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.[Page 14]
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.
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.
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—[Page 18]
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.
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.
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.[Page 22]
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.
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.
1.3.1. PRINCIPLES ON WHICH THE CONJECTURES ARE FOUNDED.
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.
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.
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.[Page 27]
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.
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.[Page 28]
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.[Page 29]
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.
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.[Page 30]
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.
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.[Page 31]
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.[Page 32]
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.[Page 33]
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.
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."’