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.” THE INFLUENCE OF SOIL, CULTURE, CLIMATE, AND SEASON. The facts hitherto collected upon this subject are so scanty and unsatisfactory, that I introduce its consideration in this place, rather with a wish to excite farther enquiry, than with any hope of imparting much additional information. There can be little doubt, but that Soil, Culture, Climate, and Season,[118] may very materially influence the active properties of a medicinal plant; while the two latter of these causes may as essentially change the type and character of a disease, and modify the vital susceptibility of the patient; the natives of the south of Europe, for instance, do not bear bleeding, and other modes of depletion, so well as those of the north. This must be admitted to its full extent, or it will be extremely difficult to explain the contradictory and even opposite opinions, and to reconcile the conflicting testimonies of the physicians of different countries, with respect to the efficacy of the same remedy, in similar diseases.