Page:An Essay on the Antiquity of Hindoo Medicine.djvu/34

 sable as it is for us to understand the arrangements which they adopt, and the places which the objects we wish to examine occupy in the scheme of nature, do not embrace all that is requisite respecting the substances we have to employ as medicines, even independent of their uses as such. For those which we find most useful as remedies may occupy little of the attention of the naturalist ; as we only employ them when they have ceased to be of use to the objects of his care ; or at least they may never engage his notice in the way in which we view them. A knowledge of natural bodies implies also an acquaintance with their physical states and chemical composition. The former consists in the examination of such properties as their hardness, elasticity, specific gravity, powers of electricity or refraction ; all principal objects of attention in Natural Philosophy, a science which should form a part, not only of professional, but of general education. As students of medicine, I know not how the admirable mechanism of the human body, the circulation of its fluids, or the effects of atmospherical vicissitudes with respect to temperature, density, or moisture, as affecting especially the functions of respiration and perspiration ; or the general effects of bght, heat, and electricity on the human system, can be well understood, unless we study these general powers, and see how they control or affect almost every function. For if we do not understand their operation on the animal eco- nomy, when in a state of health, we are not likely to do so when we wish to employ them as general remedies in disease. These great powers, heat, light, electricity, and magnetism, come under the cognizance of the chemical, as well as of the natural philosopher, though in somewhat different points of view ; the former considering them more as agents effecting changes, and the latter as great prin- ciples of nature and powers in motion.