summer months of higher latitudes ; consisting of wheat, barley, flax, peas, beans, &c. with the culture of the poppy, and the collection of opium, in the very same fields, perhaps, where, in the rainy season, had been grown rice, sorghum, and other tropical grains.
Such are a few general views respecting the Geography of plants in connexion with climate. Between the extreme points of a tropical and a polar vegetation, we might shew a series of gradations : but these would lead into unneces- sary detail ; and the object has, perhaps, been sufficiently gained, if I have been successful in shewing in what way the distribution of plants is connected with climate ; and consequently what is the value of any inferences that may be deduced from their culture in new situations ; and also from vegetable products being found in countries where the plants themselves are unable to grow.
The Animal creation is the next which should attract our attention, or at least be considered in connexion with the vegetable kingdom, whether we adopt the ascending or the descending series. Here we find sensibility superadded to the vital principle, which we first saw in union with matter in the lowest forms of organized vegetation. Inte- resting and instructive as is the study of the forms and habits of the animal world ; indispensable as is an acquain- tance with their internal structure and functions to a scientific knowledge of the anatomy and physiology of the human frame ; these are of comparatively less consequence in a course of Materia Medica : because in proportion as the progress of medicine has brought the art of prescription nearer to its original simplicity, so the crowd of inert and disgusting remedies, introduced by the corrupters of medi- cine, have disappeared from our pharmacopoeias. As animals require for their nutriment matter which has already been organized, either by vegetables or lower grades of animal life, D
