THE NEW EVOLUTION 



specialization in any animal type the more has it 

 departed from a zoologically normal balance. The 

 primitive types in all the major groups are those in 

 which the most perfect balance between all the struc- 

 tural features is maintained. 



The several major groups exhibit a great variety 

 of conditions in the relation of their different struc- 

 tural features to each other; they show a very different 

 balance in their various essential organs. In their 

 embryonic stages the representatives of the various 

 major groups show a close approximation to each 

 other in the gastrula, but are wholly similar to each 

 other only in the germ cell. 



Thus the only fact of cosmic significance in the 

 whole subject of evolution in its broadest sense is the 

 appearance of the single cell. The single cell has 

 inherent in itself the potentiality for development, 

 through selective and progressive reduction in various 

 directions and in various ways, into every form of life 

 which at any time may be capable of existence and of 

 self-perpetuation under the conditions obtaining at 

 that time. 



All animal types are therefore to be regarded, in 

 their relation to cosmic evolution, simply as varied 

 and varying manifestations of the inherent potentiali- 

 ties of the fundamental substance protoplasm. Such 

 a concept contemplates the animal world as in reality 

 but a single unit finding its expression in an infinity 

 of equations all of which, no matter how complicated 

 they may seem, reduce themselves to the same funda- 

 mental term. 



