460 EVOLUTION AND ANIMAL LIFE 



Huxley further shows that 



" the brain is only one condition out of many on which intellectual 

 manifestations depend, the others being, chiefly, the organs of the 

 senses and the motor apparatuses, especially those concerned in pre- 

 hension and in the production of articulate speech. '^ 



Selenka finds that man and the man-apes agree in the manner 

 and relation of the young in the mother-body to that body in 

 that both man and man-apes have but a single disclike placenta, 

 while the other apes have two opposed disc placentas. And 

 Friedenthal finds that while the blood serum of man is poisonous 



to, and destroys the red 

 blood corpuscles of all 

 other animals experi- 

 mented on, these animals, 

 including fishes, amphib- 

 ians, .reptiles, birds, and 

 mammals, among which 

 T? onn T>- u+ V, 1 ^ 1 f* J • 1,+ f + + latter were lemurs and 



Fig. 290. — Right hand at left, and nght foot at 



right, of a two-months-old human embryo, NeW-World {AtelcS and 



showing similar position of the first digit PithecOSClUrUs) and Old- 



(thumb, great toe) in each. (After Wieders- ixr i i //^ 77 



i^gi^^) World {Cynocephalus, 



Macacus and Rhesus) 

 monkeys, it does not injure the corpuscles of the man-apes 

 (orang, gibbon, and chimpanzee). This immunity exists only 

 among closely related animals as the horse and donkey, dog 

 and wolf, and hare and rabbit. From which it is evident that 

 man and the man-apes have nearly identical blood. 



The second "ancestral document,^' embryology, emphasizes 

 the common origin of man with that of the higher vertebrates 

 and notably with that of the anthropoids. The embryos of 

 man and apes develop in a fashion precisely parallel. In both, 

 as in all other mammals, the early presence of gill slits furnishes 

 evidence of a descent from a fishlike ancestry. The same 

 evidence is given in the embryonic growth of reptiles and birds. 

 In the development of the human child some simian traits 

 appear, these being wholly or partly lost in the more advanced 

 stages. Among these is the lanugo or general covering of long 

 hairs, more or less developed in certain stages of fcetal growth, 

 but lost entirely before birth. The curving upward of the feet, 



