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 diflp erent 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 



