Thus comparative anatomy proves to the satisfaction of every unprejudiced and critical student the significant fact that the body of man and that of the anthropoid ape are not only peculiarly similar, but they are practically one and the same in every important respect. The same two hundred bones, in the same order and structure, make up our inner skeleton; the same three hundred muscles effect our movements; the same hair clothes our skin; the same groups of ganglionic cells build up the marvellous structure of our brain; the same four chambered heart is the central pulsometer in our circulation; the same thirty-two teeth are set in the same order in our jaws; the same salivary, hepatic, and gastric glands compass our digestive process; the same reproductive organs insure the maintenance of our race. It is true that we find, on close examination, certain minor differences in point of size and shape in most of the organs of man and the ape; but we discover the same, or similar, differences between the higher and lower races of men, when we make a careful comparison--even, in fact, in a minute comparison of the various individuals of our own race. We find no two persons who have exactly the same size and form of nose, ears, eyes, and so forth. One has only to compare attentively these special features in many different persons in any large company to convince one's self of the astonishing diversity of their construction and the infinite variability of specific forms. Not infrequently even two sisters are so much unlike as to make their origin from the same parents almost incredible. Yet all these individual variations do not weaken the significance of the fundamental similarity of structure; they are traceable to certain minute differences in the growth of the individual features. CHAPTER III OUR LIFE Development of Physiology in Antiquity and the Middle Ages: Galen--Experiment and Vivisection--Discovery of the Circulation of the Blood by Harvey--Vitalism: Haller--Teleological and Vitalistic Conception of Life--Mechanical and Monistic View of the Physiological Processes--Comparative Physiology in the Nineteenth Century: Johannes Müller--Cellular Physiology: Max Verworn--Cellular Pathology: Virchow--Mammal Physiology--Similarity of all Vital Activity in Man and the Ape