more readily to it's Motion upwards being less compact above then below I shall produce two or three Instances which prove that if it had but less Liberty to ascend by the Opposition of some other Body then to descend it would as naturally fly downwards as it does now upwards when it is otherwise and I shall also prove that if it had but an equal Resistance on each side it would expand orbicularly And First that if Flame had but an equal Resistance from ambient Bodies on each side it would expand Orbicularly will be proved by this Experiment viz. fill a hollow Globe with Gunpowder one side of which is a little thinner than the other and whatever way that thin side is turned whether down upwards or horizon-ward the Gunpowder will expand and break out that way Secondly to prove that if there were but more liberty for the descent than ascent of it Flame would naturally fly downwards we need but shoot a Gun off with the Mouth downwards for the explauded Gunpowder finding an open and easy Passage downwards and being resisted upwards and on each side it naturally descends But some perhaps that do not throughly understand why a Thing is said naturally to ascend or descend may be unwilling to believe that when a Gun is shot downwards the Motion of the Flame is a natural Motion but may rather think it Preternatural But that it may appear that it is as truly a naral Motion in Philosophy as the ascending Motion of it I shall consider why Flame may be said naturally to ascend Flame then is said naturally to ascend because it is the Nature of it for the most Part to do so which is as much as to say the Nature of Flame inclines it to ascend how the Nature of it inclines it to ascend I have already shown and that there are the same Reasons why the descending Motion should be termed Natural will easily be proved for as it is natural for it to ascend as long as it hath only the Air to oppose it's Motion so it is it's Nature to descend when the Order of Opposition is changed and the latter is as much a natural Motion as the former all that diversifies the tendency of Flame being those accidental Circumstances which are about it and as a Ball cast against the bottom of a Room rebounds upwards and when it is thrown against the top of it as naturally flyes down so Flame being in a brisk Motion naturally flyes up or down as the Parts of Matter it striks against resist it and cause it to fly back from them HAving made this short Digression I shall proceed next to examin Diemerbroek's Opinion who thinks that the vital Spirit by reason of it's Volatility always endeavouring to fly away does continually agitate those grosser Particles of the Blood with which it is entangled and detained from flight and is diversly vibrated and beat back and so the whole Mass being kept in a continual fermentative Motion there is a Heat produced in it which in a greater Agitation is greater c. And so differs according to the different Degrees of Agitation All that I shall or need to take Notice of here is that that Agitation of Particles which he says causes the Heat of the Blood rather produces a Sensation of Heat by affecting our Senses in their Motion than produce that which we call Heat in the Blood But to know the true Reason of the Heat of the Blood we must understand how those Particles are put into Motion which by affecting our Sensory cause such a Sensation So that he seems to me to say no more then that that which hath a Power to cause Heat is the Cause of that Power when he ought in order to explain the Heat of the Blood to have shown from whence that Power proceeds the Reason of which I should have taken in some measure for the Reason of the Heat potentially in the Mass of Blood but from what he hath said it appears that he hath not explained the true Reason of the Heat of the Blood so plainly that I need say no more against it Dr. Henshaw thinks that the Dissimilitude betwixt the Chyle and Blood is so great that it becomes immediately the Cause of an extraordinary Ebullition upon their mixture together which is very much increased by the reciprocal Motion of the Lungs whereby the Blood is wrought into a froth by that time it gets into the left Ventricle of the Heart Which sudden Excess of Heat he thinks not unlike what happens upon the mixing of several Chymical Liquors together for the Heat often becomes so great that they often endanger the Vessels that contain them But he might as well have said that there is so great a Dissimilitude betwixt hot Blood and cold Milk that as soon as the Milk is mixed with it it will cause an extraordiary Ebullition and that by exposing them to the Air running them through Pipes the Heat would increase but this is so plainly false that it needs no other Arguments but Reflection to convince the weakest Reason And he might equally as well conclude that Water would kindle a Fire and encrease the Flame of it because Oyl will as that Chyle will put the Blood into a Heat because Oyl of Turpentine and Spirit of Wine will grow hot when mix'd together but the Conclusion being manifestly absurd I shall in the next Place endeavour to show the Reason of the Heat of the Blood as evidently as possibly I can FROM what I have already said in Answer to Dr. Willis's Opinion it sufficiently appears that whether we say the Blood grows hot per admotum Calidi Accension or any other way it is no more then to express the same Thing several ways or to make Words different in Sound to express one and the same thing But as all that have writ on this Subject have made choice of a different Name to signify the Heat of the Blood by whilst some would have it done by Accension others by Attrition c. so they have by that means rather disputed about Names and Words than any real and fundamental Difference in their Opinions I shall not here enter into a dispute whether the Blood when it becomes hot may most properly be said to grow hot or it's Heat expressed by any one of those Titles they have been pleased to signify it by for as in discoursing about the constituent Parts of a Man it is not necessary to fix any Name upon that Man but whether it be Thomas Robert or William the constituent Parts of him if he be a perfect Man will still be the same so in discoursing concerning the Heat of the Blood and considering the principal Cause or Agent and the more remote and accessory Causes it is no matter at all whether the Consequence of these Causes be signified by the word Accension Attrition or Fermentation because the Difference of the
any thing as one that 's in a Fit of the Epilepsie but our Bodies being accustomed to it and it being made agreeable and consistent with Circulation of the Blood becomes less troublesome when we have occasion for Extraordinary Respirations For these Reasons it is plain why the Lungs ought to be in a continual Reciprocal Motion the first of which is self-evident and needs no further Proof and the second is sufficiently evinced by the Consequences that follow when this Lympha is not evacuated When it is too thick or too much in Quantity or on the other side the Air which we breath is too thick and moist and it is not duly carried off there follow Obstructions of the Ducts of the Trachea from whence proceed Symptoms of an Asthma Orthopnaea and Duspnaea some sorts of Phthisicks and a great many more dangerous Symptoms For when it is too thick it sticks fast to the Coats of the Lungs and not being easily enough mixed and incorporated with the Air the Quantity of it encreases till it stuffs up the Cavity of the Lungs and when it is too much in Quantity though it be thin enough yet the Air being not able to carry it off fast enough it runs down the sides of those tender Vessels and by a gentle Irritation raises a tickling Cough Lastly when the Humor that moistens the Lungs is almost Natural as to Quality and Quantity yet if the Air be thick and moist it being so much impregnated with it's own Moisture is incapable of carrying off the Moisture supplyed by the Serum of the Blood whence People that are inclined to Obstructions of their Lungs in foggy and moist Air find them more oppressed that Moisture which ought to be carried off being left behind But if we consider further the Use of the Lungs with respect to the Body we shall find other Reasons not only why it should be in a constant Motion but also we may understand why we cannot live without a continual and free Circulation For in respect of the Body the Lungs seem in some Measure to perform the Office of another Heart and as the left Ventricle of the Heart contracting sends out the Blood into all the Parts of the Body by the Ramifications of the Sanguiferous Vessels so the Lungs contracting force the Blood contained in the Sanguiferous Vessels which are distributed through their Lobes into the left Ventricle of the Heart and the left Ventricle being by that means more vigorously dilated and more plentifully filled with Blood a larger Quantity of it is forced out into the Aorta and consequently the Blood in the Branches of the Aorta is more copiously pressed by subsequent Matter into the Roots of the Vena Cava and so forwards into the right Ventricle of the Heart so that by the help of the Lungs the Dilation of the left Ventricle of the Heart is immediately and the Dilation of the right mediately promoted That the Lungs thus promote the Dilation of the Ventricles of the Heart it is very reasonable to believe not only because it is self-evident but because otherwise it will be very hard to conceive since the Motion of the Heart is only Contraction and the Dilation of it's Ventricles only a Cessation from that Motion how the Blood is forced into them with Vigour enough to distend their Cavities For there is so little Reason to expect that they should dilate of their own Accord that we should rather believe they would be continually contracted since all the Weight of Blood contained in the whole Sanguiferous Vessels of the Lungs could not possibly dilate them without some other force to help it for the Substance of the Heart being contracted and the Cavity of the left Ventricle so considerably diminished so small a Portion of blood as hath Liberty to press against it's Orifice would make but a weak Pressure and much too small to dilate the Ventricle in so little time as intervenes the successive Contraction besides the Heart having no Tendency at all to dilate it self since that would make it unapt to yield to Contractions we must suppose that a Part of such Substance cannot easily be dilated but would require some Force greater then can be supplyed by an inconsiderable Pressure of Blood faintly intruded by almost nothing at all But the Lungs being almost in a continual Contraction in respect of the Sanguiferous Vessels and consequently squeezing out the Blood contained in them help to dilate and extend the Left Cavity of the Heart and consequently the Right That the Dilation of the Ventricles of the Heart is only a Resolution or Cessation from Contraction is allowed and agreed upon to prove then that the Venal Blood cannot return with Force sufficient to dilate the Right Ventricle of the Heart nor is sufficiently able duly to extend the Left in order to the next Contraction by that force it received from and was put into by the former Contraction but is assisted by the Lungs we may easily perceive For not only the Blood in it's Vessels but even any Liquor being forced through Pipes whose Cavities encrease the further they run from their narrow and small Original always moves with less force the farther it goes So that although in every Systole the Blood should be forced forwards from the left Ventricle by a successive Pressure of subsequent Matter and the Motion should be strong enough to make it circulate briskly through the narrow and capillary Twigs of the Arteries yet when it came into the Veins it would move much more slow and by that time it came to the Heart again would want Force sufficient to dilate the right Ventricle and the right Ventricle being not duly dilated so little Blood would be squeezed into the Lungs that the Left would want a Supply of Blood to dilate it and consequently the Pressure of Blood through the Aorta and Vena Cava would be so weak that the next Dilation of the Right Ventricle would be weaker than the former and so Circulation would gradually decrease But that weak Motion of the Blood into the Right Ventricle being encreased by the Force of subsequent Matter from the Left the Motion of the Blood into the Lungs is consequently more plentiful and as it passes through them is violently forced into the Left and so on and by that means as I said before the Lungs distend the Left immediately and consequently the Right mediately That the Motion of the Blood is thus weakned by so long a Course in the Veins is further evinced if a Vein and Artery be open'd at once for the Blood runs out of the Artery much more forcibly and indeed it would be reasonable to think it so though it were not manifest by so plain an Experiment for if Water in a Cistern be put into a violent Motion at one end the further it runs along the less violent is the Force of it And it is further evident that the Motion of
the Lungs does assist the Dilation of the Heart as I have shewed by stopping the Breath of any Animal which for want of free Circulation presently dies and not because the Flame of the Blood is by that means extinguished for as long as the Lungs duly perform Respiration and the Heart violently contracts and drives the Blood contained in it's Ventricles forcibly out that Motion of the Blood being by a continued waving Pressure decreased is enabled by the Assistance of the Motion of the Lungs to dilate the Ventricles of the Heart with a sufficient Quantity of Blood to be forced out the next Contraction but as soon as the Lungs cease to assist the languid Motion of the Blood in dilating the Ventricles it is not only less plentifully forced successively thus into the Ventricles of the Heart but by a weaker Pressure of the Contents of them thrust out each succeeding Pulsation the Arterial Blood is less plentifully driven forwards so that the whole Mass circulates flower by degrees and also the Animal Spirits being driven less violently into the Muscles that Supply of Spirits separated in the cortical Part of the Brain being not so powerfully thurst after by an equal Succession of Matter the Fermentation in the Glands is weaker and consequently the following Contractions gradually decline both in Number and Vigour till at the last they cease But if before the Circulation of the Blood be quite stopped that Animal be again permitted to breath the contractive Force of the Lungs drive Blood more forcibly into the left Cavity of the Heart so that the next Pulsation a greater Quantity of Blood is forced into the Arteries which makes a more considerable Protrusion of Blood into the Muscular Glands and also of Spirits through the Nerves by which means the Thorax contracting more violently forces the Blood in greater Quantities into the left Ventricle of the Heart and the Motion of the Heart at the same time increasing raises Circulation to it's natural Force by squeezing Blood forwards into the Right and so successively From hence it appears that the Blood is forced into the Ventricles of the Heart by the help of the Lungs for if when the Motion of the Lungs is obstructed the Systole and Diastole of the Heart ceaseth in a short time it must needs follow that it is in some measure preserved in that Motion by them and it is further proved because the Motion of the Heart does not only sooner stop when Respiration ceases but also because it is increased by a renued Respiration and any one that would be further satisfied of the Truth of it let him hold his Breath a considerable time and he will find his Pulse gradually decay which is again renued by reiterated Breathing But though from hence it may appear that the Motion of the Heart is promoted by the Assistance of the Lungs yet it perhaps may be a Question how this Defect is supply'd in unborn Infants and how their Blood circulates since then their Lungs do not perform the Office of Respiration To which I answer that in an Infant before Birth the Placenta supplys that Defect for that additional Force which the Infants Blood receives from the Motion of Nourishment violently forced into the Umbilical Vessels by the Pulsation of those Arteries that separate it from the Mother's Blood in the Womb do prove equivalent and supply the Office of the other but as soon as the Circulation of the Blood ceases to be promoted by a Sepaparation and Protrusion of that Juice it immediately if unborn dies and after it is born hath a continual Necessity of Breathing as long as it lives Where it is to be noted that as in one that breaths the Lungs more immediately assist the left Ventricle so in one unborn the Placenta more immediately promotes the Dilation of the right Now although it from hence appears that the Motion of the Heart is promoted by the reciprocal Motion of the Lungs yet it does not wholly depend upon it for if it did the Motion of the Heart would as suddenly stop as that of the Lungs but since it does but partly depend upon it Circulation declines by degrees upon the stopping of it But that it may be better understood how the Lungs promote Circulation I shall next shew that the sanguiferous Vessels in the Lungs are not only contracted by the Contraction of the Thorax but also in every Inspiration And since it is known that the Bladders of the Lungs are encompassed about with the small Twigs and minute Ramifications of sanguiferous Vessels every Systole of the right Ventricle of the Heart these must needs be filled and distended with Blood and if so consequently that Blood must needs be forced by the Contraction of the Thorax through the Vena Arteriosa with a considerable Force and so be driven into the left Ventricle of the Heart with more case where we may by the way take Notice that the Blood in the Arteria Venosa from the Orifice of the right Ventricle is not only by that means thrust into the minute Vessels of the Lungs more easily but also the Blood that is to be forced forwards by the next Pulsation is more readily received by the Vena Arteriosa and the Ventricle more easily contracting when the Vessels of the Lungs are thus emptied by a Contraction of the Thorax than if they were distended that subsequent Matter in the depending Parts is received and driven after it with less difficulty the resistance that distended Vessels would make to the Egress of it being thus prevented by the help of the Lungs That the Blood is thus forced out of the Lungs into the Ventricle of the Heart is not only evident from Reason but also Experience for in violent Coughing where the Lungs are almost in a continual Contraction the Blood is more violently driven into the Habit of the Body that it is forced into the Face visibly appears and that it also flows into the Habit of the Body is evident in People that are let Blood which by coughing much is plentifully forced out of the Orifice and that the Contraction of the Lungs in coughing can no otherwise force the Blood into the Habit of the Body but through the left Ventricle is very plain and Lastly that not only the left Ventricle is by that means further dilated but consequently the right by the Assistance of the Lungs is manifest because Circulation is presently quickned by coughing so that this one Phaenomenon proves all that I have asserted concerning the Use of the Lungs with respect to the Heart But it may here also be questioned how the Lungs supply the Heart in Inspiration when the Cavities of the Lungs are dilated To which I answer that though the Cavities of the Lungs are dilated in Inspiration yet the Bladders which are swelled and dilated with Air even then make a moderate Pressure upon and consequently a Contraction of the Blood Vessels that are
the Heart and from the Heart to the Extremities of the Vessels again being very short before there can be any sensible or considerable Decay of it the Blood is anew fermented in the Glands and so by a continual Circulation the Heat of the Blood is preserved and because by this time the Animal Spirits mixed in the first Fermentation with the Blood are almost spent being incorporated with it and because Part of it is continually separated in the Brain it meets a second time with new Supplies and also by repeated Fermentations is more impregnated with Spirits as well as digested and ripen'd to a higher Degree of Maturity Thus I have given an Account how the Heat of the Blood is carried on in the Vessels that it might more clearly appear how the Original Cause of Heat is principally in the Glands That the Animal Spirits are put into an elastick Motion in the Glands I have before proved by the grosser Particles of the Blood and that the Blood so fermented is successively cast out into the Veins is plain enough to any one that does but understand Circulation to prove then that the Blood being thrust out of the Glands does by a further Expansion of those Spirits for a while increase the Fermentation and that when the Vigour of the Spirits is spent it will gradually decay we need but take Notice how Fermentation is begun and carried on in other Liquors for when oyl of Vitriol and Spirit of Armoniac Salt are mix'd together the Parts of each being in some measure mixed and put into Motion by dropping the one into the other they presently begin to ferment which fermentation is gradually exalted till by a frequent Collision and Attrition the most Fermentative Parts fly away or their Vigour is lost and then Fermentation gradually decreaseth and in like manner all other Liquors that for a time ferment with a sensible Heat But if possible it will further appear that the Original Principal Cause of Fermentation is in the Glands if we do but consider how Fermentation is carried on in a dying Body For in a Body that is about to die the Vigour as well as Quantity of Animal Spirits being diminished and those too being less vigorously grund betwixt the Parts of the Arterial Blood expand so weakly that they scarce agitate the Mass of Blood sufficiently to preserve it's Heat but as soon as the Blood and Spirits cease to circulate the Heat of the Blood presently grows milder till at last it is quite extinguished Now if when the Fermentation is weak the Heat of the Blood is more remiss and depressed and when Circulation is stoped it consequently ceaseth it must needs follow that the Animal Spirits are the Cause of that Fermentation and that it is promoted by driving those two Liquors forcibly together and that the Fermentation is chiefly caused in the Glands is plain because when the Spirits and Blood cease to be driven together and there fermented the Heat of the Blood decreaseth and that it is not in the Vessels is evident because after Circulation is stoped it presently declines whereas if it were caused in the Vessels it would continue after Death as well as before since it then hath the same Matter though it wants Circulation and a forcible Mixture and what I have shewed to be the Consequences of it I shall only bring one Argument more to prove that the Heat of the Blood depends upon the Attrition and Fermentation in the Glandules which may be inferr'd from this common Observation that the Heat of the Blood is encreased by all violent Motion For upon all violent Motion a larger Quantity of Animal Spirits being sent to the Parts to be moved in order to prepare a greater Quantity of subtile Liquor to distend and dilate the Fibres the Fermentation is not only raised higher in the Glandules but the Motion of the Heart being thus accidentally increased quickens the Circulation of the Blood so much that before the vigorous Motion of it's Parts which was raised in the precedent Fermentation is spent it is again renued But the Circulation of the Blood is not only quickened by the Contractions of the Heart but also by the frequently repeated Contractions of the Muscles For the Heart contracting sends it out into the musculous Parts and again those Muscles drive it sooner and more forcibly back upon the Heart from whence it appears that both the Heat of the Blood is encreased by being often fermented in those Glandules and consequently that it depends on the Mixture and Fermentation of the Animal Spirits and Arterial Blood From hence it is manifest how far Circulation is beneficial in carrying on the Heat of the Blood and if we consider the Reason which I have given of Muscular Motion we shall see that as Fermentation depends on Muscular Motion so Muscular Motion depends on Fermentation so that as I said before there is a continual Chain and Circulation of Causes as well as Humors in a Man's Body To proceed therefore to the second Objection I supposed some might raise viz. Whether this Fermentation can be carried on in so short a time as a continual and quick Circulation will admit This does not only appear Possible from evident Matter of Fact but also if we consider that in much less Time than what is allowed for Fermentation in the Glandules if a Spark of Fire be put to Gun-powder it immediately puts it's Parts into an Explosion and that the Blood not only ferments in so short a time but that it may prepare that subtile Matter which circulates through the Muscular Fibres we may with a great deal of Reason believe if we do but take notice that warm Milk if it be but forcibly milked into Vinegar it presently is separated into two Parts viz. Curd and Whey If then by mixing these two Liquors they cause so great a Change on one another I cannot conceive any Reason why Part of the Animal Spirits fermenting with the Blood may not as soon be mixed with some Part of the rarified Succus Nutritius and forced forward into the Fibres But from what I have said it appearing that the Heat of the Blood Is caused in the Glandules by Fermentation and how it is continued in the Musculous Parts I shall in the next Place consider in what Parts it is most vigorously fermented which will appear only by considering where the Spirits are most plentifully laid down for if Fermentation depends on and is chiefly caused by the Animal Spirits as I have shewn then it must needs follow that the Heat of the Blood is most promoted in those Parts where Animal Spirits are most predominant And having proved that in order to prepare that subtile Liquor which causes Contractions of the Muscles a greater Quantity of Animal Spirits is sent there it will follow that the Blood grows hotest being most vigorously fermented in those Parts that are in Motion and
then it will follow that the Heart being a Part in constant Motion and that Motion proceeding from a successive Supply of Spirits the Blood must needs acquire the most considerable Degree of Heat in the Substance of it But although I say that the Blood for these Reasons acquires a greater Heat in the Heart then in any other Part I would not be thought to mean that it grows hot so in the Ventricles of the Heart For the Use of the Heart being only to force the Blood out of it and by dilating to receive it in again for another Expulsion and so to keep it in Circulation it can get no great Heat there since it wants Spirits to ferment with it but I only mean that considering the Substance and Dimensions of the Muscular Part of the Heart and that small Portion of Blood contained in the Arteries dispersed through it that that Blood acquires a greater Heat than that Quantity of Blood does in another Part that is not in Motion But there being besides Muscular Parts many considerable Internal Parts in a Man's Body in which a great Number of Blood Vessels are distributed it perhaps will be asked whether Fermentation be carried on in these too To which I answer that Animal Spirits and Arterial Blood being either mediately or immediately laid down in them all there must needs be a Fermentation which being proved upon such Premises by what I have already said there is no need I should repeat it again But since Anatomists have not as yet discovered Nerves to be distributed through the Liver although Blood be communicated to it by the Vena Porta which supplies the Office of an Artery to the Liver it perhaps may be doubted whether Fermentation is carried on after the same Manner there and consequently whether the Office of the Liver be performed by Fermentation or not that it is I shall shew hereafter and also how the Glands in that Part are supply'd with Spirits From what I have hitherto said it appears what are necessary to continue the Heat of the Blood and also what is the Cause of it For First It is necessary that the Animal Spirits and Blood should be in a continual Circulation that being forcibly driven together their Particles might be intimarely mixed one with another And Secondly That the Animal Spirits should be grund betwixt the Parts of the Mass of Blood that they may be thereby rarified and expanded and their Particles put into a swift Motion And Thirdly It is requisite that the Animal Spirits should be of an oyly Sulphureous volatile Temper that being more easily rarified and expanded they may be presently put into Motion and cause the whole Mass to ferment Having then explained the Heat of the Blood and proved it agreeable to these Circumstances I am for the Reasons before mentioned perswaded to believe that the Heat of the Blood thus proceeds from Fermentation OF THE USE OF THE LUNGS FOR as much as appears from the Books of several Learned Men the Use of the Lungs hath not been hitherto indisputable no more than the Use of other Parts For as there are several Opinions concerning others so there are no less Disputes about this whilst some would have it to be only a sort of Fan to cool and air the Blood And others that it was designed to kindle and put the Blood into a Flame by continually supplying it with Nitre Whether of these is most probable may easily be gathered by considering the Effects that Air hath upon us For since the Air is continually drawn in and thrust out again in Respiration any one that does but know what Effects it hath upon himself cannot be ignorant of the Use of the Lungs in respect of the Heat of the Blood evidently finding himself cooled by it and if any one that by daily Experience finds that it cools him can conclude thence that it kindles and promotes the Heat of the Blood he may be pleased with his Notion but no Body else will with such as contradict self-evident Truth But that it may appear how far the Lungs may be said to be a Fan or Ventilabrum to the Blood and whether the Air promotes the Heat of it or not I shall take this Method First consider the Use of the Lungs with respect to the Rational Soul and Secondly with respect to the Body The Use of the Lungs with a more immediate Respect to the Soul appears to be nothing else but as a large capacious Vessel endued with a Cavity to contain a great Quantity of Air so that it performs the same Office in the Body as a Pair of Bellows to Organs For as in Organs the Bellows supply Pipes of different sizes with Air and that being driven through them produces different Sounds so the Lungs dilated and extended by the Motion of the Thorax and being full of Air contract and accordingly as the Pharinx and it's Parts are differently modulated so the Air forcibly driven through them causes different Voices In which Action the Lungs seem chiefly to be an Organ made on purpose to be serviceable to the rational Soul to express all it's Conceptions and Reasons and to form Voices or Articulate Sounds to signifie those Notions contained in and apprehended by it that those Things which must otherwise remain in silence might be communicated to promote a mutual Commerce and Conversation amongst Men. But here some may ask if it be chiefly designed to form articulate Sounds as it really seems to be why do we take our Breath continually Or why are our Spirits constantly consumed by keeping the Part in a perpetual Motion Since sometimes we use it very little for a long time to express any Thing by one half of our Lives and the larger too being passed away in Silence To which it may be answered that it is necessary the Lungs should be in a constant and continual Motion that they might be kept in readiness to express what and whenever we have a Mind Another Reason is that since the Cavities of the Lungs are constantly supplyed with a serous Lympha to moisten their Coats and to moderate the Acrimony of the Air it is necessary there should be a constant and continual Respiration to carry that serous Lympha off which would otherwise stuff up the Bladders of the Lungs that they would be incapable of receiving Air but every Inspiration that superfluous Moisture being mixed and incorporated with the Air is by every Expiration carried off which prevents those ill Consequences which would otherwise follow Another Reason why the Lungs ought to be always in Motion is least they should Preter-naturally affect and disturb the Constitution of our Bodies when put in Motion as we have a mind to express our selves for if the Lungs were at other times quiet and still our Bodies would be put into such Disorder by violent and sudden Motions that we should be as unfit to discourse of