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“Signa tene cædis: pullosque et luctibus aptos

Semper habe feætus, gemina monumenta cruoris.”

Ovid. Metamorph. Lib. iv. 160.

Sir William Drummond, the learned apologist of Egyptian science, conceives that the laws of latent heat were even known to the philosophers of that ancient nation, and that caloric in such a state, was symbolically represented by Vulcan, while free or sensible caloric was as clearly described in the character of Vesta. Those who maintain the antiquity of chemistry, and suppose that the fabulous conceptions of the ancients were but a mysterious veil ingeniously thrown by philosophy between nature and the lower order of people, consider that the alchemical secret is metaphorically concealed in the fable of the Golden Fleece of the Argonauts, and reject the more probable solution of this story by Strabo, who says that the Iberians, near neighbours of the Colchians, used to receive the gold, brought down from the high lands by the torrents, into sieves and sheep skins, and that from thence arose the fable of the golden fleece. Dionysius, of Mytilene, offers a different explanation of the fable, and supposes it to allude to a book written on skins, and containing an account of the process of making gold according to the art of alchemy.

Notwithstanding the confidence with which modern philosophers have claimed the discovery, the experimental mode of investigation was undoubtedly known and pursued by the ancients, who appear, says Mr. Leslie,^[95] to have concealed their notions respecting it, under the veil of allegory. Proteus signified the mutable and changing forms of material objects, and the inquisitive philosopher was counselled by the Poets^[96] to watch their slippery demon when slumbering on the shore, to bind him, and compel the reluctant captive to reveal his secrets. This, adds Mr. Leslie, gives a lively picture of the cautious, but intrepid advances of the skilful experimenter;—he tries to press nature into a corner,—he endeavours to separate the different principles of action,—he seeks to concentrate the predominant agent, and labours to exclude, as much as possible, every disturbing influence.

But with whatever ingenuity and success the antiquity of chemical knowledge may be advocated, as it relates to the various arts of life, yet it must be allowed that not the most remote trace of its application to physic can be discovered in the medical writers of Greece or Rome. The operation of distillation^[97] is not even mentioned by Hippocrates or Galen; and the waters of different plants, as described by some later authors, are to be understood, as we are informed by Gesner, merely as simple decoctions, and not as the products of any chemical process; while the Essences of Dioscorides, Galen, Oribasius, and others, were only the extracts produced by the evaporation of such infusions.

Upon the downfall of the Roman Empire, all the sciences, the arts, and literature, were overwhelmed in the general wreck, and the early Mahometans, in the first paroxysms of their fanaticism, endeavoured to destroy every record of the former progress of the human mind; consigning to destruction, by the conflagration of the Alexandrian library, no less than seven hundred thousand volumes, which comprised the most valuable works of science and literature.^[98] It is not a little extraordinary that this same people were destined at a more advanced period, to rekindle the light of letters,^[99] which they had taken such pains to extinguish, and to become the inventors and cultivators of a new science, boundless in its views, and inexhaustible in its applications. The medical profession too was more particularly selected as an object of reward and encouragement; and we may say, with much truth, that our Materia Medica is more indebted to the zeal and industry of the Arabians, than to the learning of the Greeks, or to the refinement of the Romans. From this source we have acquired the milder purges of Manna, Cassia, Senna, Rhubarb, and many plants and oriental aromatics, amongst, which we may notice Musk, Nutmeg, Mace, and Cloves; the introduction of which into medicine was greatly facilitated by the situation of Bagdat, and its connection with India; and although Archigenes and Aretæus had long before applied Blisters, yet it is to the Arabian physicians that we are indebted for a practical acquaintance with their value, for in general, the Greeks and Romans prescribed acrid Sinapisms for such a purpose. We are also indebted to the Arabians for our knowledge respecting Camphor, as its name imports, for the original word was Cafur or Canfur.^[100] They are also the first upon record, who speak of sugar, and sugar-candy, extracted from the sugar-cane, which they call honey of cane; and they ushered into practice Syrups, Juleps, and Conserves. At the same time, it is but just to allow, that from the disgusting ostentation of this people, and their strong attachment to the marvellous, many absurd medicines have been introduced. Gold, Silver, Bezoars, and precious stones were received into their materia medica, and surprising virtues were attributed to them. Amongst a people thus disposed to magnificence, and from the very spirit of their religion credulous and romantic, it is not a matter of surprise that their first researches into the nature of bodies should have raised a hope, and excited a belief, that the baser metals might be converted into gold.

They conceived that gold was the metallic element, in a state of perfect purity, and that all the other metals differed from it in proportion only to the extent of their individual contamination, and hence the origin of the epithet base, as applied to such metals; this hypothesis explains the origin of alchemy; but, in every history, we are informed that the earlier alchemists expected, by the same means that they hoped to convert the baser metals into gold, to produce a universal remedy, calculated to prolong indefinitely the span of human existence.

It is difficult to imagine what connection could exist in their ideas between the “Philosopher’s Stone,” which was to transmute metals, and a remedy which could arrest the progress of bodily infirmity: upon searching into the writings of these times, it clearly appears that this conceit originated with the alchemists from the application of false analogies, and that the error was subsequently diffused and exaggerated by a misconstruction of alchemical metaphors.^[101]

An example of reasoning by false analogy is presented to us by Paracelsus, in his work de vita longa, wherein, speaking of anatomy, he exclaims: “Sicut antimonium finit aurum, sic, eadem ratione et forma, corpus humanum purum reddit.”

The processes of alchemy were always veiled in the most enigmatic and obscure language; the earliest alchemist whose name has reached posterity, is Geber, an Arabian prince of the seventh century, whose language was so proverbially obscure, that Dr. Johnson supposes the word gibberish or geberish to have been derived from this circumstance; sometimes the processes of alchemy were expressed by a figurative and metaphorical style of description; thus Geber exclaims, “Bring me the six lepers that I may cleanse them;” by which he implied the conversion of the six metals,^[102] the only ones then known, into gold. From the works of later alchemists it also appears that they constantly represented gold as a sound, healthy, and durable man, the imperfect metals as diseased men, and the means or processes by which the latter were to be transmuted into the former, they designated by the name of medicines; and hence, those who were anxious to dive into the secrets of these magicians, or Adepts, as they termed themselves, without possessing a key to their language, supposed that these descriptions were to be understood in a literal sense, and that the imperfect metals might be changed into gold, and the bodies of sick persons into healthy ones, by one and the same chemical preparation.

The hieroglyphical style of writing adopted by the earlier alchemists, was in a great degree supported by the prevailing idea that the elements were under the dominion of spiritual beings, who might be submitted to human power; and Sir Humphry Davy has observed that the notions of fairies, and of genii, which have been depicted with so much vividness of fancy and liveliness of description in The Thousand and One Nights, seem to have been connected with the pursuit of the science of transmutation, and the production of the elixir of life. That the Arabian Nights’ Entertainment admits of a mystic interpretation, is an opinion which I have long entertained. How strikingly is the effect of fermented spirit, in banishing the pressure of the melancholy which occurs in solitude, depicted in the story of Sinbad when he encountered the withered and decrepid hag, on the uninhabited island—but, to return from this digression to the subject of medical chemistry.

It was not in fact until several years had elapsed in the delusive researches of alchemy, that the application of chemical knowledge became instrumental in the advancement of the medical art. Rhases and Avicenna, who were the celebrated physicians of the age, are the first who introduced pharmaceutical preparations into their works, or made any improvement in the mode of conducting pharmaceutical processes. Avicenna describes, particularly, the method of conducting Distillation; he mentions also, for the first time, the three Mineral Acids, and distinguishes between the vegetable and mineral Alkalies; he speaks likewise of the Distilled Water of Roses, of Sublimed Arsenic, and of Corrosive Sublimate.

In the year 1226, Roger Bacon, a native of Ilchester in Somersetshire, and a Franciscan monk of Westminster Abbey, laid the foundations of chemical science in Europe; his discoveries were so extraordinary that he was excommunicated by the Pope, and imprisoned ten years for supposed dealings with the devil; it appears that he was a believer in an universal Elixir, for he proposed one to Pope Clement the Tenth, which he extolled highly, as the invention of Petro de Maharncourt.

This wonderful man was succeeded at the end of the same century by Arnoldus de Villa Nova, a Frenchman, or as others assert, a Spaniard, who deserves to be noticed on this occasion, as being the first to recommend the distilled spirit of wine, impregnated with certain herbs, as a valuable remedy; from which we may date the introduction of Tinctures into medical practice; for, although Thaddæus, a Florentine, who died in 1270, at the age of eighty, bestows great commendation upon the virtues of Spirit of Wine, yet he never used it as a solvent for active vegetable matter.

It was not however until the end of the thirteenth century, that Chemistry can be said to have added any considerable power to the arm of Physic.

Basil Valentine, a German Benedictine monk, led the way to the internal administration of metallic medicine, by a variety of experiments on the nature of Antimony, and in his “Currus Triumphalis Antimonii,” a work written in high Dutch, he has described a number of the combinations of that metal. If however we may credit a vague tradition, he was extremely unfortunate in his first experiments upon his brother monks, all of whom he injured if not killed; those who have keen ears for etymological sounds will instantly recognise, in this circumstance, the origin of the word Antimony,—ἁντί Μονοχους.

It appears that the ancients were ignorant of the internal use and administration of the metals, with the exception of iron, although they frequently used them in external applications. Hippocrates recommends Lead in several parts of his works, as an epulotic application, and for other external purposes. Litharge of Gold and Cerusse also entered the composition of several powders extolled by that ancient physician as possessing great efficacy in defluxions of the eyes. Oribasius and Ætius added “Lithargyrium” to several plaisters, and the composition of the “Snow-like plaister,” from Minium, was long preserved amongst their most valuable secrets. Whether antimony is the Stimmi or Stibium of the ancients has been a matter of conjecture; for Pliny, in speaking of its preparation observes, “Ante omnia urendi modus necessarius, ne Plumbum fiat.” This plumbum however was evidently the revived metal of Antimony, with which the ancients were unacquainted, and therefore mistook it for Lead; besides, the word Plumbum, like many others which I have before mentioned, was used as a general term; thus, according to Pliny, Tin was called Plumbum album; and Agricola calls Lead Plumbum nigrum.^[103]

The question however is unimportant, for this Stibium was never used but as an external Astringent, especially for the purpose of contracting the eye-lids, and thereby of making the eyes appear very large, which has been considered from the most remote antiquity, as a feature of great beauty; thus the epithet βοῶπὶς is constantly applied by Homer to Juno. This practice appears also to have been followed by the Jews, for Jezebel is said to have painted her eye-brows to make the eyes appear big;^[104] the expression also shews that the drug employed was the Stimmi. Εστὶμμὶσατο τους οφθαλμους ἁυτης.

To Basil Valentine we are moreover indebted for the discovery of the Volatile Alkali, and of its preparation from Sal Ammoniac; he also first used mineral acids as solvents, and noticed the production of Ether from Alcohol; he seems also to have understood the virtues of sulphate of iron, for he says, when internally administered, it is tonic and comforting to a weak stomach, and that externally applied, it is astringent and styptic: he moreover recommended a fixed alkali made from vine twigs cut in the beginning of March, for the cure of gout and gravel.

In the year 1493, was born near Zurich in Switzerland, Paracelsus, or as he termed himself, Philippus, Theophrastus, Bombastus, Paracelsus de Hohenheim, a man who was destined to produce a greater revolution in the Materia Medica, and a greater change in medical opinions and practice, than any person who had appeared since the days of Galen. He travelled all over the Continent of Europe to obtain knowledge in Chemistry and Physic, and was a great admirer of Basil Valentine, declaring that Antimony was not to be equalled for medicinal virtue, by any other substance in nature: this opinion however does not deserve our respect, for it was not founded upon observation and experiment, but on a fanciful analogy, derived from a property which this metal possesses of refining gold, as I have before related. He also used Mercury without reserve, and appears to have been the first who ventured to administer it internally,^[105] for although Avicenna asserts that it was not so poisonous as the ancients had imagined, yet he does not attribute to it any virtues; he merely says, “Argentum quidem vivum, plurimi qui bibunt, non læduntur eo.” Its effects, when applied externally, were well known to Theodoric the friar, afterwards Bishop of Cervia, in the twelfth century, who describes the salivation which mercurial frictions will produce. Paracelsus, moreover, employed Lead internally in fevers,—“Saturnus purgat febres” was one of his most favourite maxims. He also gives us directions for the preparation of Red Precipitate with Mercury and Aqua fortis.

Paracelsus, thus armed with opium, mercury, and antimony, remedies of no trifling importance, travelled in all directions and performed many extraordinary cures, amongst which was that of the famous printer Frobenius of Basil, a circumstance which immediately brought him acquainted with Erasmus,^[106] and made him known to the magistracy of Basil, who elected him professor of chemistry in the year 1527, which was the first professorship that was established in Europe for the promotion and dissemination of chemical science. But notwithstanding this testimony of his success, if we may credit Libavius, he often, like our modern quacks, left his patients more diseased than he found them; and it is acknowledged by his own disciple Oporinus, that when he was sent for to any town, for the purpose of administering his remedies, he was rarely suffered to protract his visit, on account of the general resentment of the inhabitants.

While seated in his chair, he burnt with great solemnity the writings of Galen and Avicenna, and declared to his audience that if God would not impart the secrets of physic, it was not only allowable but even justifiable to consult the devil. His cotemporary physicians he treated with the most sottish vanity and illiberal insolence; in the preface to his work entitled “Paragranum,” he tells them “that the very down of his bald pate had more knowledge than all their writers, the buckles of his shoes more learning than Galen and Avicenna, and his beard more experience than all their Universities.” With such a temper it could not be supposed that he would long retain his chair, in fact he quitted it in consequence of a quarrel with the magistrates, after which he continued to ramble about the country, generally intoxicated, and seldom changing his clothes, or even going to bed; and although he boasted of possessing a Panacea which was capable of curing all diseases in an instant, and even of prolonging life to an indefinite length, yet this drunkard and prince of empirics died after a few hours illness, in the forty-eighth year of his age, at Salzburg in Bavaria, with a bottle of his immortal Catholicon in his pocket.

In contemplating the career of this extraordinary man, it is difficult to say whether disgust or astonishment is the most predominant feeling; his insolence and unparalleled conceit, his insincerity, and brutal singularities, and his habits of immorality and debauchery, are beyond all censure; whilst the important services he has rendered mankind, by opposing the bigotry of the schools and introducing powerful remedies into practice, cannot be recorded without feelings of gratitude and respect: but in whatever estimation Paracelsus may be held, there can be no doubt but that his fame produced a very considerable influence on the character of the age, by exciting the envy of some, the emulation of others, and the industry of all.^[107]

About a century after Paracelsus, Van Helmont took the lead in physic; he was a man of most indefatigable industry, and spent fifty years in torturing by every chemical experiment he could devise, the various objects in the animal, vegetable, and mineral kingdoms. He was the first physician who applied alum in uterine hemorrhage, and he acquired a great reputation from the success of the practice.

Sylvius de la Boe, and Otho Tachenius, followed in the track of Van Helmont.

A prejudice in favour of chemical remedies having been thus introduced, the merited success which attended their operation, and the zeal and perseverance which distinguished the votaries of that science, soon kindled a more general enthusiasm in its favour. It is impossible to reduce into miniature the historical features of these chemical times, so as to bring them within the compass of a lecture: I must therefore rest satisfied with delineating a few of the more prominent outlines. The Galenists, who were in possession of the schools, and whose reasonings were fettered by the strongest predilection for their own doctrines, instantly took the alarm; and the celebrated contest ensued between the Galenical and Chemical sects, which has given such a controversial tone to the writers of the fifteenth and sixteenth centuries. As this revolt from orthodox authority was in a great degree attributed to the mischievous introduction and unmerited success of Antimonial remedies, so were the preparations of this metal denounced with all the virulence of party spirit;^[108] and upon this occasion, in order to support their ground and oppress and persecute their adversaries, the Galenists actually solicited the assistance of secular power; the Supreme Council of Paris accordingly proscribed its use by an edict in 1566, and Besnier was expelled the faculty of medicine in 1609, for having administered it to a patient. In 1637, Antimonial wine was by public authority received into the number of purgatives; and in 1650, a new arrêt rescinded that of 1566, and again restored Antimony to public favour and general reputation; and before we conclude our remarks upon the revolutionary history of this extraordinary metal, it deserves to be remarked, that this very same government that had with such great virulence, and so little justice, persecuted every practitioner who had shewn any predilection for its use, in the year 1720 actually purchased the secret of an antimonial preparation called Panacea Glauberiana, and which has been since known by the title of Kermes Mineral, from a surgeon of the name of La Legerie, who had acquired the secret from a pupil of Glauber. Before this period the invention of Calomel had taken place; this preparation is first mentioned, although very obscurely, by Oswald Crollius, in his Basilica Chemica, in 1608, and in the same year Beguin described it most fully and clearly under the title of Draco Mitigatus, in his Tirocinium Chemicum, which he published in Paris.

Chemistry, at this period^[109] took possession of the schools, and whilst it was gradually grafted into the theory of medicine, it soon became the only guide to its practice, the absurdity of which has been already dwelt upon.

In tracing the march of chemical improvement during the last century, we cannot but be struck with the new and powerful remedies which it has introduced, and the many unimportant and feeble articles which it has dismissed from medical practice.

In the present century, the rapid progress of Chemistry has outstripped the anticipations of its most sanguine votaries; and even in the department of vegetable analysis, a correctness has been attained, the very attempt at which had been abandoned by the most illustrious chemists of the former age as hopeless and chimerical; let us for instance only compare the results obtained by the Academicians of Paris, and published by Geoffroy, in their analyses of several hundred plants by the operation of heat, with the elegant and satisfactory researches in this branch of science lately conducted in the same country; whilst the former failed in establishing any distinction between the most inert and the most poisonous plants, the latter have succeeded in detecting, separating, and concentrating several of their most subtile constituents. Opium has been at length compelled to confess its secret source of action, and Ipecacuan to yield its emetic element in a state of perfect purity.

Our Pharmacopœias and Dispensatories^[110] have cautiously kept pace with the scientific progress of the age; and in tracing them from their origin to the present time^[111] it is gratifying to observe the gradual influence of knowledge in reducing the number of their articles—simplifying the composition of their formulæ—and improving the processes for their preparation.^[112] Chemistry has also been the means of establishing the identity of many bodies which were long considered as specifically different; thus an extensive list of animal substances has been discarded, since it is known that they owe their properties to one and the same common principle, as to gelatine, albumen, carbonate of lime, &c.; so again the fixed alkaline salt produced by the incineration of different vegetables, has been found to be potass, from whatever plant it may have been obtained, with the exception of sea plants, and perhaps some of the Tetradynamia, the former of which yield Soda and the latter Ammonia. Previous to the Pharmacopœia of 1745, every vegetable was supposed to yield a salt essentially different, and therefore a number of alkaline preparations were recommended, each bearing the name of the particular plant from which it had been procured, as salt of Wormwood—salt of Broom,—Salt of Bean-Stalks, &c.

But, from the very nature and object of a Pharmacopœia, it cannot be supposed to proceed pari passu with the march of chemical science, indeed it would be dangerous that it should, for a chemical theory must receive the seal and stamp of experience before it can become current: a Pharmacopœia however is always an object of abuse, because it is a national work of authority, which is quite a sufficient reason why the ignorant and conceited should question its title to respect, and its claim to utility. “Plures audivi,” says Huxham, “totas blaterantes Pharmacopœias, qui tamen ne intellexerint quidem quid vel ipse pulsus significabat.”

It is very evident, that the greater number of these attacks has not been levelled with any view to elicit truth or to advance science, but to excite public attention, and to provoke unfair discussion for individual and unworthy advantage; their obscure and presumptuous authors vainly hope, that they may gain for their ephemeral writings some share of importance, and for themselves some degree of reputation, if they can only obtain notoriety by provoking a discussion with the College or with some of its responsible members, though such a combat should be sure to terminate in their defeat. Like the Scythian Abaris, who upon being wounded by Apollo, plucked the arrow from his side, and heedless of the pain and disgrace of his wound, exclaimed in triumph that the weapon would in future enable him to deliver Oracles.

It is not to such persons that the observations which are contained in this work are addressed, for with them I am most anxious to avoid a contest, in which, as a worthy Fellow of our College expresses it, “Victory itself must be disgraceful.”

When, however, we are assailed upon every occasion by a gentleman whose talents entitle him to respect, and whose public situation commands notice, I apprehend that a humble individual like myself, may, in the conscientious discharge of a public duty, deliver his sentiments from the chair to which he has been called by his professional brethren, without any risk of compromising the dignity of the College, or of drawing upon himself the charge of an unnecessary and injudicious interference.

The attack to which I chiefly allude, is contained in an historical preface by Mr. Professor Brande, to the Supplement of the Fourth and Fifth Editions of the Encyclopædia Britannica; in which, speaking of the writings of Boerhaave, he says, “The observations which he has made upon the usefulness of Chemistry, and of its necessity to the medical practitioner, may be well enforced at the present day; for, except in the schools of London and Edinburgh, Chemistry, as a branch of education, is either entirely neglected, or, what is perhaps worse, superficially and imperfectly taught; this is especially the case in the English Universities, and the London Pharmacopœia is a record of the want of chemical knowledge, where it is most imperiously required.”

The learned Professor of Oxford, Dr. Kidd, naturally anxious to repel a charge which he considered individually unfair, and to vindicate his University from an aspersion which he felt to be generally unjust, published an animated, but at the same time, a cool and candid defence, to which I have much pleasure in referring you. With respect to the Sister University, my own Alma Mater, I feel that I should be the most ungrateful of her sons, were I, upon this occasion, to omit expressing similar sentiments with respect to the course of chemistry, and that of its collateral branches, which are annually delivered in the crouded schools at Cambridge. Is Mr. Brande acquainted with the discipline of our University?—Is he aware that the chemical chair has been successively filled by Bishop Watson—Milner—Wollaston^[113]—and the late lamented Mr. Tennant?—“Master Builders in the Science.” To say that such men have been the lecturers, is surely a sufficient testimony to shew that the science of chemistry heretofore could not “have been neglected, or what perhaps is still worse, imperfectly taught;” and the zeal and ability displayed by the present Professor, ought to have shielded him from any such attack. Is Mr. Brande aware that the eloquent appeal of Bishop Watson from the chair at Cambridge,^[114] on the general importance and utility of chemistry, gave the first impulse to that public taste for this science which so eminently distinguishes our Augustan age, and which has been the means of founding and supporting the Royal, and other Public Institutions in this Metropolis, as well as in the other towns of the British Empire?

I need make no farther remark upon this part of Mr. Brande’s assertion; the sequel, judging from the construction of the sentence, is evidently intended to be understood as a consequence, viz. and therefore “the London Pharmacopœia is a record of the want of chemical knowledge where it is most imperiously required,” because Oxford and Cambridge Physicians were its Editors. Is not this the obvious construction?

It appears from Mr. Brande’s laconic answer to Dr. Young, published in “The Journal of Science and the Arts,” that his objections are those of Mr. Phillips, contained in his experimental examination of the Pharmacopœia; a work which, I confess, appears to me to furnish a testimony of the experimental tact, subtile ingenuity, and caustic style of criticism, which its author so eminently possesses, rather than a proof of any fatal or material inaccuracy in the Pharmacopœia; and I may urge this with greater force and propriety, when it is considered that, at the time of its publication, I was not a Fellow of the College, and therefore had no voice upon the subject of its composition, and consequently must be personally disinterested in its reputation.

I cannot conclude these observations upon Mr. Brande’s attack, without expressing a deep feeling of regret, that a gentleman, whose deserved rank in society, and whose talents and acquirements must entitle him to our respect, should have condescended to countenance and encourage that vile and wretched taste of depreciating the value and importance of our most venerable institutions, and of bringing into contempt those acknowledged authorities which must always meet with the approbation of the best, and the sanction and support of the wisest portion of mankind.

And I shall here protest against the prevailing fashion of examining and deciding upon the pretensions of every medicinal compound to our confidence, by a mere chemical investigation of its composition, and of rejecting, as fallacious, every medical testimony which may appear contradictory to the results of the Laboratory; there is no subject in science to which the maxim of Cicero more strictly applies, than to the present case; let the Ultra Chemist therefore cherish it in his remembrance, and profit by its application—“Præstat Naturæ voce doceri, quam Ingenio suo sapere.”

Has not experience fully established the value of many medicinal combinations, which, at the time of their adoption could not receive the sanction of any chemical law? We well remember the opposition, which on this ground was for a long time offered to the introduction of the Anti-hectic Mixture of Dr. Griffith,—the Mistura Ferri Composita of the present Pharmacopœia, and yet subsequent inquiry has confirmed upon scientific principles the justness of our former practical conclusion; for it has been shewn that the chemical decompositions which constituted the objection to its use, are in fact the causes of its utility (see Mist. Ferri,); the explanation, moreover, has thrown additional light upon the theory of other preparations; so true is the observation of the celebrated Morveau, that “We never profit more than by these unexpected results of Experiments, which contradict our Analogies and preconceived Theories.”

Whenever a medicine is found by experience to be effectual, the practitioner should listen with great circumspection to any chemical advice for its correction or improvement. From a mistaken notion of this kind the Extractum Colocynthidis compositum, with a view of making it chemically compatible with Calomel, has been deprived of the Soap which formerly entered into its composition, in consequence of which its solubility in the stomach is considerably modified, its activity is therefore impaired, and its mildness diminished.^[115]

On the other hand, substances may be medically inconsistent, which are chemically compatible, as I shall have frequent opportunities of exemplifying. The stomach has a chemical code of its own, by which the usual affinities of bodies are frequently modified, often suspended, and sometimes entirely subverted; this truth is illustrated in a very striking manner by the interesting experiments of M. Drouard, who found that Copper, swallowed in its metallic state, was not rendered poisonous by meeting with oils, or fatty bodies; nor even with Vinegar, in the digestive organs. Other bodies, on the contrary, seem to possess the same habitudes in the stomach as in the laboratory, and are alike influenced in both situations by the chemical action of various bodies, many examples of which are to be found under the consideration of the influence which solubility exerts upon the medicinal activity of substances; so again, acidity in the stomach is neutralized by Alkalies, and if a Carbonate be employed for that purpose, we have a copious disengagement of Carbonic acid gas, which has been frequently very distressing to the patient; lastly, many bodies taken into the stomach undergo decompositions and changes in transitu, independent of any play of chemical affinities from the hidden powers of digestion, some of which we are enabled to appreciate, and they will accordingly form a subject of investigation in the course of the present work.

The powers of the stomach would seem to consist in decomposing the Ingesta, and reducing them into simpler forms, rather than in complicating them, by favouring new combinations.

But every rational physician must feel in its full force, the absurdity of expecting to account for the phænomena of life upon principles deduced from the analogies of inert matter, and we therefore find that the most intelligent physiologists of modern times have been anxious to discourage the attempt, and to deprecate its folly. Sir Gilbert Blane, in his luminous work on Medical Logic, when speaking of the different theories of digestion, tells us that Dr. William Hunter, whose peculiar sagacity and precision of mind detected at a glance the hollowness of such delusive hypotheses, and saw the danger which theorists run in trusting themselves on such slippery ground, expressed himself in his public lectures, with that solidity of judgment combined with facetiousness of expression, which rendered him unparalleled as a public teacher. “Gentlemen,” said he, “Physiologists will have it that the stomach is a mill—others, that it is a fermenting-vat—others again, that it is a stew-pan,—but in my view of the matter, it is neither a mill, a fermenting-vat, nor a stew-pan—but a Stomach, Gentlemen, a Stomach.”

What can illustrate in a more familiar and striking manner the singular powers of Gastric Chemistry, than the fact of the shortness of time in which the aliment becomes acid in depraved digestion? A series of changes is thus produced in a few hours, which would require in the laboratory as many weeks,^[116] while in acute affections of the alimentary canal the functions of the stomach are nearly suspended, and hence under such circumstances, whatever is introduced into this organ remains unchanged, even the nutritious mucilages are not digested.

From what has been said, it is very evident that the mere chemist can have no pretensions to the art of composing or discriminating remedies; whenever he arraigns the scientific propriety of our Prescriptions, in direct contradiction to the deductions of true medical experience,—whenever he forsakes his laboratory for the bed-side, he forfeits all his claims to our respect, and his title to our confidence. It is amusing to see the ridiculous errors into which the chemist falls, when he turns physician; as soon as Seguin found that Peruvian bark contained a peculiar principle that precipitated Tannin, he immediately concluded that this could not be any other than Gelatine, and upon the faith of this blunder, the French, Italian, and German physicians,^[117] gave their patients nothing but Clarified Glue, in intermittent fevers!—But I desist—not however without expressing a hope, in which I am sure my medical brethren will concur, that, should Mr. Brande again condescend to favour us with a commentary upon Boerhaave, he will select that passage in his work, where, alluding to the application of Chemistry to Physic, he emphatically exclaims, “Egregia illius Ancilla est, non alia pejor Domina.”