. A text-book of comparative physiology for students and practitioners of comparative (veterinary) medicine. Physiology, Comparative. 48 COMPARATIVE PHYSIOLOGY. from his researches. He was convinced that they had all been derived from a few wild representatives, in accordance with the principles of natural selection. Breeders have both conscioiisly and unconsciously, formed races of animals from stocks which the new groups have now supplanted; while primitive man had tamed various species which he kept for food and to assist in the chase, or as beasts of burden. It is impossible to believe tha
. A text-book of comparative physiology for students and practitioners of comparative (veterinary) medicine. Physiology, Comparative. 48 COMPARATIVE PHYSIOLOGY. from his researches. He was convinced that they had all been derived from a few wild representatives, in accordance with the principles of natural selection. Breeders have both conscioiisly and unconsciously, formed races of animals from stocks which the new groups have now supplanted; while primitive man had tamed various species which he kept for food and to assist in the chase, or as beasts of burden. It is impossible to believe that all the diflperent races of dogs have originated from dis- tinct wild stocks, for many of them have been formed within recent periods; in fact, it is likely that to the jackal, wolf, and fox, must we look for the wild progenitors of our dogs. Dar- win concluded that, as man had only utilized the materials Nature provided in forming his races of* domestic animals, he had availed himself of the variations that arose spontaneously, and increased and fixed them by breeding those possessing the same variation together, so the like had occurred without his aid in nature among wild forms. Evolutionists are divided as to the origin of man himself ; some, like Wallace, who are in accord with Darwin as to the. i 3 Fig. 49.—Skeleton of hand or fore-foof of six mammals. I, man; II, dog; HI, pig; IV. ox; V, tapir; VI. horse, r, radius; «, ulna; a, scaphoid^ i, semi-lunar; c, triquetnim (cuneiform^; d, trapezium: e, trapezoid; f, capitatnm (unciform pro- cess); g, hamatum (unciform bone); p, pisiform; 1', thumb; 8, digit; 3, middle finger; 4, ring-finger; 5, little finger. (After Gegenbaur.) origin of living forms in general, believe that the theory of natural selection does not suffice to account for the intellectual. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrati
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