I shall before I proceed to shew how the Heat of the Blood is caused endeavour to demonstrate those Spirits and prove that they circulate through the Nerves as plainly as we can by the help of our Reason and the Testimony of our Senses demonstrate any and the most apparent Things whatsoever For any one that does but look into the Substance of the Brain I think needs neither doubt nor be ignorant what the Animal Spirits are nor of their Nature which appear as manifestly as the Humors of a Mans Body But perhaps it will be a hard Task to perswade some that that oily and clammy Moisture in the Brain is Animal Spirits since it seems as some say to be as gross a Substance as any Liquid in the Body To this I answer that if we take Animal Spirits or that Moisture in the Brain and compare it with coagulated Blood it is much more fine and pure and not half so tough and clammy whereas if it were a more gross and sluggish Body it would be a great deal more Viscid and Phlegmatick But if we further compare the Taste of the Brain with the Tast of the Blood it will be evident that that sweet Substance is the Spirit of the Blood and consequently that it is Animal Spirit For as the Blood is a sweet Mass inpregnated with diverse sorts of Salts and Phlegmatick crude Serum so the substance of the Brain is moistened with an oyly sweet Salino-Sulphureous Mass free from those indigested Dregs that swim along with the Blood being separated from those Impurities in the cortical Part of the Brain now if a Spirit partakes of the Nature of that Body it is separated or drawn from this is an Argument strong enough to convince any Rational Man that that Moisture is the Spirit of the Body since we learn by our Taste that it is the purest and most refined Part of the Blood as a Spirit ought to be But some think it too gross a Humour to perform all those Actions which they think the Animal Spirits do yet if they grant that the Mass of Blood is the Pabulum of the Animal Spirits as I think none can deny since any considerable Evacuation of it presently sinks and diminisheth them then it will be very manifest that those Spirits are able to perform all those Actions that we can truly suppose Animal Spirits to do for if by withdrawing that sweet Viscid Pabulum that sweet oyly Mucilaginous Moisture in the Brain be diminished and upon that Diminution the Animal Spirits are presently less vigorous and on the contrary if by enriching the Blood and consequently encreasing the stock of Animal Spirits the Actions of the Body as well as of the Mind be stronger we must consequently believe that they are moderately performed by them when that oyly Substance neither too plentifully abounds nor is too much spent and consumed But some People will not believe That to be Animal Spirit because they say they cannot get so much as one drop of it out of the Vessels To which I answer that if they deny it to be Animal Spirits because they cannot gather it in drops by the same Reason they may deny Blood to be Blood because in small capillary Veins when it is coagulated it cannot be dropped out For not only the capillary sanguiferous Vessels are so small that they cannot be seen by good Microscopes but also the Nervous Fibers are so extreamly diminutive and fine that they have been computed to be fourscore times as Fine as a Hair and consequently the Liquor contained in each must be so little that five or six Hundred Vessels must be joyned together to make one Drop so that being separated and divided into very small Portions by the Intermixture of the Vessels it is no sooner exposed to the Air but is immediately chill'd and coagulated Which we may more easily believe when we take Notice how thin and fluid the Mass of Blood is as long as it is in a swift and constant Circulation that if a capillary Vessel be but pricked with a small Pin Blood immediately spurts out yet how soon when exposed to the Air does it thicken and coagulate though it be exposed in great Quantities so that one would scarce think it fit to move through Veins so small that they cannot be discerned by the best Microscopes much rather then may the Animal Spirits whose Portions are so incomparably diminutive be forthwith chill'd and thicken'd when they immediately as soon as they are expos'd to the Air are almost equalled with Particles of Nitre But be it never so evident that these are the Animal Spirit 's that are in the Brain yet most deny them a constant and free Circulation But since we see that Blood which is much more gross and thick than Animal Spirits when coagulated as long as it is in a quick and brisk Motion can move through the smallest Capillaries we have great Reason to believe that the Animal Spirits would move much more swift when separated and preserved from the Nitre of the Air and although they immediately thicken when exposed to the Air yet are they much more thin and liquid when in Circulation But it is not only evident that these Spirits are in a continual Motion but also highly necessary For either they must be in Motion or stagnate and if they should stagnate they would in a short time corrupt and putrify Besides since there is a continual and constant Supply separated in the Cortical Parts of the Brain there must be a continual Decrease or otherwise there would be no room to receive them which Evacuation we can rationally imagin to be no other way but through the Branches of the Nerves and also because we perceive the Effects of them in the Musculous Parts From hence it appearing that that oyly Substance in the Brain is separated from the Mass of Blood being the sweetest and most spirituous Part of it and that it must needs circulate continually through the Nerves I shall now consider the Nature of it that we thence may gather more clearly the Manner of it's Operation Which presently appears if we do but consult our Taste the Taste of it being oyly sweet and mucilaginous that Substance being made up of the most volatile sulphureous and salt Particles of the Mass of Blood which are incorporated in some of the most digested and ripen'd Serum of the Blood and by that means appear in the Form of a Mucilage That these Spirits are made up of the finest Sulphureous Particles and the most volatile Salts of the Blood is apparently proved by our constant Diet for we always perceive our selves most full of Spirit after Meat that abounds with Sulphur volatile Salts and Oyls whereas all Acids Austeres c. which thicken Oyl and take of the Force of volatile Salt and Sulphur depress our Spirits and keep them too low That these Spirits are full of
A TREATISE Concerning the HEAT OF THE BLOOD And also of the USE OF THE LUNGS By RICHARD BOULTON of Brazen-Nose College in OXFORD LONDON Printed for A. and J. Churchill at the Black Swan in Pater-Noster-Row 1698. IMPRIMATUR JO. MEARE Vice-Can Oxon. Jan. 24. 1697. HUNC Librum cui Titulus A Treatise of the Heat of the Blood c. dignum Censemus quî Imprimatur Thomas Millington PRAESES Samuel Collins Edward Hulse Richard Morton Charles Goodall CENSORS Martij 5. 1697 8. TO THE Reverend Dr. JO. MEARE PRINCIPAL OF Brazen-Nose College AND VICE-CHANCELLOR OF THE University of Oxford SIR IT is not any great Opinion I have of my present Performance though there are some who would perswade me that it is not altogether despicable that makes me presume to prefix your Name before it Indeed amongst Men of Sense and Learning Truth for the most Part brings it's own Recommendation along with it and finds that Candid and ready Reception which it deserves But the Generality of Mankind will not relish any thing that bears not in the Front some great and eminent Name And for this Reason it is that I have made bold to make this Dedication Your real Worth which hath deservedly placed you in two Eminent Stations to both which you do more Honour than you receive from them And the Encouragement and Favour you shew to all Persons of Industry Vertue and good Learning under your Government soon determined me in the Choice of such a Patron though my small Share of each of the latter could merit neither of the former And here according to the usual Mode of Dedications I might easily enlarge upon so fair a Character But as it is your peculiar Delight to oblige do good with all the ease and sweetness imaginable so with as little Noise and Ostentation possible And I should sooner hope for your Pardon for this Presumption and the Faults of my Book than for such an Attempt upon your Modesty I shall therefore only add that you would be pleased to accept this as a Testimony of my Duty and Gratitude and that I shall always remain Reverend SIR Your Ever Obedient and Obliged Servant R. BOULTON To the very LEARNED AND JUDICIOUS Dr. R. ANGELL Resident in the CITY of CHESTER Learned Sir SIXTEEN Years Education in a University and a great many more improved in succesful and judicious Practice hath sufficiently qualified You for a Judge and Patron when I consider the former and withal my own Weakness I confess I have less Reason to desire the latter But sinoe it usually happens that those that are least subject to Faults are commonly candid Criticks and most ready to forgive others I am bolder to beg your Patronage yet not for it's Faults since that is below your Judgment but whatever Truth is contained in it which will scarce be deny'd by One that is so much an Encourager of Learning But perhaps I ought to make an Apology to You as well as the World for deviating from the Opinions of some Learned Men especiatly of that never too much Honoured Dr. Willis who was One of the Greatest Physitians of his and preceding Ages And truly all that I can say for my self is That as it would be below the Character of so Great a Man to write any Thing upon any other Consideration than an Improvement of Knowledg and Truth so undoubtedly he would not desire any Thing he writ should be believed except it seemed so That then which I hope will be an Apology for such an Attempt is That I have considered his Opinion with no other Design than an Endeavour after Truth and have offered nothing against his Opinion but plain and unprejudiced Reasons and though I have given Reason enough to prove he was mistaken in this Point yet I must ever have the greatest Veneration and Esteem for all such Men of unparallelled Worth and Learning and so candidly Ingenuous But whether this little BOOK may pretend to any Reason for what it offers or not I am more encouraged to ask Your Patronage it being approved by Men of noted Learning and eminently Judicious the President and Censors of the College of Physitians of which Number that your Self is not a Member no other Reason can be given but that Your own Choice of a more retired Life hath fixed you in that CITY where you are now resident to the Satisfaction and Good of those that commit themselves to your Care But Learned Sir That I may not press too much upon your Patience That Patronage which you were pleased to Give my Last when I was a Stranger to You both encourages me to hope for it now You have been pleased to take me into Your Favour and also that You 'll Pardon me for taking this Liberty since it is only designed to testify my Gratitude for those Favours You have already been pleased to Confer on Your very Humble and Obliged Servant R. BOULTON THE CONTENTS THE Introduction Page 1 Our Knowledg is very short ibid. And Imperfect p. 3 The Pursuit of Knowledg very desirable p. 4 Where most easily attained p. 5 The Heat of the Blood not obscure in respect of it's Cause p. 6 The Opinion of the Antients very Superficial p. 9 Dr. Willis's Opinion answered p. 11 But one Way by which Bodies grow hot p. 13 Fire is rarified Matter in Motion p. 16 Heat not actually in the Body that causes it p. 19 Heat only a Sensation p. 20 Heat only produced one Way proved further in Answer to Dr. Willis p. 23 An Objection answered p. 27 His comparison of the Blood 's Accension with Flame answered p. 28 Several Degrees of Heat without Flame p. 29 Nitre makes no Part of the Flame p. 32 How Nitre promotes Flame p. 33 Why a Candle in a Glass-Globe is extinguished by extracting Air. p. 36 Whether Nitre promotes the Heat of the Blood p. 39 Liquids fetter up Heat without Nitre p. 41 Blood may grow hot without a Sulphureous Pabulum p. 42 His Comparison of the Recrements of Flame and Blood answered p. 43 A Digression why Flame usually ascends p. 50 Why it sometimes descends p. 60 Diemerbroek's Opinion answered p. 62 Dr. Henshaw's Opinion answered p. 65 Of the true Reason of the Heat of the Blood p. 67 Animal Spirits Demonstrated p. 80 That they are in Motion through the Nerves p. 89 The Nature of them p. 91 The Reason of the Heat of the Blood explained p. 94 That Reason of it's Heat prov'd p. 100 By Attrition p. 103 How the Animal Spirits rarify the Blood p. 111 Why the Heat varies p. 112 How Sp. of C. C. raises the Pulse p. 116 The Reason of flushing Heats p. 120 How far the Blood and Spirits are Active and Passive p. 131 How the Heat of the Blood is continued p. 132 Some Objections answered p. 134 Why it's Heat declines p. 139 Of the Use of the Lungs p. 159 In Respect of the Soul p. 162 Why they
sulphureous oyly Matter is farther manifest by exposing the Brains of any Animal to the Air because they presently grow rancid and fetid It appearing then that the Animal Spirits are an oyly mucilaginous Substance abounding with the most volatile Salts and Sulphurs of the Blood and that they are in a continual Circulation from the Brain and spinal Marrow through the Branches of the Nerves and that being forcibly laid down in the Glands there meet with the Arterial Blood I shall next endeavour to shew how the Heat of the Blood is carried on and continued which I conceive to be after this Manner These oyly Salino-Sulphureous Spirits being violently driven through the Nerves meet with the Arterial Blood in the Glandules and these two Liquors being forcibly driven one against another the Particles of them are intimately mixed together by which means the Animal Spirits are as if it were ground and rubbed betwixt the fixed and more solid Particles of the Blood whereby they are minutely dissolv'd and being put into a swift intestin Motion they endavour powerfully to expand themselves and to fly away but being held in and reverberated by those grosser Particles their Motion is by that means inverted and that Force which if they had but Liberty would be lost in a further Expansion being inverted and driven forcibly upon the other Particles they mutually increase and promote one anothers Motion by which Motion the Blood when it affects our Sensory causes us to perceive Heat In carrying on of which it is to be observ'd that the Animal Spirits being thus accidentally expanded and put into Motion by the grosser Parts of the Blood and being thus held in and struck back by them does not only by that Means fly back and increase each others Motion but also hurry the grosser Particles of the Blood along with them and so increase their Motion and by striking against them and knoking them together break them as if it were into smaller Parts and consequently ratify and expand Them also It is further to be observed that as these Spirits are more or less in quantity so the gross Parts of the Blood grinding them together and putting them in Motion they more powerfully or less vigorously expand and moving accordingly digest and rarify the Mass of Blood to a higher or lower Degree and consequently put the Parts of it into a stronger or weaker Motion We may further take Notice also that the sharper the Particles of the Blood are so they corrode and grind the Spirits into Parts with greater Violence and consequently sharpen their Motion Again when the Mass of Blood is very full of and plentifully abounds with volatile Salts Sulphur the Particles of it are with less difficulty put into Motion by the Spirits and joyning with them encrease their Motion and on the contrary when the Mass of Blood is more dull and phlegmatic it neither so powerfully grinds the Animal Spirits nor is so easily put into Motion it self Furthermore The Animal Spirits do not only according to their different Quantities differently exagitate the Mass of Blood but also according to their different Degrees of Activity whence the more volatile and stronger the Spirits are the more conspicuous are their Effects Lastly we may take Notice that neither the Animal Spirits nor the Mass of Blood are altogether Active or Passive in producing these Effects but mutually both of them and by Turns Having premised this short Account of the Heat of the Blood without any manner of Proof to the end that we might have a more clear and entire View how it was caused without the Interruptions it would have made to prove every Paragraph as I proposed it I shall now proceed to a Proof of what I have proposed collectively for the Material Formal and Efficient Causes of it And First That the Animal Spirits and Arterial Blood are both forcibly laid down in the Glandules I have given sufficient Reasons to evince in my Treatise of Muscular Motion and have given further Proof of it here To prove then that the Heat of the Blood does proceed from that Fermentation it being necessary to explain the mechanical Motion of the Parts of those Liquors that work mutually one upon another I shall in the next Place shew that the Heat of the Blood is caused by such a mechanical Motion of Parts as I have before mentioned That the Animal Spirits then are forcibly driven against the Arterial Blood is so self evident that it needs no Proof and if so it must needs follow that the Particles of the one will be intimately mixed with the other and it is undeniably True that the Animal Spirits will by that means be ground and rubbed betwixt the Particles of the Blood which are in Motion and amongst which they are mixed and the Animal Spirits being of an oyly Salino-Sulphureous Nature will consequently be expanded and rarified and put by that means into a swifter degree of Motion is evident whether we consider the Effects that solid or liquid Substances have on one another when in Motion for Amber by a violent Attrition of it's Parts against a woollen Cloath feels hot the Sulphureous fat Effluviums being by that Attrition encreased and caused to fly out in greater Quantities It is evident also by striking of a piece of Flint against Steel that the sulphureous Particles of the Flint being as if it were disyok'd from the Embraces of the more firm and solid Particles of the Stone and being rubbed and ground betwixt them are put into a violent Motion which causes them so much to rarify and expand that whenever they affect our Sensory they cause that Sensation we call Heat which is accordingly violent as their degrees of Motion are more or less intense and so Amber by a mild Attrition is moderately warm and by a violenter more sensible Again It is observable in the turning of any large and weighty Wheel where the extraordinary Weight makes such a forcible Pressure of those Parts that lie about the Axle-tree that by strong and frequent Attritions of the Parts together the crude Sulphur which is fettered up in the Substance of the Wood is by degrees loosned and dissolved and being put into Motion is rarified and expanded which being still ground betwixt the solider Parts of the Wood it's Parts are yet put into so strong a Motion that they break and dissolve that solid Substance and by creating a Flame consume and burn it In like manner the Particles of Fire being applyed to Gunpowder by dissolving and grinding of it's Parts in Pieces and putting them into a violent Motion cause them to expand and explode But not only solid Bodies cause Heat by grinding of volatile sulphureous Particles betwixt them and so by putting them into Motion but also the Patticles of Liquids by grinding one upon another put themselves into so violent a Motion as not only to cause Heat but
inflames the Blood of those that are of a tender and open Constitution much sooner then phlegmatic and melancholly Peoples and as the former is evident in those that are subject to Fevers so the latter is not less remarkable in those of cold Constitutions for to encrease the natural Heat of their Blood when it is too much depressed it is not only necessary to take away some of those crude Humors which stuff up the Vessels and too much depress the Spirits but also by volatile and spirituous Medicins to encrease the Spirits and at the same time to exalt and spiritualize the Blood by absorbing Acids and exalting the volitile and subtile Parts to render them predominant Moreover that the Animal Spirits do not only according to their different Quantities and the different State of the Blood variously exagitate and encrease the Heat of it but also according to their different Degrees of Activity and Strength is put beyond Dispute by the different Effects that Spirit of Wine or Aqua-mirabilis hath upon us from Sack which any one that does but taste must soon acknowledg It remains in the next Place that I should shew how far the Animal Spirits are Active and how far Passive in causing these Effects as well as the Blood which evidently appears from what I have already said For when the Spirits and Blood are forcibly driven together then they seem to be mutually Active and Passive the Spirits being forced betwixt the Particles of the Blood and vice versâ but the Animal Spirits being ground and rarified betwixt the Particles of the Blood are so far Passive but being by that means expanded by a powerful expansive and elastic Motion exagitate the Mass of Blood and by that means are active so that throughout the whole Process it appears that neither of them singly are altogether Active or Passive but both mutually and by turns From what I have said it appearing how the Heat of the Blood is caused I shall in the next Place proceed to shew how it is continued which will be sufficiently evident if we do but consider that the Animal Humors are in a constant and continual Circulation for since all the Blood in a Man's Body is allowed to circulate through the Heart several times in an hour and that the Blood from thence is continually forced and dispersed through the Parts of the Body and so great a Quantity of Blood is at one Pulsation laid down in the whole Habit of the Body and ferments at the same time with the Animal Spirits there must needs be raised in the Blood a considerable Heat or in other Words the Parts of the Blood and Spirits must of necessity be put into so swift and intense a Degree of Motion as to enable them to produce an extraordinary Heat when they strike upon our Sensory The whole Mass then circulating thus through the Extremities of the Vessels there is not only a great deal of Blood fermented every Pulsation but also by a continual Succession of Pulsations the Blood being forced into a Fermentation by the expansive Motion of the Spirits is by that Means preserved in a constant and continual Heat But I know here will some Difficulties offer themselves and perhaps some may doubt whether the Blood only ferments in the Extremities of the Vessels and not in the Vessels themselves and since it is hot in the Arteries before it be laid down in the Glands as well as in the Veins after Fermentation they may think it reasonable to conclude that where-ever it ferments there it 's Fermentation is caused and because there is a great deal of Blood betwixt their Extremities and the larger Vessels they may think that the Fermentation in the Extremities cannot be the Cause of the Heat of the Blood in the larger Vessels it being an old Maxim that tolle Causam tollitur Effectus which is as much as to say the Cause immediateley goes before the Effect Another Doubt which perhaps may arise will be that since I affirm that there is such a mutual Action and Passion in the Attrition of these Humors in order to a Fermentation whether Fermentation can be carried on in such a manner in so short a Time as the quick Circulation and consequently Protrusion of the Blood from the Extremities of the Vessels admits As to the First To wit whether the Fermentation of the Blood be caused in the Extremities of the Vessels or the large ones I affirm that it is chiefly and originally caused in the Extremities of the Vessels just where the Nerves and Arteries meet and where their contents are first mixed together and that the Fermentation in the larger Vessels is but a Continuation of the Effects of the same Original Cause and as when Water is heated over a Fire that Part of the Water which is at the top of the Vessel that contains it is as truly said to receive it's Heat from the Fire as that in the Bottom so that Blood which is in the Body of the Vena Cava is as really put into a Fermentation by a Mixture of Spirits as that in the Extremities for the Animal Spirits being mixed with the Arterial Blood in the Glands and ground betwixt their Particles and being by that means put into an elastick and expansive Motion they powerfully ferment and exagitate the whole Mass This Blood then so fermented is thrust out of the Glands by a Succession of Matter forced in the next Pulsation and so forwards by the next successively till it be driven into the Vena Cava Now as soon as it is thrust out of the Glands those Spirits which did so powerfully expand before and the remaining Part of them which are not mixed with that subtile Liquor that circulates through the Fibres being yet further corroded and exagitated by Pulsation still continue to expand themselves and by that means keep the Blood in a continual Heat And the Animal Spirits being yet more expanded do not only continue but in a great Measure encrease the Heat of it But these Spirits being frequently opposed in their Expansion by striking against the Blood loose in a short time a great deal of their Vigor the Particles that before grund the Animal Spirits betwixt them obstructing their Motion and the Animal Spirits not being able any longer to keep them in a just Motion sufficient to continue the Heat which is Natural to human Blood they are as if it were linked and fettered up betwixt those grosser Parts are incorporated into one Substance with them which is the Reason that the Blood by frequent Circulations is ripened and digested and for this Reason the flesh of a Hare grows tenderer by being coursed along time The Blood being thus impregnated with Animal Spirits and by that means wanting Spirits in a free and strong Motion would by degrees grow cold but the Intervals of time while the Blood moves from the Extremities of the Vessels to
into Motion The volatile Salts and Sulphurs in the Mass of Blood make it more apt to be fermented Which is more or less promoted according to the different Degrees of the Activity of the Spirits Neither the Animal Spirits nor Arterial Blood are wholy Active or Passive That the Heat of the Blood proceeds from Fermentation proved That Heat proceeds from Attrition further proved Not only solid Bodies but also Liquids grow hot by an Attrition of their Particles The Particles of 〈◊〉 of these Humours are first put into Motion by Circulation That the Particles of refined and rarified Matter are by an Inversion of their Motion put into a higher degree of it proved How the Animal Spirits rarifie the Blood That the Animal Spirits according to their different quantities differently exagitate the Mass of Blood prov'd By the observation of People of different Ages As also by different Constitutions And the Practical Part of Physick How Spirit of Harts-horn raises the Pulse That the Spirits according to their different Degrees of Activity variously exagitate the Mass of Blood The sharper the Particles of Blood are the more they corrode the Spirits and put them into Motion The Keason of flushing heats in the Scurvy Proved by comparing the Nature of the Medicines that oppose it and correct it That as the Blood as more or less Volatile it's Parts are put more or less easily into Motion proved And that it is differently promoted according to teir different Degrees of Activity of the Spirits How far the Blood and Spirits are Active or Passive How the Heat of the Blood is continued Some Objections considered and answered The first Objection answered viz. whether the Heat of the Blood be chiefly caused in the Extremities of the Vessels The Reason why the Heat of the Blood in time decays And that Reason proved How Fermentation is carried on in a dying Body and the Reason why it ceaseth when it is quite dead Another Argument to prove that the Heat of the Blood depends on and is caused by Attrition Fermentation Circulation mutually depend on one another The second Objection answered viz. That Fermentation may be performed in so short a time as the Circulation of the Blood admits The Blood is more powerfully fermented in the substance of the Heart than in any proportionable Part of the Body besides Fermentation is not only promoted in the Muscular Parts but also in the internal Bowels Three things requisite to continue the Heat of the Blood The Vse of the Lungs in Respect of the Soul Is to express all it's Conceptions and Reasoning Why the Lungs ought to be in a continual Motion is because It carries off that Superfluous Moisture that supplies them And that their voluntary Motion might less Preternaturally affect our Bodies What Effects it causes when too thick and also why thick foggy Air is troublesom to some People The Vse of the Lungs in respect of the Body Seems to be to perform the Office of another Heart By helping the Blood to force violently enough into the Cavities to distend them against the next Contraction How stopping the Breath of an Animal kills it Why by permitting it to breath again the Circulation of the Blood is renued How the Motion of the Heart is promoted in an Infant unborn The Office of the Lungs is partly voluntary partly involuntary What Effects the Air hath upon the Mass of Blood In respect of it's Colour Nitre depresses the Heat of the Blood What effects Nitre hath upon the Serum of the Blood
except by hindring the fierce volatile Parts which ought to be dissipated from flying away through the Pores of the Skin which being increased thereby to too great a Quantity exagitate the Mass of Blood too much From hence it breifly yet plainly appears that the Nitre of the Air alters the Colour of the Blood and also serves to temper the Heat of it I shall now consider what Effects it hath upon the serous Lympha and if we may but compare it to Milk which differs only from Chyle by being less impregnated with Oyl it will be manifest that it precipitates the Watry Parts of the Serum which joyning with the fixed Salts of the Blood dispose them to be separated and carryed off by the Urinary Passages This is so strongly proved both by Non-Naturals and Medicine that to deny it would be to contradict Reason and plead Ignorance of those Things it is almost impossible for us not to take notice of for if we sit by a Fire in a close warm Room and drink a good Quantity of Beer which is not very strong it presently if we go into the cold Air runs off by Urin besides nothing in Medicine is a more known and common Diuretick than Sal. Prunel which is purified Nitre concentered and condensed and it is no less observable in an Experimental Observation of the Famous Dr. Lower's who in his Book de Corde takes notice that as much Serum is precipitated in a short time after we rise from Bed as in the whole night when we are less affected with the ambient Air. How Beneficial Nitre is in Precipitating the Serum of the Blood and what Advantages the Animal Oeconomy receives thereby I shall not now enquire yet how inconsiderable a Part of it's Office soever it may seem yet if it be duly weighed it will appear very useful From what I have said concerning the Alterations made on the Blood and it 's Serum I should now proceed to consider how they influence each other but since as much as is sufficient for our present Purpose may be gathered from what hath gone before it being plain that the cool Serum will help to temper the Heat of the Blood and vice versa I shall wave a further Notice of it here and should rather shew That The Lungs perform many more and considerable Offices in respect of each Part But to explain them would not only be to treat of the Lungs but the whole Body and the Use of all the Parts which being not my present Design I shall omit giving an imperfect Account of them because they are so interwoven mutually with one another that they cannot truly be understood without an Account of the whole FINIS Our Knowledg in Philosophy is limited to a small Part of the Creation Which is furnished with Objects too copious for our Senses Of which at the best we have but an imperfect Knowledg The Pursuit of Knowledg very desirable Especially of that which is most Advantagious There is more Reason to expect Truth and Certainty in the Microcosm than the Macrocosm Where it is easily attained The Heat of the Blood not obscure in respect of it's Cause Both Antients and Moderns have differed as to the Cause of it The Opinions of the Antients very Superficial and Insatisfactory Dr. Willis ' s Opinion considered Who asserts that there are three ways by which Liquids grow hot And that the Blood grows Hot by Accension To which it is answered that there is but one way in Philosophy by which all things grow hot Several degrees of Heat differ only in Degrees of a peculiar Power to cause Heat And Fire which is the highest is rarified Matter in a swift Motion which Masked in different Subjects affects not our Sight Heat is not actually in the Body that causes it but potentially because that Body hath a power to cause such a Sensation Heat is only a Sensation which is actually where there is Sense to perceive it That Heat is only produced one way further proved Viz. by putting the Parts of Matter into Motion A seeming Objection answered His Comparison of the Bloods Accension with Flame considered There are several degrees of Heat produced without visible Flame Nitre makes up no part of the Flame The Nitrous parts of the Air promote Flame by keeping i'ts Matter from dispersing too soon Wherefore Fire burns better in the Winter than in the Summer Why a Candle in a Glass Globe is extinguished by extracting the Air. His Comparison of extinguished Flame compared with the Death of an Animal considered Nitre does not promote the Heat of the Blood but rather depresses For in Liquids the volatile Parts are sufficiently opposed by the Parts of the Blood and kept from flying away Blood may grow hot without a Sulphureous Pabulum His Comparison of the Recrements of Flame and of Blood considered Which appears widely inconsistent First because that Juice that sweats through the Coats of the Trachea and the Skin is not Recrementitious And the Fuliginous Effluviums of Fire are Recrements Secondly because the former if not carried of encrease it But Smoak extinguishes Fire Smoak is not altogether an Effluvium of Flame Smoak thus compounded A Digression in which is given the Reason why Flame Ascends rather then Descends Which is because it hath less Opposition in it's Motion that way Because the Air the nearer to the Center makes stronger Opposition than that above Which is proved by these Experiments It is also proved by the Expansion of Gunpowder The Motion of Flame downwards is a natural Motion in Philosophy Diemerbroek's Opinion examined Dr. Henshaw ' s Opinion considered Antient and Modern Writers have rather disputed about the Vse of Words than much difference observable in their Opinions The Reason why Heat affects our Sensory does not shew how it comes by that Power The Blood grows hot by Attrition the Consequence of which is Fermentation Attrition and the consequence of it both to be signified by the Word Fermentation How far the Heat of the Blood proceeds from Pressure and Mixture To dispute about Words is not material in an Enquity after the causes of Things The whole Body is made up of Vessels and Humors contained in them By what means the Spirits and Blood are mixed in order â—o a Fermentation Animal Spirits demonstrated In the substance of the Brain Viz. that Mucilaginous oily Moisture which we call Brains An Objection Answered That it is the most spirituous Part of the Blood and consequently Animal Spirits proved That oyly Substance is capable of performing all those Actions which we can suppose the Animal Spirits do Another Objection answered That these Spirits are in a constant Motion proved The Nature of the Animal Spirits considered The Reason of the Heat of the Blood explained How it's Heat is promoted The Heat of the Blood varies according to the different Quantities of them It varies also according to the sharpness of those Humors that put the Animal Spirits