170- DEVELOPMENT AND HEREDITY. 



greatest part of the period of growth. This ' Law 

 of precocious inheritance,' as Wurtenberger calls 

 it, also holds — for it obviously coincides with the 

 law of abbreviated development — for living ani- 

 mals." 1 This passage is one of a very large 

 number in Professor Elmer's work on Organic 

 Evolution in which not only the facts recorded, 

 but also the very phraseology, lends itself un- 

 changed for the illustration of the present theory. 



These examples given in this chapter are not in- 

 tended to set forth exactly how the parts attained 

 their present form and function, but to indicate the 

 class of forces which has produced the given result. 

 We know that these forces do act, and we know also 

 that the action of any force must produce its effect. 

 When we admit the existence of the hereditary im- 

 pulse as I have described it, with its capacity for 

 modification by the action of these forces through 

 long series of generations, then we have the expla- 

 nation of development. And, understanding the 

 action of the forces and the nature of the hered- 

 itary impulse, we have no necessity to suppose any 

 other occult factor or agent. We see the result 

 before us, we know that the forces act, and the 

 theory of the hereditary impulse makes the process 

 intelligible and the result logical. 



1 Organic Evolution, p. 31, Eimer. Trans, by Cunningham (Mac- 

 millan & Co.). 



