222 



FACIAL ANGLE. 



nor is an arm the less an arm because it is a " diverging 

 appendage." In the same spirit a critic might write: 

 "Newton calls this earth a 'planet,' and the moon a 'sa- 

 tellite;' for me the earth is an earth, and the moon is a 

 moon. One must not strive to make an ouranology out 

 of a system of metaphysics." After the first recognition 

 of a thing, one may seek to penetrate, and succeed in 

 knowing, its essential nature, and yet keep within the 

 bounds of nature. 



In no class of vertebrate animals is the progressive 

 superiority of the cranium over the face marked by such 

 distinct stages as in the mammalia. Various methods 

 of determining these proportions have been proposed; 

 but the only satisfactory one is by comparing vertical 

 sections of the skull, as in the series figured in the cuts 

 47—52. 



In the cold-blooded ferocious crocodile (Fig. 47), the 



Fiff. 47. 



CROCODILE. 



cavity for the brain, in a skull three feet long, will 

 scarcely contain a man's thumb. Almost all the skull is 

 made up of the instruments for gratifying an insatiable 



Fiff. 48. 



ALBATROSS. 



