OF ENVIRONMENT 137 



Briefly summarizing the results of the investi- 

 gations cited it may be taken as safely established 

 that individually acquired or induced characters 

 or modifications of existing qualities may be 

 transmitted from one generation to another prac- 

 tically unchanged. The assumption that organ- 

 isms may make direct fitting or adaptive re- 

 sponses of the soma to environmental factors, 

 which may be impressed on the germ-plasm and 

 transmitted to successive generations, has not 

 been confirmed by actual observation or experi- 

 mental tests. 



This tentative conclusion that somatogenic 

 characters are not transmitted is one with which 

 the following facts must always be taken into 

 account: A — ^the physiological mechanism of or- 

 ganisms, particularly of the seed-plants, is one 

 which offers direct means of communication be- 

 tween the soma and the germ-plasm in the form 

 of reproductive elements, and which might per- 

 mit the making of enduring impressions on 

 embryonic tissues during ontogeny, or their 

 effective communication to the egg, or sperm; 

 B — the experimental and cultural test of the 

 effect of repetition of the action of external agen- 

 cies upon the soma in inducing hereditary alter- 

 ation has not yet been seriously attempted, and 

 may indeed include the crucial requisite of the 

 whole matter; C — a great number of structures 

 and functions sustain the closest adaptive relation 

 to environic forces, and important correlations 



