NERVOUS SYSTEM OF VERTEBRATES. 



73 



comparative anatomist, and that of Turgenief, the great 

 novelist — were about four pounds. It varies slightly 

 in different races, being greater in the superior races, 

 but not so much greater as might have been expected. 

 There are only two- animals that have larger brains than 

 man, viz., the elephant, whose brain is about eight 

 pounds, and the whale, whose brain is about five pounds. 

 The enormous size of these animals is sufficient reason. 

 (p) Size relative to the Body or to Rest of the Nervous 

 System. — This is far more significant than the last. The 

 brain of the highest animal of like size, viz., the gorilla 

 is only about one third that of man, viz., fifteen 

 ounces. Below this there is a constant decrease of rela- 

 tive size. This is shown in the following table. Of 

 course we only take averages of these various classes. 



c 



LASSES. 



Brain to body. 



Brain to nervous system. 





I : 1,000 

 I : 1,000 

 I : ioo 

 I : 200 

 1 : 50 



i:7= + 



1 :5= £ 





5:1=5 times. 







3:1=3 times. 







30 : 1 = 30 times. 







There are some things in this table which require ex- 

 planation. First, it is seen that there is no superiority 

 in reptiles over fishes in brain to body weight, but there 

 is in the relation to the rest of the nervous system. 

 Again, it is seen that birds are apparently superior to 

 mammals. The reason of this is that, as a law, small 

 animals have larger brains proportionately than large 

 animals. Now birds, as a rule, are smaller animals than 

 mammals. Indeed, some of the smallest birds, such as 

 the humming bird and the kinglet, have actually larger 

 brains proportionately than man. The same is true of 

 the smallest mammals, such as the mouse. But there are 

 other things spoken of later, viz., fineness of organiza- 



