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
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
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
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
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
carry on the resemblance a little farther I soon discovered the disparities to be so many and so great that it was impossible to reconcile them into a just Analogy Whereupon condemning the extravagance of my fancy I soberly concluded that the Heart of an Animal is an Engine never to be imitated by human art and I found my self more inclined to applaud the judgment of that prodigy of Mathematical knowledge Archimedes of Syracuse for never attempting to counterfeit the motions of the heart than to admire his wit shewn in making a Sphear of Glass Athan. Kircher denies that any part of it was Glass but only the out-side that men might discern the wheels and motions within which represented the perfect order and motions of the Celestial Bodies and which Claudian describes in one of his Epigrams Now if we desire clearly to understand this inimitable Excellency of the Machine of the Heart and in what Proprieties of it the same doth chiefly consist we shall be obliged well to consider two things neither of which hath yet been explicated by us and without a due explication of both which all that we have hitherto said concerning the motion of the Heart will be maimed and unsatisfactory These are the Mighty and incredible Motive force of the Heart by which it expresseth the bloud out of the Ventricles and the Efficient Causes of its Motion Things so worthy to be known that I need not deprecate your impatience most Candid and accomplished Auditors if I detain you a few minutes longer while I enquire into them As to the FIRST therefore viz. The admirable Motive force of the Heart Since the round and Conical Figure of the Heart doth not permit us to attempt the measuring of its Motive power by the same way by which the most Learned Alphonsus Borellus hath with singular sagacity measured the forces of very many other Muscles of Mans body namely by weights suspended by them and since therefore in this disquisition we cannot from the effect procede to the knowledge of the cause we are compelled from some other Sign to raise a probable conjecture whence we may investigate the greatness of the effect And this Sign shall be the Similitude and Analogy which the Muscule of the heart seems to hold to other Muscles of the same Animal Let us then with the same excellent Mathematician Borellus in whose footsteps I now again tread suppose that all even the least Fibres or little Machines of the same or divers Muscules in the same Animal are equally strong and exercise an equal motive force in the same time in the state of health And because equal bulks of two Muscles contein equal multitudes of the least Fibres it follows that if we have foreknown the total motive power of one of the two equal Muscles we shall be able thence to conjecture what is the total power motive also of the other Therefore the fleshy bulk of the heart being of almost equal magnitude to the bulks of one of the Temporal muscles and of one of the Masseters and Borellus having demonstrated to us the total motive force of those two muscles we may probably infer that the motive force of the heart is equal to that which those two muscles shutting the mandible exercise Now because no intire Fibre of these two muscles is less than two inches long taking all the Fibres one with another that the excesses of the longer may compensate the defects of the shorter and because in an inches space of every single Fibre we may imagine more than twenty little Machines or Rhomboid Pores contained like the links of a chain in a Watch or the Meshes of a Net in a row one above another let us notwithstanding suppose no more than ten smallest Fibres to be conteined in that space therefore in the length of every one of the Fibres that compose the said two Muscles there will be conteined more than twenty of those most minute Machines And since the weight of 150 pounds may be suspended by one single Stratum or Layer of these small Machines of the same Muscles therefore that we may have the whole force that Nature exerciseth in those Muscles the force of that one Layer viz. that which is able to sustain 150 pounds ought to be twenty times multiplied Wherefore the whole force that Nature exercises to dilate all the Rhomboid meshes or pores of the said two Muscles when they act is greater than the force of 3000 pound weight and would if applied to the opposite end of the beam of a balance preponderate If then every most minute Fibre of the Heart exerciseth in the Systole of it a force equal to that which every Rhomboidal Machine of the Temporal or Masseter muscle makes when they act as most certainly it doth the motive power of all Fibres of the Muscles in the same Animal in the state of health being equal and if the multitude of least Fibres contein'd in those two Muscles be equal to the multitude of most minute Fibres contein'd in the Muscle of the Heart as the visible equality of their magnitudes warrants us to suppose it to be we may thence deduce this conclusion that the force which all the most minute Fibres of the heart when they are swell'd exercise to constringe the Ventricles i. e. when they act all together exceeds the force of 3000 pound weight and would preponderate if it were applied to the contrary end of the beam of a just balance Quod erat demonstrandum And thus have I given you a summary of what Borellus hath from a long chain of most ingeniose Propositions and Theorems in fine inferred I come therefore to the. SECOND and last considerable proposed to be inquired viz. the Efficient Causes of this so wonderful Motive force of the Heart These seem to be no more than two of which one is immediate the other mediate As to the the former viz. the immediate cause of the hearts Motive Power we are not to expect to learn either what it is or whence it procedes from the doctrine of the Ancients For they having observed that the heart was not as all the other Muscles of the body are moved ad arbitrium voluntatis at the command of the Will not only named the motion of those Voluntary and the motion of this Natural as they had good reason to do but also conceived and taught the cause of the motion of the heart to be divers from the cause of the motion of the rest of the Muscles and accordingly constituted and assign'd to the heart a certain blind and unintelligible Pulsifick Faculty whereto alone they ascribed as well the diastole as the Systole thereof which they had no just reason to do To evince this their palpable error I will assert this PROPOSITION That the immediate Motive cause of the heart is the very same with that by which the Muscles of the Limbs are moved Voluntarily First it is most evident to sense that
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
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
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
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
other nerves especially when their Function and office is different from that of all other nerves and no less than the Pulsation of the heart i. e. the conservation of life itself depends upon that difference I am not I confess so happy as certainly to know in what singular Artifice the difference doth consist but am notwithstanding fully convinced there is some difference And if so why may not the difference consist in such an Artifice as that which I have here supposed and described since the same is not only possible but facile also and sufficient to produce the effect required viz. the perpetual instillation of the roscid liquor drop after drop into the Fibres of the heart If this be granted the mighty Difficulty is solved If not I say Secondly That the multitude of Nerves elonged from the Brain to the Heart ought to be considered What reason can we imagine Nature to have had when she furnished the Heart with so many nerves more than are inserted into any two nay three Muscles even of the first rate Certainly she did it either for the more exquisite Sense or for the more copious nourishment or for the stronger motion of the heart for no fourth cause can be found The first is improbable because it doth not appear that the Heart excells any other Muscle in the sense of touching or feeling and because there seems to be no necessity of its being endowed with much of sense whether we respect the action of it which is not perception but Pulsation and that too with incredible violence such as is inconsistent with delicate and exquisite sense or whether we reflect upon the secure Situation of it which is in the Centre of the cavity of the Thorax where it hangs free and defended on all sides from harm and offence either from within or from without The Second also is improbable because the bulk of the heart holds no just proportion to the multitude of nerves inserted into it and there are many Muscles of far greater magnitude which yet are plentifully supplied with nourishment by much fewer nerves The third therefore is true and by consequence serves to disintangle our Hypothesis from the chords of the Difficulty proposed For so great a number of nerves importing into the Heart much more of the nutritive liquor than can be thought necessary for its nourishment of what use can the overplus be unless to maintain the perpetual motion of it And in this also there is a manifest difference betwixt the Heart and all other Muscles and such a difference as may be brought for one reason why no other Muscle but the Heart hath a Pulsation Thirdly I say that the aptitude of the Heart to Pulsation doth consist in its proper Fabric and conformation in its Conical Figure in its cavities within in the disposition and configuration of its Fibres in a word in its whole Mechanism which I have formerly described and which is far different from the Mechanism of any other Muscle whatsoever So that if there were no singular Artifice or knack in the structure of the Cardiac Nerves or if these nerves were fewer in number yet might the heart be apt for Pulsation of which all other muscles are incapable as wanting the like Mechanic conformation No wonder then if Pulsation be proper to the heart only though the Fibres of all other Muscles be of the same nature with the Fibres of the Heart though the Efficient Causes of the Motion of all other Muscles be the same with those of the Motion of the Heart and though they as well as the heart act by the contraction of their Fibres Now if no one of the three Reasons here by me alledged why the motion of Pulsation is not common to all the rest of the Muscles taken single be thought sufficient yet if ye please to conjoyn and twist them all together into a triple chord ye may then perhaps find them strong enough to pluck up the proposed Difficulty by the roots But hold a minute or two Have I not through hast or want of due circumspection run my self into the Bryers of a contradiction Did I not in my last Proposition affirm that the Mediate Cause of the natural Motion of the Heart differs in some respect from that by which all the rest of the Muscles are incited and invigorated to voluntary motion and have I not in the Paragraph immediately preceding this said that the Mediate cause both of the Motion of the Heart and of the Motion of all other Muscles is one and the same viz. the Succus Nervosus derived from the Brain Where then is the difference presumed I answer therefore that the difference lies not in any change or alteration of the nature and qualities of the Succus Nervosus itself which I grant to be the same utrobique on both parts but only in the divers Modes of its effusion from the Brain Into the heart I suppose it to descend through the Cardiac nerves gently slowly and by way of instillation drop after drop but into the rest of the Muscles I suppose the same to be immitted with great force and velocity swift as Lightning at the command of the Will And this seems to be sufficient to constitute a difference where the same cause used by Nature diversimodè and in Organs of different conformation produceth so different effects and consequently to extricate me from the Bryers ¶ ⸫ From which as well as from the former impediments being now at length free I come in the next place to establish the grand Pillar upon which the whole weight of this my rude structure relies that is to make it appear to be not only possible but also probable that a few little drops of liquor instilled into the Fibres of the heart should only by causing them to swell or by dilating their Pores abbreviate them with a force great enough to make a constriction of the heart This if I shall be able to do I shall not despair of finishing my Building as I at first designed for the remaining part of my work will be little and easie As for the Possibility of so great an effect from a cause that seems to be so weak and inconsiderable that may be without much difficulty proved from the just Analogy or similitude of this effect to many other as great if not greater effects commonly observed to arise from the like Causes For Mechanic Examples of this kind are every where so obvious to sense and so numerose that only to enumerate them would be a task hard and tediose Out of so vast a multitude therefore I will for brevitie's sake select only two such as are not only pertinent and adaequate to my subject but also in themselves eminently remarkable The First is of a new Cable which upon wetting will very much swell or become thicker shrink and shorten itself beyond the belief of any but a Mariner And Galilaeus hath well observed this swelling and
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
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