open so as to convey a sufficient quantity of Spirits the Motion is continual and without Intermission The Reason of the Difference will easily appear if we do but take Notice how when a Vein is opened the Blood runs out continually without ceasing or intermission but if an Artery be opened it gushes out with Intermissions answerable to the Diastoles of the Heart because the Veins are always as a common Cistern distended with Blood and before they can be emptied with a small Orifice they are filled by the Extremities but the Blood being continually received by the Extremities of the Veins and those Extremities being furnished with Valves to hinder it from Regurgitation the Arteries are always kept more lank and empty and are not as the Veins distended with Superfluous Blood So that it only flows out of them when they are distended upon violent Systoles of the Heart In like manner that part of the Brain that furnishes the Nerves serving to Voluntary Motion with Spirits is like a common Cistern full of Spirits and when Vent is given the Pores being opened according to our Appetite the Spirits are thrust forth in one constant course But the Muscles serving to Involuntary Motion being in continual Action do so drain their Store-house as to keep it more flaccid and empty so that the Animal Spirits as they are prepared are continually waved through their proper Pores and as one Wave follows another so one Contraction perpetually succeeds the Subtile Liquor being according to the same Rules prepared in the Glands and thrust out through the Fibers Some of the Muscles designed for Involuntary Motion are in some measure subject to our Will so that it lies in our power to retardate or quicken the succession of their Contractions but not totally to obstruct or hinder them as the Muscles serving to Respiration The Reason of which is this The Pores of the Brain leading to the Nerves which convey Spirits to these Muscles are so framed that they carry Spirits to them as to the other Muscles serving to Involuntary Motion in a competent Quantity but these Pores differ from those for as much as these have such an Organick Motion as to contract or dilate according to our Appetite we can by a constriction close up these so as to deny a Passage for Animal Spirits sufficient to prepare a quantity of the Subtile Liquor to cause due Contractions of the Muscles till by degrees they increase to such a great Quantity and distend their Receptacles so long that those are no longer capable of receiving more till that force which drives them violently into the Receptacles overcomes the constrictive Faculty of the Pores and then the Spirits against our Will break forth and flow violently into the Musculous Glands It is easily noted that after we have holden our Breath a long time the first Contractions are as if Two or Three were joyned together without intermission I mean so long continued which is sufficient to prove what I have said of the Muscles serving to Respiration For when by a Constriction of the Pores the Spirits which ought to flow out are kept in and heaped up in their Receptacle and Two or Three Contractions are by that means hindered that Receptacle becomes like a common Cistern and as soon as the Pores are forced open the Spirits running out cause long continued Contractions till that store is spent and then they wave through as before the Interruption What I have hitherto said might be sufficient to prove my Hypothesis reasonable but to illustrate it a little more I shall explain some of the Phaenomena about Muscular Motion and give sufficient Reasons for them agreeable to my Hypothesis Common Experience tells us that Old People whose Spirits are flat and weak are most usually subject to a Trembling of their Head or Hands the Reason of which is this The Fermentation in the Glandules is too low and weak and doth not subtilize a sufficient Quantity of the said Liquor to keep the Muscles in a constant Motion The Reason why a sufficient Quantity of Liquor is not prepared is plain for though their Appetite and Desire is strong enough and endeavours to open and dilate the Pores of the Brain yet when the Spirits are weak it 's a sign few are separated from the Blood and if few be separated they cannot flow plentifully into the Nerves be the Pores never so wide This confirms the Reason I have given why the Systole of the Heart is interrupted with constant Diastoles For the Store-house which supplies it is always kept empty by reason of the constant efflux of Spirits and in Old People the Store-house which furnishes the Nerves serving to Voluntary Motion with Spirits is kept empty because few Spirits are separated from the Blood and as they are separated they are continually spent by a constant distribution of them to prepare Nourishment in the Musculous Glands So that when the Pores are opened wider for Voluntary Motion for want of a sufficient Stock they cannot flow out in a constant and equal proportion but as they are separated they wave through those Pores that are most ready to receive them The Motion indeed is not interrupted with such perfect Intermissions because this Store-house is not so clearly drein'd but there is a perfect Remission because the Stock is not so copious as in Young and Lusty People to yield constant Supplies Moreover when the Spirits are weak it s a sign that the Blood is much depauperated and declines from its Natural state and then there is more need for strong Spirits to raise the Fermentation in the Glands and to subtilize the Liquor Upon which account when the Spirits are weak the Disadvantage must needs be the greater Hence may be deduced a Reason why when our Spirits are low and almost spent though our Appetite be strong we cannot perform strong Actions From hence it may be proved that there is something prepared in these Glands by the Animal Spirits which is incapable of entring into the Fibers till prepared For whether the Spirits be weak or strong there is a sufficient quantity of Arterial juice laid down in the Glands tho' it s not made capable of passing into the Fibers but as it is prepared accordingly as the Spirits are more or less in quantity stronger or weaker I have known Women who seemed healthful and of a Sanguine Complexion whose Hands wou'd when they were about any Moderate Exercise Tremble as if Paralytick For the Mass of Blood being a little more than usually depraved and degenerated from its Balsamick and Sulphureous into a more crude and Phlegmatick State was unapt for Fermentation so that the Animal Spirits being not able easily to prepare a sufficient quantity of the aforesaid Subtile Liquor to keep the Muscle in a constant Motion were forced to do it by an unequal Influx just as an Horse set to draw too great a Burthen is forced by many reiterated draughts
the Blood is a Pondus by which the action of a Muscle is performed The grounds of this suspition are cheifly taken from two Experiments The first is a Ligature on the descending ttunk of the Aorta whereby all the inferior Parts became destitute of Motion which they recovered again when that Ligature was loosed The second is to be taken for a more surprizing Argument because after a cessation of Motion the Muscles of the Legs renued their Contractions by an Injection of Water into the Crural Arterie But that there is no Reason to assert that the Blood acts as a Pondus from these Experiments will hereafter sufficiently appear by giving other Reasons for these Phenomena In the mean time to evince that the Blood as a Pondus does in no wise help the Contraction of a Muscle but does on the contrary much interrupt and resist the Intumescence of the Musculous Fibers by which the Contraction of a Muscle is performed let any one hold his hands before a Fire with his Arms perpendicular continuing 'em in that posture till he feels the Musculous Parts well filled with Blood then lifting up both his Hands let him hold 'em up as high as he can till the Pondus of the Blood be drained and the Veins which before were full and tumid become flaccid and empty and he 'l move his Fingers much more easily and swifter when the Muscles are eased of the Pondus of Blood than he did whilst his Hands were dependent yet certainly there was a greater Pondus of Blood upon the Muscles in the former posture whilst they were tumid than in the latter when emptied of superfluous blood Another Argument to prove That the Pondus of the Blood doth not at all promote the Contraction of a Muscle may be taken from the Observation of Cacochymick Bodies who are far more dull and unapt for Motion than healthful people whose Veins and Arteries are moderately filled with Blood which is not so thick and heavy for in Cacochymick Bodies there is a greater Pondus of Blood but because it doth not yeild matter for to swell the Carnous Fibers as plentifully as blood of a more healthful constitution Motion is not so brisk and strong whereas if the Pondus of the Blood did any ways contribute to the performance of Muscular Motion they would be far more strong for the thicker the Blood is the greater is the Pondus In the Muscles of the Legs and Thighs there is always when the Body is erect a greater weight of Blood than on the Muscles belonging to the Hands and Arms and yet the latter are far more agile and nimble in Motion Again if we but make a Ligature two or three fingers breadth above the Cubit so as to hinder the Reflux but not the Influx of the Blood when the Sanguiferous Vessels are swelled and the Muscles well filled they are rendered much more unapt for Motion Which evidently shews that the more the Sanguiferous Vessels are distended the more the Motion of a Muscle is hindered because when the Vessels are dilated they resist the Intumescence of the Carnous Fibers and consequently the Contraction of a Muscle Furthermore That the Contraction of a Muscle is not perform'd by the Pondus of the Blood is apparently evident in the following Experiment Viz. Make a Ligature two or three fingers breadth above the Cubit so strong as to stop the Circulation of the Blood then open the largest Vein with the common Instrument and the Blood which more than usually swelled up the Sanguiferous Vessels will leap forth but presently for want of subsequent Matter and due Circulation the Vein falls and the Blood ceases to run yet by a Contraction of the Muscles to which that Vein leads forthwith part of the Blood which lay in the Muscle is forced out which plainly shews there is less Blood in a contracted Muscle than before Contraction The same appears also in Runing or any other violent Exercise in which most of the Muscles are Contracted for presently the Blood flows more than usually upon the tender Lungs and causes an Intollerable shortness of Breath Because by an Intumescence of the fleshy Fibers the Muscles are not only made incapable of receiving so much Arterial Blood as before Contraction but also because the Blood which lay in the Veinous Ducts is driven out more forcibly upon the Heart and the Heart being overwhelmed drives it out upon the Lungs Whence proceeds that Palpiration of the Heart upon violent Motion not directly as Dr. Croone supposeth because an Instinct is sent from the Brain to raise stronger Pulsations that the Blood may forcibly be driven into the Muscles and thereby cause Contractions for then why doth it not at the first instinct thus oppress the Lungs with its quantaty but this strong Palpitation is Accidental for when the Blood is more than usually driven upon the Heart and not so plentifully received by the Muscles by degrees it oppresses the Heart with it's quantity and the Animal powers being sensible of the oppression raise stronger Systoles to drive it out which presently is received and heaped up in the Lungs as a Part less able to resist its violent Incursion Nay many times when the Vessels are well filled with Blood by violent and frequent Exagitations betwixt the Contraction of the Heart and of the Muscles its texture is so loosened that it ferments and boyles up so that the Lungs are not only swelled up and almost stifled being rendered uncapable of receiving Air but it is also more strongly forcibly driven into the Muscles themselves and there distending the Sanguiferous Vessels hinders the Intumescence of the Fibers and thereby the Contractions of the Muscles So that I have not once trying this Experiment found such an Oppression on my whole Thorax and such contrary and in some measure painful endeavours betwixt the Sanguiferous Vessels tumified and the Carnous Fibers striving to swell that I was forced to lay me down to the end that the Carnous Fibers being flaccid might give way to the incourse of the Blood and by receiving it more plentifully might case both my Thorax of its Oppressions and that the Carnous Fibers yeilding to the Sanguiferous Vessels might put an end to that uneasie contention Thus much I think is sufficient to prove that the Blood as a Pondus hinders the Contraction of a Muscle Dr. Ridley supposes That the Nervous and Carnous Fibers are only a Congeries of Fluids contained in certain Vessels and that by Reason of a Plenitude in the aforesaid Vessels the whole Machine is in a constant AEquilibrium so that it will follow upon the common Postulatum viz. That the Sensitive or Rational Soul can command the Animal Spirits into a primus impetus and that part of that Liquor whenever a Muscle is Contracted is transmitted through the Vessels from the Brain to its Carnous Fibers and causes the Intumescence of a Muscle the same Liquor at
each Muscle which according to Anatomists are Four Nerves Arteries Veins and Lymphaeducts the Nerves and Arteries furnish the Muscles with Spirits and Blood the Veins and Lymphaeducts carry back the superfluity of Blood and Lympha The Branches of all these Vessels are minutely distributed through the whole Muscle and by an intermixture and texture of the most Minute and Subtile Branches of the same is formed that Substance which fills up the Interstices of the Fibers and which denominates the whole Belly of a Muscle Fleshy The colour of these Vessels as of all others is without doubt White but by the Contents of the Sanguiferous Vessels the whole Belly of a Muscle is coloured Red. The Terminations of these Vessels are so minute and small so brittle and subject to be broke that it 's as difficult to trace and find their Terminations and Insertions as to divide a Hair into an Hundred Parts and though many things are made visible by the help of Microscopes which are otherwise too subtile to be discerned and discovered by the naked Eye yet I am not without Reason perswaded that the terminations of these Vessels cannot be perceived by the help of a Microscope Some indeed whatever they think is probable lest it should not be credited presently strenuously affirm they saw it with their Microscopes and so easily impose on those that less inquire after truth themselves but take it on trust from others and perhaps prevent those not so exquisitely skill'd in Microscopes from making any further search after truth I shall not here say that what I propose concerning the Terminations of these Vessels was seen with any Microscope but shall declare my Opinion in this Matter too subtile for any Microscope but Reason It being impossible for any one to understand the true Reason of Muscular Motion unless first acquainted with the distribution of these Vessels and their Contents first I conceive that as the Nerves Arteries and Veins are all distributed through a Muscle so it is but Reasonable to conclude that their minute and subtile twigs are all before they terminate interwoven and mixed with one another And if so it will not be absurd to imagine that they all end as it were in small and Diminutive Glands And if the ends of the Vessels be so small that their terminations cannot be perceived by a Microscope these Glandules composed of the Invisible ends of the aforesaid Vessels must needs be very small and fine and consequently may not be perceived by the help of extraordinary Microscopes From these Glandules thus formed are derived short Ducts or Passages for the conveyance of a subtile Liquor out of the aforesaid Glandules into the Cavities of the Carnous Fibers This Passage very likely may be composed of the external Arterial Coat Into the Cavity of the Carnous Fibers besides these Ducts the twigs of the Lymphaeducts are also inserted to carry back a superfluous Lympha If any one thinks it improper or absurd to assert that these Vessels do thus terminate as if it were in small Glandules let him but consider what a Gland is and how it is composed and he will not think the Conclusion irrational For a Gland is nothing else but a Composition of an Infinite Number of small and diminutive Vessels several and most of which have Communication one with another which Gland so composed is as a Store-house to receive and contain a certain Liquor till necessity requires or its quantity causes an exclusion of it And this seems plainly to be favour'd by Dr. Ridley when he says that the whole Body is a continuity of Vessels ad infinitum Now if a Gland consists of an infinite Number of small Vessels and if the Branches of Nerves Veins and Arteries be divided before they terminate into an innumerable number of most invisible twigs as is most certain when from one twig of each sort is derived a vast number and all these so derived are mixed and interwoven one with another why may we not say at least Metaphorically since they in their Distributions imitate the Composition of Glands that they terminate in small Glandules Some perhaps will ask how must we discover these Glands Malpigius hath observed the Liver to be composed of Clusters of Glands hanging at the Extremities of the larger Vessels like so many Bunches of Grapes and the Glands in other parts are apparent but in a Muscle we can discern no such things for it especially when boiled parts into distinct Carnous Fibers To which I Answer That those Glands are nothing else but a Composition of the ends of importing and exporting Vessels and the Reason why we cannot discern the same in a Muscle is this because the Extremities of the Vessels are so fine and consequently so brittle and are contained in the Interstices of so strong and firm Fibers that whenever we endeavour a separation of the Fibers the Glandules are torn away from the Vessels from which they are derived whereas the Fibers which run transverse the Liver easily crumble away being much more weak and less Numerous The Reason why the Muscular Fibers are so much stronger than those that run through the Liver is apparent enough Viz. because the former are the Instruments of Motion and consequently there lies a greater stress of them than on the latter which serve to make the Part a little more compact and to keep the outward Coat from being loose upon it's Circumference Now because it is impossible to separate and remove these Muscular Fibers so as to leave the Sanguiferous Vessels as entire as would be requisite for the exact and certain discovery of their Terminations and because it is certain that these Vessels are divided and subdivided ad minimum that they are interwoven one with another and that a Gland is nothing else but a Composition of Vessels we may rationally conclude they all Terminate in Diminutive Glands The Nerves Veins and Arteries composing and ending in these Glands I shall next Enquire to what end they do all thus meet together The Use of the Nerves in these is the same as in other Parts Viz. to conveigh a Spirituo-saline Liquor from the Brain Which Spirits being Volatile and apt to Ferment when mixed with a Liquor of a contrary Nature are continually sent by the Systole of the Brain into all the Muscles of the Body and being laid down forcibly in the aforesaid Diminutive Glands do there meet with Arterious Blood driven in by every Contraction of the Heart Which two Liquors strongly fermenting together the Animal Spirits do by an Attrition Subtilise Attenuate and Rarifie those Particles of the Succus Nutritius supplyed from the Mass of Blood by which Means their own are much dulled and become less Active for the future and by a Mixture of these Animal Spirits with the rarified Succus Nutritius results a Liquor Different from and of a middle State betwixt the Animal Spirits and the
and Circulates through these Cells in greater or less quantities so Contractions are stronger or weaker or not at all the Fibrous Cells being accordingly Distended Dilated and Contracted in Longitude and when according to our Appetite this Liquor ceaseth to flow into the Fibers in so great a quantity as to Contract the Muscle that matter which before dilated the Fibers is Evacuated as being Superfluous Nourishment so that for the future it runs through in a moderate quantity as before Contraction till their Repletion is again renued to Reiterate Motion If it be asked why this Liquor is not as easily forced backwards out of the Fibrous Cells into the Glandules from whence it came as into the Lymphaeducts and so think there would be no need for Lymphaeducts I answer That if there be no Valve at the inward Orifice of every Duct to hinder its reflux which would be no absurdity to conclude for we see always upon the like occasion Nature hath furnish'd such Places with Valves yet I say if there were none the direct Motion of subsequent Matter from the Glandules would sufficiently hinder the reflux of it and since its reflux is opposed by new matter forced successively after it and since according to the course of Circulation the Matter driven into the Lymphaeducts before it will give way for its expulsion it would be more reasonable to imagine that the matter contained in the Fibers is evacuated qua datur porta rather than qua non datur for when we design the Relaxation of a Muscle though the Liquor successively sent from the Glands does not press forwards altogether as forcibly and in as great Quantities as whilst Contraction is continued yet it follows moderately so as to oppose the Retrocession of any thing I mean moderately as to its quantity for the continual violent concourse of the Animal Spirits and Arterial Blood drive it then into the Fibers almost as violently as when the Muscle is contracted That these Lymphaeducts do thus receive this Subtile Liquor and that for that end they are inserted into the Fibrous Cells I am perswaded because it cannot otherwise be understood how the Matter that stuffs them up and causes Contraction could be drawn out again without a Retrocession through the same Channels by which it was brought in And though the most Learned and Famous Dr. Willis Dr. Ridley and others do allow a Retrocession yet since it contradicts the course of Circulation we must either deny Circulation or reject their Opinions Besides I cannot conceive what other occasion there is for Lymphaeducts in a Muscle since whatever is brought by the Arteries might as well be returned by the Veins as by two sorts of Vessels But for as much as Nature hath made nothing in vain and since there is so great necessity that they should be inserted into the Cells I think it not irrational nor absurd to conclude they were designed for the afore-mentioned end That we may understand a little better the Nature of this Liquor which we have so often mentioned let us consider a little more fully how that Fermentation is carried on in the said Glandules It 's commonly known that when a Ferment is put to a Mass whether Liquid or of a solid consistence whatever is the nature of the Ferment it according to its power always endeavours to render whatever comes within the Sphaere of its Activity as like it as possible So in these Glandules the Animal Spirits fermenting with the Arterial Juice and the Nature of 'em being according to Dr. Willis and Diemerbroeck Spirituo-Saline composed of Volitile Salt and Sulphur they by Reason of their absolute Quality more readily mix with the crude Sulphureo-saline Particles of the Nutricious Arterial Juice and as they are more or less in quantity so they exalt and carry forth into a Flux more or less of that Crude Sulphureo-saline Mass which being by Fermentation subtilized is diluted with a sufficient quantity of Lympha or the watry part of the Serum of the Blood and the Liquor resulting from that Composition is thrust out into the Fibrous Cells That this Lympha might be thin enough to dilute the said Liquor sufficiently it is much attenuated in that Fermentation That there is such a Fermentation that the Nerves are inserted into the Glandules and lay down Animal Spirits as the Principal Cause of that Fermentation that the Arteries lay down Blood together with the aforemention'd Juice and that in those Glands a subtile Liquor is prepared being composed of Animal Spirits and the most rarified parts of the said Succus that neither the Arterial Juice nor the Animal Spirits simply can cause the Contraction of a Muscle but furthermore that it is necessary that this Subtile Liquor should be so prepared and composed as being capable to enter into the Fibers and to contract the Muscle is sufficiently apparent from what hath been said and will more clearly be evinced by what follows And first if there be a Communication of these Vessels as certainly there is then it must needs follow that there is a commixture of their Contents if there be a commixture of their Contents then there is a Fermentation and in that Fermentation it must needs follow that the Animal Spirits will according to their Energie and Activity Subtilize and Attenuate the Crudest Parts of the Arterial juice By a mutual Fermentation there must needs be implyed an intimate Commixture and the Result of that Commixture must needs be different from the Animal Spirits or Arterial juice simply before they are mixed so that the Liquor resulting from the Mixture of 'em may be properly called a Subtile Liquor And accordingly as the Animal Spirits are more or less in quantity to mix with the Arterial juice more or less will be prepared and thrust out into the Fibrous Cells and consequently the Fibrous Cells must be more or less Tumified and the Muscle Contracted as more or less Spirits are laid down in the Glandules So that all I have to Prove is That neither the Arterial juice nor the Animal Spirits can cause the Contraction of a Muscle and then it will follow consequently that there is a Communication of these Vessels and for that end in the aforesaid Glandules It hath often been found that an Atrophea of the Parts will follow the Relaxation a Palsie the Abscission or Ligature of the Nerves leading to those Parts Which sufficiently shews that the Arterial juice it self cannot cause the Contraction of a Muscle without the assistance of the Animal Spirits because when the Animal Spirits cease to flow into the Glandules for want of a dew Fermentation to Subtilize and Prepare a sufficient quantity of the Arterial juice the Carnous Fibers are not only deprived of necessary Recruits and Alimental refreshment so that they must needs waste away and grow Languid but also for want of a sufficient quantity of the Subtile Liquor to distend the Fibrous Cells
to get it forwards Mr. Cowper Mentions an Experiment how by an Injection of Water into the Crural Arterie the Muscles of the Legs renue their Contractions From this he would infer that Muscular Motion is performed by the Blood as a Pondus but tho' his Myotomia Argues it came from an Inquisitive Author yet I rather an fully perswaded that the Blood does not Act as a Pondus because this Experiment pleads against it but to avoid a long dispute I shall only give the Reason of the Phaenomenon Before the injection of this Water the Branches of the Arteries are full of Blood and Arterial juice and when by the mixture of the Water with this juice it is attenuated and driven into the Glands faster than it can be received by the Venous Channels the most Subtile Part is by the force of injection strained into the Fibers and distends 'em so as to Contract the Muscle Perhaps here it will be objected that if the Water can thus pass through into the Fibers what need is there that the Nerves should lay down their contents in the Glandules I answer that the Water is thin and apter to pass through those Ducts than the Arterial juice which is thick and viscid wherefore it is necessary that the Nerves should lay down their contents there to Attenuate and Rarisie this Thick juice I have seen People inclining to a Dropsie whose Blood and Serum was much diluted could move much more nimbly tho' more seebly than some of a healthful Constitution whose Blood and this Arterial juice was thicker and not so much diluted which doth plainly shew that the thinner the Blood is and the more diluted the Nutritious juice the less quantity of Spirits is required to subtilize it and make it capable of passing into the Fibers It may easily be observed that those People whose Spirits are strong and their Arterial juice very thin are Nimble but the Contractions of their Muscles are not so durable as of those whose Serum is of a thicker Consistence For tho' in the former more of the Subtile Liquor is prepared yet by Reason of its Tenuity it 's sooner receiv'd and carried off by the Lymphaeducts which makes the Contraction shorter Those whose Blood abounds with fixed Salts Phlegmatick Humours which too much dull and resist the Activity of the Animal Spirits are always slow and unapt for Motion whereas if the Blood Acted as a Pondus they must be more nimble and strong because the thicker the Blood is the heavier would be the Pondus As Muscular Motion is many ways vitiated by the fault of the Arterial juice or of the Spirits and consequently by the Distemperature of this subtile Liquor so it is very often depraved and accordingly as the Mass of Blood degenerates from its genuine and proper Nature are produced various Diseases or Symptoms of Diseases viz. Cramps Convulsions Palpitation of the Heart Leaping of the Tendons in Fevers c. for a farther illustration of my Hypothesis before I conclude I will give the Reasons of these Phonomaena When by an Abuse of Non-Naturals the Ferments of the Viscera are perverted and by the faults of the Pancreatick juice and of the Spleen an Acid or Austere Salt is carried forth into a flux presently the Mass of Blood is vitiated The Animal Spirits meeting with this vitious Salt and fermenting in the Glands do there cause irregular Explosions of matter into the Carnous Fibers subtilized in that Fermentation whence follow irregular Contractions of the Muscles Why Convulsive Paroxysms come at uncertain times will easily appear if we do but consider the Procatartick Causes amongst which I shall only mention two viz. The Quantity of Morbisick matter irritating Nature to an Expulsion of it and sudden Passions of the Mind The Quantity of Morbisick matter is far greater in some Bodies than in others before the Spirits are able to recover themselves and to endeavour an Expulsion of it In the former Case Convulsions are Universal and seise the whole Body in the Latter Particular the Morbisick matter being accidentally driven more on one Part than another Again in some Bodies it is sooner heaped up being generated in greater quantities The Matter heaped up at the first is very crude and thick and although it be cast forth into and Circulates through the Musculous parts and continually Ferments with the Spirits in the Glandules yet because it is not sufficiently attenuated to be driven forth into the fleshy Fibers till by frequent Circulations and Fermentations it is exalted from it's state of sixedness to a more Volatile no Convulsions succeed Moreover as long as it continues in its state of Crudity the Animal Spirits are much dulled and their Activity quashed by mixing with it but it being at the length subtilized and rarified by frequent Circulations the Animal Spirits recovering 'em selves and violently Fermenting with it in the Glands carry this Vitious juice explosively into the Fibers The Reason why this Motion is Involuntary is be cause it is not produced by a greater quantity of Spirits flowing from the Brain accordingly as the Pores are dilated by our Appetite but by a mixture of Morbifick and Fermentitious Particles which cause Preternatural Fermentations Expulsions of Matter Attenuated thereby Convulsive sits are sometimes brought on before the Morbifick matter gradually arrives at this state of tenuity when upon sudden Passions of the Mind the Animal Faculties quit their Stations and being over-power'd by external Objects can no longer moderate the Emanations of the Animal Spirits The Formal Cause of the Irregular Emanations of the Spirits in these Convulsions is this the Pores of the Brain being shut up to keep out external Objects heap up the Spirits till by Reason of their quantity the Pores can no longer retain them and then the Spirits rush out quà datur portà in a greater quantity and violently setting upon the Crude juice which they meet with in the Glandules strongly Ferment Attenuate and carry it forth into the Fibers of the Muscles wherein the Spirits are thus accidentally laid down The Brain being thus emptied the Pores are shut up again till the quantity of Spirits make way again and so successively follow Convulsive Motions in this or that Part where-ever the Spirits set upon the Crude Morbisick Matter The 〈◊〉 of the Heart as the 〈◊〉 ed Dr. 〈◊〉 has noted 〈◊〉 proceeds 〈◊〉 Convulsive Motion The Reason why the Morbifick Matter only shews it self in this part and at the same time in no other parts of the Body in this The Mass of Blood 〈◊〉 nated with a Morbifick 〈◊〉 and whatever is the Nature of it since it is 〈◊〉 〈◊〉 the whole Body 〈◊〉 〈◊〉 Rationally expect Universal Convulsions as well as 〈◊〉 But this Morbifick Matter being as yet Crude and not of a sufficient Quantity 〈◊〉 〈◊〉 Nature in all the Parts of the Body these Effects are only produced in this Part where a large Quantity of Spirits is
continually laid down to serment with it by which means it is Subdued in this part before it arrives at such a State of Activity of such a Quantity as to cause irregular Fermentations and Contractions in other Parts In a 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 The Muscles continue constantly contracted against our Appetite these Distempers seize People whose Blood is rather of a Vitriolick Tenacious Nature and impregnated with more Fermentative Spirits so that by reason of the Viscidity of the Matter violently forced into the Fibers either the Lymphaeducts are obstructed or by reason of a continual Fermentation Matter gradually succeeds In the Cramp the Fermentation is different from that which is Natural or in other Convulsive Motions that which is Natural being caused by the Animal Spirits preparing a Subtil and Homogenious Liquor In other Convulsions the Animal Spirits ferment with and endeavour to subdue a Morbisick Humour brought and layed down by the Arteries and the Matter thus attenuated is accidentally forced into the Fibers But these are caused by the continual Conflict of the Volatile Animal Spirits strongly fermenting with Fermentative and Elastick Particles of another Nature supplied by the Mass of Blood where both striving to subdue each other the Elastick Particles of the Blood more strongly oppose the Motion of the Spirits and the Spirits them by a contrary agitation and intestine Motion of their Particles and these Two being violently exploded and impetuously leaping into and fermenting in the Fibers cause most strong and painful Contractions The Subsultus Tendinum in Fevers are caused when the Spirits being too much exalted leap irregularly out of the Brain and raise the Fermentation in the Glands so high as to prepare and carry too much of the Subtile Liquor into the Fibers which because it is so very thin easily slips into the Lymphaeducts and makes the Contraction short I shall add the Reason only of one other Phaenomenon which seems more evidently to prove that Muscular Motion depends on the greater influx of Animal Spirits viz. Why the Contraction of one Muscle followeth when the Antagonist becomes Paralytick as in Spasmus Cynicus The Branches of the Nerves being derived from the Brain when the Influx of the Spirits into the Muscles of the one side are hindered they regurgitate and are driven presently in a greater quantity into the Antagonist as by the Loss of one Eye the other by a greater Influx of Spirits becomes more Acute This is evident and needs no further proof Thus I have laid down my Hypothesis of the Formal and Efficient Causes of Muscular Motion and how it is vitiated or depraved which I the more willingly commit to the Judgment of Learned and Competent Judges with due Submission because it seems to me to answer Natural Ends and to account for the several Phaenomena without the Difficulties Enormous Motions and Impossibilities which usually attend Hypotheses on this Subject not doubting but it will give satisfaction till one more probable and plausible shall succeed FINIS Books lately Printed for and Sold by A. J. Churchill at the Black Swan in Pater-Noster-Row A View of Universal History from the Creation to the Year of Christ 1695. wherein the most memorable Persons and Things in the known Kingdoms and Countries of the World are set down in several Columns by way of Synchronism according to their proper Centuries and Years By Francis Tallents sometime Fellow of Magdalen-Colledge Cambridge The whole graven in 16 Copper-Plates each 15 Inches deep and 22 broad bound up into Books the Sheets lined A Work of great Exactness and Curiosity Price 16 s. A Compleat Journal of the Votes Speeches and Debates both of the House of Lords and Houses of Commons throughout the whole Reign of Queen Elizabeth Collected by Sir Simonds Dewes Baronet and Published by Paul Bowes of the Middle-Temple Esq The 2d Edition Fol. The Works of the famous Nicholas Machiavel Citizen and Secretary of Florence Writen Originally in Italian and from thence faithfully Translated into English Fol. Mr. Lock 's Essay concerning Humane Understanding The Third Edition with large Additions Fol. His Thoughts of Education Octavo The Fables of Aesop and other Mithologists made English by Sir Roger L'Estrange Kt. Fol. Two Treatises of Government the first an Answer to Filmer's Patriarch The latter an Essay concerning the true Original Extent end of Civil Government Oct. Notitia Monastica Or A short History of the Religious Houses in England and Wales c. By Thomas Tanner A. B. Octavo The Resurrection of the same Body asserted from the Tradition of the Heathens the Ancient Jews and the Primitive Church With an Answer to the Objections brought against By Humphry Hody D. D. Bishop Wilkins of Prayer and Preaching Enlarged by the Bishop of Norwich and Dr. Williams Octavo Sir William Temple ' s History of the Netherlands Octavo Miscellanea Octavo Dr. Patrick's New Version of all the Psalms of David in Metre Twelves Two Treatises of Natural Religion Octavo Gentleman's Religion with the Grounds and Reasons of it In which the Truth of Christianity in general is vindicated its Simplicity asserted and some Introductory Rules for the discovering of its particular Doctrines Precepts are proposed By a Private Gentleman Sermons Preached by Dr. R. Leighâ—on late A. Bp of Glasgow Published at the Desire of his Friends after his death 〈◊〉 his Papers written with his own Hand The Second Edition 〈◊〉 The End The Usefulness of Muscular Motion as it tends to the maintenance of life With respect to the Soul and its Functions A Muscle is a Noble part Dr. Willis's Opinion examin'd No Elastick Spirits laid up in the Tendons Nor instinct sent from the Brain because Either it implies that the Spirits are Intelligent Or that Spirits of a Different Nature are sent from it The Matter is not Intelligent No Spirits of a different Nature are sent from the Brain No active Principles heaped up in the Fleshy Fibers Nor retrocession of subtile Matter into the Tendons Mr. Cowper's opinion examined The Blood does not act as a Pondus The First Argument A Second A Third A Fifth A Sixth Dr. Ridley's Opinion examined The common Postulatum is not to be allowed There is no Retrocession of a Fluid from the Autagonist Nor is it forced out so as to cause a Vacuum Of the Structure of a Muscle The formal cause of the contraction of a Muscle Vessels implanted into a Muscle Their distribution And terminations in small Glands Proved What a Gland is Why they cannot be discerned The Use of the Nerves And Arteries inserted in the Glands To prepare a Liquor different from the Spirits or Succus The Use of it The Reason of Tonick Motion Objections Answered The Use of the Lymphaeducts The Nature of the Liquor consider'd and the manner of its preparation By Fermentation Proved The Arterial juice simply cannot cause the Contraction of a Muscle Nor the Animal Spirits Because the Arterial juice cannot pass into the Fibers till prepar'd by the Spirits The Reason of Involuntary Motion Proved How it comes to pass that the Systole of the Heart is interrupted with such frequent Diastoles Why the Muscles serving to Respiration are subject in some measure to our Appetite Why old People are subject to a trembling of their Head or Hands Another Phaenomena Explained A Third A Fourth A Fifth A Sixth The Reasons of Convulsions 〈◊〉 〈◊〉 〈◊〉 〈◊〉 〈◊〉 Of the Cramp Of the Subsultus Tendinum in Fevers Of a Spasmus Cynicus