In order to arrange Animal Physiology, it is only necessary to substitute the term “functions” for “organs;” and that science will likewise involve, in application, the physiology of mineral and vegetable bodies, and be, in its turn, capable of instant adaption to medical science. Thus, the functions also are divided into Mechanical, Vital and Intellectual. The mechanical functions are subdivided into that of support, that of connection, and that of loco-motion. The vital functions are divided into that of absorption, that of circulation, and that of secretion. The intellectual functions are divided into that of sensation, that of mental operation, and that of volition. A circle of functions, I may observe, thus exists in animals, which exists not in minerals or vegetables, because volition, the last of the intellectual functions, connects itself to the mechanical ones, by rendering them subservient to it in loco-motion. Thus the first and the last of these functions are as intimately connected as any of the intermediate ones, and a beautiful circle of organic function and organic influence is formed. The plan of the course will, therefore, be precisely the same with that which I have proposed for Anatomy and Physiology in general. I. In that part of the course which relates to the mechanical organs and functions, will be explained the structure and uses, _1st_, of the bones which support the rest of the animal machine; _2dly_, of the ligaments which unite it; and _3dly_, of the muscles which move it. II. In the first part of the course which relates to the vital organs and functions, will be explained the structure and uses, _1st_, of the organs of mastication, deglutition and digestion, of the absorbent surfaces, and of the vessels which absorb from these surfaces; _2dly_, of the heart, lungs and blood-vessels, which derive their contents, (the blood), from the absorbed lymph; and, _3dly_, of the organs of secretion, which separate various matters from the blood. Throughout this division in particular, the analogies from vegetables will be explained. III. In that part of the course which relates to the intellectual organs and functions, will be explained the structure and uses, _1st_, of the organs of sense which receive impressions from external objects; _2dly_, of the brain, where these impressions excite ideas; and, _3dly_, of the spinal marrow and nerves, where volition results from the last. In this division, will be also explained, as founded upon original observations, certain criteria of the various degrees of the sensitive, perceptive and voluntary powers possessed by different animals, as well as the nature of sensation, perception and volition themselves. As in physiological enquiries, comparative anatomy and comparative views alone can destroy an hypothesis or transmute it into a theory, I shall throughout the course introduce all its principal facts.