. A text-book of comparative physiology for students and practitioners of comparative (veterinary) medicine . les of natural selection. Breeders have both consciouslyand unconsciously, formed races of animals from stocks whichthe new groups have now supplanted; while primitive manhad tamed various species which he kept for food and to assistin the chase, or as beasts of burden. It is impossible to believethat all the different races of dogs have originated from dis-tinct wild stocks, for many of them have been formed withinrecent periods; in fact, it is likely that to the jackal, wolf, andfox,
. A text-book of comparative physiology for students and practitioners of comparative (veterinary) medicine . les of natural selection. Breeders have both consciouslyand unconsciously, formed races of animals from stocks whichthe new groups have now supplanted; while primitive manhad tamed various species which he kept for food and to assistin the chase, or as beasts of burden. It is impossible to believethat all the different races of dogs have originated from dis-tinct wild stocks, for many of them have been formed withinrecent periods; in fact, it is likely that to the jackal, wolf, andfox, must we look for the wild progenitors of our dogs. Dar-win concluded that, as man had only utilized the materialsNature provided in forming his races of domestic animals, hehad availed himself of the variations that arose spontaneously,and increased and fixed them by breeding those possessing thesame variation together, so the like had occurred without hisaid 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. 4- 3 Fia. 40.—Skeleton of hand or fore-foot of six mammals. I. man; II, dog; III, pit;;IV, ox; V, tapir; VI, horse, r, radius; u, ulna; a, scaphoid; b, semi-lunur; c,Iriquetrum (cuneiform); d, trapezium; e, trapezoid; /, capitatum (unciform pro-cess); /•/, hamatum (unciform bone); p, pisiform; ij thumb; 2, digit; 3, middlefinger; 4, ring-finger; 5, little finger. (After Gegenbaur.) origin of living forms in general, believe that the theory ofnatural selection does not suffice to account for the intellectual GENERAL BIOLOGY. 49
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