An enlarged syllabus of philosophical lectures: delivered by Hugh Smith ... With the principles on which his conjectures are founded concerning animal life, and the laws of the animal oeconomy. These principles are applied not only to the general doctrine of the glands, but likewise to some new thoughts on the nervous system, the gout, and paralytic complaints.






With the PRINCIPLES on which his CONJECTURES are founded concerning ANIMAL LIFE, and the LAWS of the ANIMAL OECONOMY.

Theſe Principles are applied not only to the general Doctrine of the Glands, but likewiſe to ſome new Thoughts on the Nervous Syſtem, the Gout, and Paralytic Complaints.

LONDON: Printed for L. Davis, Holborn; J. Robſon, New Bond-ſtreet; J. Dodſley, Pall-Mall; T. Cadell, Strand; G. Kearſly, Fleet-ſtreet; G. Robinſon, and T. Evans, Pater-noſter-row; and Meſſrs. Richardſon and Urquhart, Royal-Exchange.

Where alſo Dr. SMITH's other Publications are to be bought.


To thoſe Gentlemen in particular who honoured DR. SMITH by their obliging Condeſcenſion in attending his Lectures on the Philoſophy of Phyſic—and to the Public in general.


I SHOULD be much wanting in reſpect, much more ſo in gratitude, did I not in this addreſs acknowledge the pleaſing remembrance of that very candid reception, with which my noble and truly liberal auditors have been pleaſed to honour ſome very imperfect endeavours to eſtabliſh the firſt elements of Phyſic.

CONSCIOUS of the many inaccuracies to be diſcovered throughout the Courſe of my Lectures, I have not preſumed to ſtile them more than rude preparatory outlines; concluding there was little more to be expected than perhaps an approbation of the deſign; and for this I truſted to the known indulgence of liberal minds. In theſe expectations [Page 6] I have been agreeably deceived: — I have been moſt kindly ſupported by the favour and countenance of men diſtinguiſhed for abilities and learning: which emboldens me to hope the preſent enlargement of my Syllabus may likewiſe eſcape the cenſure of the Public.—In my Introductory Lecture I mentioned that the deſign had been many years in contemplation; but, fearful of my own want of importance, awed by the formidable appearance of the taſk, and the almoſt infurmountable difficulties attending the promulging a new doctrine, with ſuch a degree of ſucceſs as might intitle it to a fair and candid diſquiſition,—I could not before ſummon the fortitude neceſſary to appeal to the Public.

WHEN the Lectures were compiled, many doubts remained concerning the propriety of delivering the Conjectures on Animal Life; and had it not been for the perſuaſion of ſome friends, whoſe judgments I have ever reſpected, the Conjectures had been ſuppreſſed: they obſerved, and with propriety, my Lectures would be imperfect, unleſs the Principles were communicated on which my own maxims were founded.

To their determination I ſubmitted, not without reluctance, being fearful of the event; leſt I ſhould either have been deceived in my reaſonings, or might not be able to expreſs myſelf, ſo as to be clearly underſtood.

IT is even now my moſt earneſt deſire, the Principles on which the Conjectures are founded ſhould be coolly and deliberately enquired into. Many of the opinions are undoubtedly [Page 7] new and ſingular: Truth being the great object of my purſuit, I ſhould have reaſon to lament the partiality of my friends, if I ſuffered myſelf to be prevailed on to propagate errors, however plauſible they might appear: For theſe reaſons I have withſtood many reſpectable applications to deliver another Courſe of Lectures; and am determined not to repeat them, till the Public have had a fair opportunity of examining the truth of the Principles, on which thoſe Conjectures are founded, that ſupport the practical obſervations delivered in the Lectures.

IT is well known, that all learned and wiſe men ever regard new ſyſtems with a jealous eye; and their ſo doing is to be accounted a mark of wiſdom. I wiſh my principles to be received with a manly diſtruſt; ſuffer them, however, to undergo a full and candid examination. I am ſenſible it will require ſome degree of attention for gentlemen to comprehend the whole of them; eſpecially thoſe who have not ſeen the experiments, and who are unacquainted with the reaſonings by which the principles have been ſupported.

THESE difficulties may perhaps occaſion doubts in the minds of ſome medical, and other learned men; ſo far it muſt be acknowledged they will operate againſt me. I am content it ſhould be ſo. Poſſibly thoſe doubts may excite ſome more able perſons to ſearch after the truth; and, as I am not wedded to my own opinions, I ſhall moſt readily join in their condemnation, whenever they are proved to be erroneous.

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THE enlargement of my Syllabus will, I apprehend, prove acceptable to many of thoſe Gentlemen who honoured my Lectures by their preſence; ſome of them indeeed have applied to me on this ſubject. The Public at large, perhaps, may be pleaſed with having an opportunity of knowing the principles; and generous minds ever ſhew favour to an attempt, however poorly executed, that has for its objects the information and happineſs of mankind.

I SHALL beg leave to repeat what was delivered in one of my Lectures—

‘"I LOVE the profeſſion of phyſic. I honour able medical practitioners. I wiſh to convince mankind of the benefits that may be derived from a practice of phyſic founded on liberal and rational principles. I have uſed my beſt endeavours to convey clear and adequate ideas concerning animal life, and the laws of the animal oeconomy; with a full hope and firm perſuaſion, that thereby the practice of phyſic may be rendered more univerſally beneficial; and with a ſincere deſire that farther dignity may be added to the profeſſion."’

WHETHER my maxims be true or falſe, permit me to add, if I cannot, by a generous and candid behaviour on my own part, ſuppreſs the envy and jealouſy of illiberal minds,—I can pity and forgive ſuch men.

IT is my earneſt deſire to promote medical knowledge; to render the philoſophy of phyſic, an eaſy, pleaſing, and [Page 9] rational ſtudy; and to point out to gentlemen of fortune the propriety of their becoming acquainted with the firſt elements of a ſcience—founded in the knowledge of the Laws of Nature, reſpecting animal life.

I MOST ſincerely wiſh my fellow labourers, in the healing art, may with unanimity join me in this undertaking—let us endeavour to convince mankind it is their intereſt, on all occaſions, to apply to able medical practitioners—more eſpecially in that claſs of complaints termed Chronic, which is at preſent the great field of quackery.



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THE following is the Syllabus firſt publiſhed, in which no mention is made of the Conjectures to be delivered after the Lectures, concerning the firſt material cauſe of animal life, and the laws of the animal oeconomy.

IF it be aſked, why this part of the deſign was not taken notice of?—I refer my reader to the doubts already expreſſed in the Introductory Preface.—I was likewiſe fearful this attempt might be treated as altogether chimerical—and [Page 12] did not care to run the riſk of premature ridicule; well knowing that, ſometimes, where ſolid objections are not advanced, private whiſpers, and ironical buffoonery, may create inſuperable prejudices againſt a man who dares to venture out of the beaten paths of Science.


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THESE Lectures are intended to render the Practice of Phyſic a liberal ſcience; as derived from the known and eſtabliſhed laws of Natural Philoſophy—to open a new theory, adapted to practice, and correſpondent to thoſe laws.

No perſon, it is believed, on this plan, has ever yet attempted to bring the rudiments of the ſcience of Medicine, into one general and compendious point of view.

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IN the execution of the plan, poſſibly ſome practical rules may ariſe, ſupported on eſtabliſhed principles, tending to the improvement of the ſcience*. By a chain of rational and philoſophical reaſoning it is deſigned to call forth that knowledge obtained by detached ſtudies; and to apply it to the great end and purpoſe for which thoſe ſtudies were inſtituted.

MEN are often poſſeſſed of powers and talents, to which they themſelves, in ſome degree, are ſtrangers—and great abilities are often buried in oblivion, for want of right rules in practice. The truth of this obſervation many medical men have the mortification to experience; and on this account only perhaps they paſs their lives in obſcurity; and their knowledge is loſt to the world. The preſent Lectures, therefore, are particularly recommended to medical ſtudents.

To men of letters human nature is acknowledged to be an agreeable object of contemplation. Can it be leſs entertaining to any man of good natural underſtanding? The knowledge of NATURE is not ſurely above the reach of common ſenſe — Conſidered liberally, and freed from all unneceſſary terms of art, it will be found a pleaſing ſcience. Theſe Lectures, probably, may throw a new light on the ſubject; by opening to familiar view the firſt ſprings of life; the cauſes of [Page 15] man's gradual riſe; neceſſary decay; and the cauſes likewiſe of the diſeaſes to which he is liable. Is not every human being intereſted in this inquiry? How many men have been rendered miſerable by dipping into medical authors, for want of a conſiſtent view of the leading principles of the ſcience? In theſe Lectures, though on medical ſubjects, every thing myſterious being removed, man properly becomes the object of rational, or philoſophical contemplation.—It is to be hoped, likewiſe, the practice of phyſic may be rendered more univerſally beneficial, and poſſibly freſh dignity may be added to the profeſſion.


FIRST LECTURE—Introductory.—The Importance of the Deſign—not confined to men of the profeſſion—but of utility to all gentlemen of liberal education—the propriety of their becoming acquainted with the elements of the ſcience of Medicine enforced.

SECOND LECTURE—Hiſtorical,—but principally in regard to the Practice of Phyſic.—It is not only uſual, but uſeful and entertaining, to trace the origin of whatever engages our inquiry.

THIRD LECTURE—On Animal Life.—It is impoſſible to eſtabliſh the Practice of Phyſic, on liberal and rational principles, [Page 16] without clear and fixed ideas concerning Animal Life—the great deſign of the art being to aſſiſt Nature, in order to preſerve the lives of Animals.

FOURTH LECTURE—On Nutrition.—The deſign of this Lecture is to inquire into the mode of Nutrition, as it is performed in animal bodies—to point out certain facts, as data, to prove that Nutrition is univerſally carried on, in animal bodies, by the glandular ſyſtem.*

FIFTH LECTURE—The ſubject of Nutrition continued.—This doctrine, though perhaps allowed, in part, by many able practitioners, has never yet been proved in the whole—its novelty therefore might induce ſome to diſpute the truth of it, if the matter of fact reſted only on a ſingle perſon's practical diſcoveries; or on a few ſimple facts, however evident to the ſenſes.—We ſhall therefore confirm this doctrine by phyſiological reſearches, and mathematical reaſonings founded on the eſtabliſhed data contained in the Fourth Lecture.

SIXTH LECTURE—A continuation of the ſame ſubject.—No proof ought to be withheld, that can rationally be advanced, in ſupport of principles in themſelves important, but not generally eſtabliſhed.—We ſhall therefore, by mechanical [Page 17] reaſoning, farther confirm this doctrine of Nutrition being univerſally carried on by the glandular ſyſtem.

SEVENTH LECTURE—On Diſeaſes.—Here we mean to prove, agreeable to the principles before-mentioned, from practical experience, that the primary errors in animal bodies, which may juſtly be ſtyled the internal, incipient, cauſes of diſeaſes, are, univerſally, ſeated in the glandular ſyſtem.—this, if well ſupported, muſt neceſſarily eſtabliſh our doctrine concerning Nutrition beyond the poſſibility of doubt.—It muſt likewiſe be productive of new theories in many caſes; and alter the preſent mode of practice, with regard to the curative intentions, in various diſeaſes.

EIGHTH LECTURE — How a Phyſician differs from a Quack.—Having in the former Lecture eſtabliſhed fixed principles, as a ſolid foundation for a liberal and rational practice of Phyſic, the preſent philoſophic inquiry ſeems properly to take place.

NINTH LECTURE—Will ſet forth the ſuperiority of a rational Practice of Phyſic over empiriciſm and quackery.

TENTH LECTURE—Acute and Chronic Diſeaſes diſtinguiſhed.—In this Lecture we ſhall take the liberty of drawing the line of diſtinction, in ſome meaſure different from that already given by medical writers; but perhaps neceſſary to eſtabliſh the Practice of Phyſic, on liberal and rational principles—which regularly leads to—

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ELEVENTH LECTURE—An inquiry into the cauſes of Quackery.

TWELFTH AND LAST LECTURE—Contains ſome rules, that we humbly conceive will be found uſeful; eſpecially, to younger practitioners, in their conduct towards patients, both in acute and chronic diſeaſes; in order to obtain their rational confidence, and to convince them of the benefits that may be derived from a Practice of Phyſic, founded on liberal and rational principles.


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THAT no confuſion may ariſe in our ideas, and with a view to be clearly underſtood by every one into whoſe hands this Syllabus may fall, it will not be improper to ſubjoin an explanation of the word GLAND, as it is applied in the Lectures.

ALL medical writers agree in this point, that a GLAND ſerves to ſeparate a particular humour from the blood. GLANDS are diſtinguiſhed, by anatomiſts, into ſimple and compound; accurate deſcriptions have been given of many that are viſible, and new GLANDS are continually diſcovered. It concerns not our preſent purpoſe to inquire into their ſtructures: Different GLANDS are evidently appointed for different uſes—Whether, therefore, they be ſimple or compound; or whether they be any thing more than the ultimate terminations of ſingle arteries, convoluted, or not; [Page 20] every part of the animal oeconomy muſt be allowed to be a GLAND, whoſe office it is to ſeparate, percolate, or drain a particular humour from the blood; which humour, when thus ſeparated, is no longer blood.

In ſtrict conformity to Phyſiology, this Deſcription eſtabliſhes a clear and adequate idea to be conveyed by the word GLAND.


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THROUGHOUT the courſe of our Lectures, we endeavoured from effects to lead to cauſes—and thereby to account for Nutrition—and the primary cauſes of Diſeaſes.

OUR Conjectures concerning the firſt active material cauſe of Animal Life, and the laws of the Animal Oeconomy, for obvious reaſons, were totally detached from the Lectures—on theſe points, we endeavoured to trace effects from cauſes; and, by arguments founded on experimental proofs, we hope at leaſt to have ſtrengthened ſome of the opinions delivered in our Lectures; though perhaps we have not been able fully to eſtabliſh any point contended for.

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IT is neceſſary, however, to be remarked, that nothing new is meant to be advanced concerning the properties of air, nor is it intended to enter into its properties at large—the application of its properties to Animal Life, is all we aim at: Some Conjectures are offered, that ſeem to ſhew the probability of air, put into motion by heat, being not only the firſt active material cauſe of new life, but the actual ſupport of life, throughout every different ſtage of our animated exiſtence.

THESE Conjectures, if admitted, ſhew the Moſaic account of the creation of man to be philoſophically true—‘ that the Lord God formed man of the duſt of the ground, and breathed into his noſtrils the breath of life, and man became a living ſoul," (Gen. ch. ii. v. 7.) ’—and that the laws of generation are the means appointed by our Creator to preſerve this active operative cauſe of life, ſo given: For the Conjectures ſeem to evince what we term VITAL AIR, to be the firſt cauſe of motion, not only in man, but throughout the whole animated creation.

OUR leading aphoriſm runs thus—


WE maintained the truth of this aphoriſm, not only by death and its conſequences, but likewiſe by life and its effects: It ſeems alſo to be farther illuſtrated by the following Principles—from which many other important concluſions have been drawn.

Each Night, before the Lecture, a variety of Experiments were exhibited, to demonſtrate the Truth of the following Principles: many of which will not be denied by ſcientific Men; and where it ſeems neceſſary, the others are attempted to be explained.

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I. AIR is matter.

II. MATTER is of itſelf inactive, but capable of being put into motion.

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III. AIR, as matter, is capable of different arrangements, modifications, and combinations, in obedience to the general laws of matter.

IV. AIR is a fluid—but has properties peculiar to itſelf, and different from other fluids;—for,

V. AIR is an elaſtic fluid, and the force of its ſpring is proportionable to its weight.

VI. AIR poſſeſſes the property of rarefaction, or expanſion.

VII. HEAT—by which we mean a ſimilar effect to that produced by fire, will rarefy or expand air.

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VIII. AIR poſſeſſes the property of compreſſion, or condenſation.

IX. EXTERNAL preſſure will condenſe, or compreſs air.

X. COLD will condenſe, or compreſs air.

XI. AIR then is rarefied by heat, and compreſſed by cold.

XII. AIR exiſts in all bodies, fluid and ſolid.

This, perhaps, will not be doubted by ſuch as are acquainted with experiments on air—for the ſatisfaction of others, the truth of the Principle was proved by experiments on gold, ſilver, copper, braſs, lead, marble, various other ſtones, wood, &c. Air viſibly iſſued from them all; more from ſome, than from others, in proportion to their poroſity—the poroſity of [Page 26] wood, ſtone and metals, by help of a microſcope, may be curiouſly diſplayed to the eye.

XIII. WHEN bodies are deprived of internal heat and motion, the air contained within them may be ſaid to be at a ſtate of reſt; it being then only ſubject to the variations of the atmoſphere.

This may be proved by the Thermometer. The following curious experiment farther illuſtrates the matter of fact, and may lead to other diſcoveries: Let the bulb of a Thermometer be put into two ounces of cold water; the air, apparently at reſt in the quickſilver, by the effect of cold being more compreſſed, the mercury will quickly deſcend ſeveral degrees; when the quickſilver is again apparently at reſt, let thirty drops of oil of vitriol be put into the water; this produces heat, and the air contained in the quickſilver will as quickly be expanded; by the effect of this internal heat communicated to the fluid, the quickſilver will riſe two or three degrees: Let a little chalk be now added to the fluid, the internal heat will be farther increaſed, and the quickſilver will aſcend two or three degrees more. — Does not this experiment likewiſe ſhew that heat accompanies internal motion in fluids? — This obſervation, perhaps, may not prove unworthy the attention of ſuch Gentlemen as entertain themſelves with experiments on what is termed fixed air.

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XIV. ON the application of heat to a fluid, the firſt evident ſign of internal motion is an air-bubble.

This is experimentally ſhewn, by putting any tranſparent liquor into a ſpoon, and placing it over a candle, or a lamp; in different fluids, different appearances may be obſerved, not unworthy the attention of the curious.

XV. IN this ſtate of the fluid the air contained in it is more rarefied, and expanded, than in the cold ſtate of the fluid.

XVI. THE air contained in moſt fluids becomes ſo far rarefied as to be put into motion by a degree of heat below that of the blood; we may then fairly conclude, from the degree of heat accompanying animal life, that the air contained in the fluids of an animal body is continually in motion.

This was confirmed by a variety of experiments (oleaginous fluids excepted) by placing the fluids over a lamp, and regulating the heat by a Thermometer.

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XVII. THE tunic, or coat of every diſtinct air-bubble, is evidently formed of the ſurrounding fluid.

XVIII. EACH diſtinct bubble of air has a diſtinct and ſeparate motion.

XIX. IN different fluids, different degrees of heat are required to render theſe air-bubbles viſibly active.

XX. IN the more thin and tranſparent fluids, air-bubbles are ſooner viſible; and the air becomes fugitive below the degree of blood heat.

Water acidulated with ſpirit of vitriol, or diſtilled vinegar, becomes more tranſparent, and will prove the truth of this Principle; it may likewiſe be ſhewn by many of the white wines, and other fluids.

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XXI. THESE bubbles of air, being ſpecifically lighter than the ſurrounding fluid, naturally tend to the ſurface; and there, ſoon burſting, this rarefied air eſcapes, and mixes with the common atmoſphere, unleſs it be prevented by proper recipients.

Since the preſſure of the atmoſphere is the ſame on all fluids, how happens it that in ſome the air-bubbles are longer detained than in others?

XXII. DIFFERENT fluids poſſeſs different degrees of tenacity or coheſion: this tenacity is weaker in thin tranſparent fluids.—Air-bubbles, therefore, become ſooner fugitive in ſuch fluids.

XXIII. GLUE, gum, or ſugar, ſuſpended in fluids, render them more tenacious, or coheſive.—AIR-BUBBLES THEREFORE ARE LONGER RESTRAINED FROM BECOMING FUGITIVE IN SUCH FLUIDS.

If our conjectures prove right, this obſervation may afford a clew to examine into the laws of life in the vegetable kingdom.—This idea is thrown out for the conſideration of ingenious men; the ſubject itſelf, at preſent, not being within our ſphere.

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XXIV. EXTERNAL heat being removed from a fluid, although the preſſure of the cold atmoſphere be freely admitted; it is, nevertheleſs, a conſiderable time before the air, rarefied by heat, returns to a ſtate of reſt.

The truth of this principle may be illuſtrated by a ſpoon, in the manner before mentioned; (Principle XIV.) and it is worthy attention.

XXV. EARTHY particles may be ſuſpended in a tranſparent fluid.

The proceſs for making magneſia alba proves this—it is no contemptible experiment, though in familiar practice.

Two tranſparent liquors being mixed, they inſtantly loſe both their tranſparency and fluidity, and become one intire white inſpiſſated ſubſtance—this being repeatedly waſhed with water, the white earth, when dried, is the common magneſia alba of the ſhops.

It is well known this white earth was originally ſuſpended in an aqueous menſtruum, by means of the vitriolic acid; and in this proceſs, it is precipitated by the fixed alkaline.

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XXVI. EARTHY particles may float in air.

If any one doubts the truth of this, let him admit a ray of light into a darkened room, and he will be convinced of the matter of fact.

XXVII. AIR does exiſt in the circulating fluids of an animal.

This was proved by the blood veſſel of a bullock, being ſecured by ligatures, before it was ſeparated from the body of the living animal—it was farther confirmed by live crayfiſh, tench, &c.

XXVIII. AIR does exiſt in the medullary ſubſtance of the brain.

This is one of the moſt beautiful experiments that can be exhibited by the air-pump—if it be well ſhewn, the reſiſtance of the medullary and cortical ſubſtance of the brain is ſo great, as to produce a kind of perpetual motion.

XXIX. AIR-BUBBLES, though ſpecifically lighter than the ſurrounding fluid, cannot eſcape till the reſiſtance ariſing from the coheſion of the parts of the ſurrounding fluid itſelf be overcome.

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XXX. THIS reſiſtance, ariſing from the coheſion of the parts of the fluid, is proportioned to the different degrees of tenacity proper to different fluids; as before ſhewn.

XXXI. THIS coheſive property in fluids, then, is the bond that reſtrains the air from becoming fugitive; or, in other words, it is the bond of union.

XXXII. ANIMAL jelly, or gluten, expoſed to the common atmoſphere, and ſurrounding a globule of air, is ſufficiently coheſive to prevent this moving air eſcaping in a degree of heat ſomewhat ſuperior to that of blood heat.

XXXIII. IT being highly neceſſary to fix ſome ſtandard to regulate our inquiries—Air rarefied, in motion, detained in animal bodies by glandular ſecretions, or circulating with the fluids in the vaſcular ſyſtem, permit us to call VITAL AIR.

XXXIV. VITAL Air, Heat, and Motion, then, appear to be inſeparable, in animal life.

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ON theſe principles our arguments are founded, concerning the firſt active material cauſe of animal life; and from theſe principles our conjectures are drawn, concerning the laws of generation, and thoſe of the animal oeconomy. For the ſatisfaction of the learned, and curious, it will not be improper to add a few words concerning VITAL AIR, which we preſume to be the firſt material cauſe of motion in animal life.

THIS conjecture we have endeavoured to ſupport by arguments drawn from experiments; all tending to ſhew the rational probability of air exiſting in an active and circulating ſtate in animal bodies.

IT will be remembered, we proved air did actually exiſt in the blood of a living animal; and likewiſe in the medullary ſubſtance of the brain. We alſo proved, that in the degree of heat proper to animal life, this air muſt be in a rarefied and active ſtate; and we farther endeavoured to ſhew, by arguments drawn from an incubated egg, and other points, the rational probability, that the propelling force of air, thus rarefied, and confined in a vaſcular ſyſtem, was the firſt material cauſe of the circulation of the blood, and other fluids, in an animal body.

THE reaction of the vaſcular ſyſtem we preſume to be the ſecondary cauſe, in conjunction with the former, producing what is termed involuntary muſcular motion—this motion, in the beginning of new life, is firſt diſcoverable at the punctum ſaliens, or leaping point; which afterwards becomes the heart of the foetus. The heart we have preſumed to ſtile [Page 34] the centre of motion; by which the circulation of the blood is regulated and maintained. The blood we conſider to be a paſſive fluid, the common menſtruum from whence nutrition is derived, by means of the glands.—We preſume that ſome one order or more of the glands muſt be injured, debilitated, or totally obſtructed, before the blood of an animal becomes impure.

BY the propelling force of VITAL AIR we preſume all glandular ſecretions to be performed, and the lymphatic circulations to be ſupported by the ſame power—and by means of the glands we preſume the laws of generation to be maintained.

IN the beginning of new life, the motion of Vital Air ſeems to be ſupported by the natural heat of the parent, or by ſome adequate external means—this appears to be a general law, throughout nature, till involuntary muſcular motion becomes ſufficiently powerful to communicate that degree of internal heat, peculiarly proper to Vital Air: When this period arrives, the act of incubation ceaſes, with all oviparous animals; the foetus opening to itſelf a paſſage in order to breathe the common atmoſphere; and, in viviparous animals, the natural birth takes place, by the united efforts of the parent and foetus.

IT may perhaps be expected that ſomething ſhould be ſaid concerning the brain and nervous ſyſtem.—In this ſummary way I cannot hope to perſuade ſcientific men to think with me—however, by mentioning the points contended for, [Page 35] poſſibly objections will be ſtarted, that eventually may lead to the diſcovery of truth.

WE took notice in ſome of our conjectures, that man having a material body, it was but reaſonable to conclude it ſhould anſwer the various purpoſes for which it was ſo curiouſly formed; and that every diſtinct member ſhould have its deſtined office. We endeavoured to prove that, in the buſineſs of motion and ſenſation, the nerves, proceeding from the brain and ſpinal marrow, though the chief, were not the only inſtruments; and from numerous experimental proofs, we concluded that the reaction of the vaſcular ſyſtem, voluntary motion, and the exerciſe of the external ſenſes, could not be ſupported without the aid of the nervous ſyſtem.

IT will be recollected we uſed many arguments to ſhew the proper ſenſe of feeling ſeemed to ariſe from the due reſiſtance of the medullary ſubſtance of the brain, or nervous matter, oppoſed to the propelling force of Vital Air.

WE took occaſion to obſerve, that all the other ſenſes were obedient to the proper ſenſe of feeling; and endeavoured to ſhew that hearing, ſeeing, ſmelling, and taſting, were nothing more than the effects ariſing from feeling, which we conſidered as their primary cauſe.

As we have, under certain limitations, acknowledged the nervous ſyſtem to be the ſeat of feeling, we inquired into the effects produced by any conſiderable variation in the [Page 36] Vital Air, peculiarly exiſting in the nervous matter—and having before ſhewn the rational probability of pain ariſing from the propelling force of too highly rarefied air, we ſeemed to be warranted in drawing the following concluſions:—The ſenſe of feeling is ſeated in the nervous ſyſtem—the ſenſe of feeling becoming too exquiſite produces pain—the nervous ſyſtem is then the ſeat of pain.—Gouty ſymptoms, therefore, whether fixed or wandering, being ever accompanied with that too exquiſite degree of ſenſibility, that either produces unhappy ſenſations, or acute pain, we preſume the nervous ſyſtem to be principally affected in gouty patients.

WE endeavoured to ſtrengthen, and ſupport our conjectures concerning gouty, and what are termed nervous complaints, not only from practical experience; but likewiſe by ſhewing that a partial, or total loſs of motion and feeling, in paralytic complaints and nervous apoplexies, probably ariſes from an oppoſite cauſe—namely, from the propelling force of Vital Air exiſting in the nervous matter, or in the medullary ſubſtance of the brain, being too much abated; or from its becoming a body at reſt.

THESE are ſome of the practical inferences, ariſing from our conjectures, concerning the brain and nervous ſyſtem: happy ſhall I think myſelf if they prove any way inſtrumental towards alleviating the diſtreſſes of mankind.

WITH regard to the ſentient principle, or ſpirit of man, we obſerved, that although ſimple ideas might be ſtirred up [Page 37] in the mind by the mediation of the nervous ſyſtem; yet, our ideas are not matter: ſomething more than a material ſyſtem, therefore, ſeems neceſſary and requiſite to thinking. And if VITAL AIR be the firſt material cauſe of motion, the vaſcular ſyſtem can be conſidered only as the ſecondary cauſe:—Is it not highly improbable, then, that the ſentient principle ſhould depend on this ſecondary cauſe, namely, on a ſyſtem of organized matter?—Be this as it may, it is out of my province to enter into metaphyſical controverſies; and, as obſerved in my Lectures, I am unequal to the taſk: However, that the ſentient principle is not material, we verily believe, and endeavoured to confirm by many other arguments;—and if the mind be not material, experimental reſearches after this immaterial principle muſt ever prove in vain.

WE ventured to add, that if there be a connection between groſs material, and immaterial ſubſtances, it is probably effected by ſome rare medium; and therefore, that this union was not unlikely to be formed by means of VITAL AIR. Whether our general arguments on this point were forcible or not, muſt be left to the determination of others; we however concluded this ſubject in the following manner.

WE have endeavoured to ſhew that life depends on VITAL AIR; and that not only motion, but all the external ſenſes depend on it likewiſe—and if ſo, it ſeems a fair concluſion, that the nervous fluid, or animal ſpirits, is nothing more than VITAL AIR.

[Page 38]

I AM compelled, from my practical experience in the gout, in paralytic complaints, and other errors in the nervous ſyſtem, to believe this—and from what has been advanced, am I not authoriſed to conclude, the Moſaic accounts of the creation of man, and of the laws of generation, are philoſophically true?

HAVING thus ſet forth what may probably be deemed ſufficient to enable medical and other ſcientific men to judge of the rationality of our ſyſtem—I leave it to their conſideration, whether we mean to captivate the credulous, or to appeal to men of ſenſe in purſuit of truth.

SUCH gentlemen as have honoured me by their attention, will be enabled, from theſe outlines, to recall many of our conjectures concerning animal life, and the laws of the animal oeconomy; which, I flatter myſelf, will afford them ſome degree of ſatisfaction.

I DO not expect this ſyſtem, even if it ſhould prove to be true, to be eſtabliſhed without oppoſition; I am prepared to receive all objections that may be advanced, whether it be in my power to anſwer them or not—I am prepared to receive them, let me repeat, becauſe I wiſh the principles to paſs through the ſtricteſt ſcrutiny.

IF the principles be admitted, it is preſumed the rationality of the conjectures, on animal life, will add no little degree of weight to the doctrines contended for in the courſe of our Lectures; namely, that nutrition is carried on by means of [Page 39] the glandular ſyſtem; and that the internal, incipient cauſes of diſeaſes are univerſally ſeated in the glands.

IT is proper, however, to obſerve, whether the principles be admitted, and our conjectures allowed, or not; it does not follow, that our practical inferences, reſpecting diſeaſes, originally drawn from matters of fact evident to the ſenſes, are to be conſidered as altogether erroneous.—All that I aſk, is, to be judged with candour; and moſt chearfully ſubmit to the determination of intelligent men.

I AM fully perſuaded, thoſe gentlemen who did me the honour of attending my Lectures, will not heſitate to ſay, that my opinions were delivered with diffidence; it was my earneſt deſire to perſuade; but well knowing the ſcanty limits of human underſtanding, I believe no man can challenge me with having advanced any one conjecture as a poſitive aſſertion: Yet, this I did ſay, at the concluſion of my Lectures—

‘"As a duty incumbent on me, I have, in this public manner, communicated my thoughts to liberal and learned men; that the world at large, however they may differ in opinion, might not charge me with having reſerved my principles as SECRETS: But having entered into ſo very wide a field, I am certain, you, gentlemen, would not wiſh me too haſtily to commit to the preſs, the preſent crude and imperfect ideas, on ſubjects of ſuch importance.—If the principles on which our opinions are founded, can be fairly overturned, by arguments drawn from experiments— [Page 40] let them fall.—If not, I truſt more able advocates than myſelf will not be wanting, to ſupport the truth of our doctrines; and to enlarge the bounds of our knowledge, with regard to the theory, and cure of diſeaſes."’


Erratum: p. 35, l. 13, read ſenſes.

Publiſhed by the ſame AUTHOR.

  • I. A TREATISE on the Uſe, and Abuſe, of MINERAL WATERS; with Rules neceſſary to be obſerved by Invalids, who viſit the Chalybeate Springs of the Old or New TUNBRIDGE WELLS: The Diſeaſes likewiſe are pointed out, in which theſe Waters may prove ſalutary. Price Six-pence.
  • II. LETTERS TO MARRIED WOMEN on the Management of Infants; recommending an eaſy Method of bringing up Children, agreeable to NATURE, and confirmed by Practical Experience: The peculiar Advantages of a Milk Diet are ſet forth, with a View to prevent the Diſeaſes Infants are liable to; which generally ariſe from improper Food. Price bound Three Shillings and Six-pence.
  • III. THE FAMILY PHYSICIAN; being a Companion to Dr. SMITH'S Family Medicine Cheſt; for the Uſe of remote Country-Houſes, where Medical Aſſiſtance is not eaſily to be obtained; and for the Benefit of the Country Poor. Price One Shilling and Six-pence, or Two Shillings in Boards.
This alludes to matters of fact evident to the ſenſes ſet forth in the Fourth Lecture—ON NUTRITION.
The reader may now perceive this paſſage alludes to the Conjectures on Animal Life.
For an explanation of the word Gland, ſee page 19.
I do not wiſh to be underſtood, nor do I mean, ſtrict mathematical demonſtration, for that can admit of no doubt; but a cloſe method of reaſoning, in imitation of that uſed by mathematicians; which, in ſubjects not ſtrictly mathematical, never amounts to more than the higheſt degree of probability.