Besides these, there appear to be other subordinate objects of inquiry, which he has hitherto, to a certain extent, overlooked; namely, that medicines seem to be objectionable from the injury which they do to those functions which are the vehicles of their operation, the uncertainty also of their effects as influenced by association, the uncertainty of their continuance as dependent on the same and other causes, the difficulty of removing their bad effects, and the injury they do to the intellectual functions in making man entirely the creature of direct impression instead of reflection. I shall now, then, proceed to point out the mode of obviating this state. * * * * * These seem to me to be points eminently worthy of consideration, and the best mode of obviating the objections they involve, is a greater attention to natural theory and arrangement. But, in order perfectly to remedy these great defects, the cultivation of physiology is primarily necessary. As far as the accumulation of facts goes, it has, however, already been cultivated, and that most assiduously. But before these accumulated facts can afford a principle of medicine, they must afford a theory of physiology, and, before they can afford this, they must be arranged according to their relations to each other. I may here observe, that the sciences alone afford theories, the arts admit merely of principles upon which these reasonings or theories are applied to the wants of man. Thus, in every step of their progress, the arts must implicitly depend upon the sciences. Now medicine is purely an art and admits of a principle derived from physiology by which the theories of that science may be applied to the cure of diseases. As, however, no general theory of physiology exists, it becomes necessary to inquire what systematic arrangement can be given to its facts, as strictly founded on those of anatomy, in order to obtain one. And I know none so unexceptionable as that arrangement which I have already publicly delivered, nor any general theory so rational as the one which results from it. I shall now, therefore, restate these arrangements, and then try their applicability to the medical art. * * * * * Anatomy I divide into three parts, namely, that which considers the mechanical or loco-motive organs, that which considers the vital organs, and that which considers the intellectual organs. Under the mechanical or loco-motive organs, I class, first, the bones which support the rest of the animal structure; second, the ligaments which unite them; and, third, the muscles which move them. Under the vital organs, I class, first, the organs of digestion, the absorbent surfaces, and the vessels which absorb from these surfaces; second, the heart, lungs and blood-vessels which derive their contents (the blood) from the absorbed lymph; and, third, the organs of secretion which separate various matters from the blood.