that hope I will not go about to extenuate the blame of my faileur by citing examples of much greater Wits which have before me in vain attempted to reveal the same secret of Nature but consolate my self with this that my Iudges are men no less beloved for their exemplary candor and humanity than honoured for their excellency in all kind of Learning and who need not be put in mind That Truth is a tree whose root is in Heaven and of which even the wisest of us dim-sighted Mortals here upon earth see nothing but the shadow of its branches I will therefore conclude this inelaborate Disquisition with that memorable saying of the Prince of Roman Orators De his statuat unusquisque ut libet Quid autem verius sit Deus ipse viderit hominem quidem scire arbitror neminem ¶ ⸫ MY Lectures such as they are much Honour'd Auditors Ye have with obliging patience heard Be pleas'd I beseech ye to hear also before ye rise a word which I have to speak in my own defence Were it not indecent to compare small things with great I should venture perhaps to advertise you that the reasons which induced me to attempt a reformation of the Borellian Hypothesis of the Motion of the Heart which Doctor Harvey himself call'd the Sun of the Microcosm seem to have some kind of Analogy to those which moved the Prince of Astronomers Tycho Brahe to dislike the Ptolemaic System of the Macrocosm or greater World and to excogitate a new one of more probability and neatness For as Tycho animadverting that the Celestial Orbs had been by Ptolemy distributed unhansomly that so many and so great Epicycles were in vain imagined to explicate the retrogradations of the Planets and their various respects to the Sun and that the equality of the Circular motion was measured not from the Centre of its proper Circle as it ought but from the Centre of another Eccentric Circle against the first principles of Nature and Art invented a new System exempt from all these incommodities which is in truth the Copernican inverted So I conceiving that in the Borellian Hypothesis and Explosion of I know not what Saline and Acid materials in the Heart was not only in itself extremely improbable and incongruous to the Wisdom of Nature which always constitutes certain and regular Causes to produce certain and regular Effects but also unnecessarily supposed to solve the Phaenomenon of the Hearts Pulsation set my dull Brain on work to reform it and soon invented another that seems both free from those inconveniences and more agreeable to the Organical Structure of the Heart to which above all things it was requisite I should endeavour to adjust it This I thought my self obliged to signifie lest any here should believe either that I have usurped to my self this whole System of the Motion of the Heart from that most excellent Mathematician Alphonsus Borellus whose Memory I highly honour or that I lay claim to more than a Candid attempt to reform it ¶ ⸫ EPILOGUS PRAELECTIONVM quidem vela jam tandem contraxi nondum tamen dissolutam video concionem Resistamus igitur hîc parumper Auditores Ornatissim◠si vobis ita videatur ad stupendam illam cujus rationem Mechanicam hactenus tam anxiè inquisivimus Cordis fabricam seriò respiciamus Inde enim etiamsi alia omnia in universitate rerum deessent Divinae Architecturae documenta cuivis hominum pronum est inferre quà m sit immensa illius caeterorumque omnium in hoc Mundo adspect abilium CONDITORIS solertia quámque parum ab immedicabili cùm animi tum mentis stupiditate olim abfuerit Epicurus Qui Animalia casu quodam in prima rerum procreatione genita fuisse vecorditer censuit opinatus est consequenter totam in iis membrorum varietatem dearticulationemque non aliunde quà m ex Atomorum fortè fortuna post infinitos inter se in spatio infinito vortices ita concurrentium atque commistarum dispositione extitisse Quamobrem neque ullam fuisse intelligentis Naturae prudentiam quae ossa cerebrum cor nervos venas quae oculos manus pedes viscera quae caetera omnia conformans ad fines certos seu functiones partibus congruas respexerit sed singulas partes ita