RELATIONS TO OTHER SCIENCES 565 



which lead to decline or extinction; so that it completes a definite 

 life-cycle with an inevitable end. Indeed, even in smaller matters, it is 

 often not difficult to express sociology in the terms of paleontology. 

 Newberry, for example, long ago pointed out that the evolution of 

 warfare between human communities corresponds exactly with that 

 between fishes in the course of their long history - - the first tendency 

 being towards protection by thickening the armor until a maximum 

 is reached, when this method is abandoned and skillful movement 

 gradually supersedes it. Other examples might be cited, and will 

 readily occur to any one who is familiar with the details of the past 

 history of any group of organisms. It must, however, suffice now 

 merely to conclude by emphasizing a remark made at the outset, that 

 these wider aspects of the subject can only be fully appreciated when 

 paleontology is taught and learned as an independent branch of 

 knowledge. 



