WORLD-THOUGHTS. 323 



CHAPTER XXIX. 



WOKLD-THOUGHTS. 



T ET us trace these world-thoughts further. We shall 

 -&quot; find the same story thrice-recorded. 



Every body knows that the domestic dog outranks the 

 ox, while he is himself outranked by the chimpanzee. Still 

 lower than the ox in rank is that aquatic mammal, the 

 whale, which to every judgment seems just on the sepa 

 rating line between mammals and fishes, while higher than 

 the chimpanzee, both in his organization and his intelli 

 gence, is the being, Man. These several forms belong all 

 to the class of mammals, and represent so many orders of 

 that class. Each class of the animal kingdom is composed 

 of different grades of creatures, which mark the different 

 orders of the class. The criteria by which we determine 

 relative rank amongst animals are various. Within the 

 limits of a class, superiority of rank is denoted by aerial 

 respiration, and inferiority by aquatic respiration. Corre 

 spondingly, merely aquatic habits, even with aerial respi 

 ration, as in whales, show that the affinities are downward. 

 Even the endowment of wings marks a grade below those 

 forms fitted to travel on the surface of the solid earth. 

 Then, again, a multiplication of similar parts denotes infe 

 riority, as is illustrated by the fact that some of the mar 

 supial quadrupeds of Australia possess fifty-four teeth, and 

 some dolphins one hundred and ninety, while the typical 

 number for mammals is forty-four. Thus, also, insects have 

 but six legs, while their inferiors, the spiders, have eight, 

 and myriapods an indefinite number. Inferiority is equal- 



