Influence of Environment 237 



tion." We now know that this expresses only a fraction of the 

 truth. The fate of a part is primarily determined by its proto- 

 plasmic organization and only secondarily by its position. 



These are only a few illustrations of the many kinds of abnor- 

 mal development which may be caused by changed environment or 

 by unusual functional activities. At all stages of ontogeny the 

 course of development may be altered by extrinsic stimuli but 

 earlier stages may be more profoundly influenced than later ones. 



D. INHERITANCE OR NON-INHERITANCE OF 

 ACQUIRED CHARACTERS 



Few questions in biology have been discussed so fully and so 

 fruitlessly as this. It is a problem of the greatest interest not 

 only to students of biology but also to sociologists, educators and 

 philanthropists and yet it is still to a certain extent an unsolved 

 problem. 



Opinions of Lamarck and Darwin. It is well known that La- 

 marck taught that characters due to desire or need, use or disuse, 

 and to changed environment or conditions of life were inherited 

 and thus brought about progressive evolution. Long ago desire 

 or need was repudiated as a factor of evolution. Lowell satir- 

 ized it in his Biglow Papers in these words : 



"Some filosifers think that a fakkilty's granted 



The minnit it's felt to be thoroughly wanted, 



***** 



That the fears of a monkey whose holt chanced to fail 

 Drawed the vertibry out to a prehensile tail." 



Darwin wrote to Hooker, "Heaven forfend me from Lamarck's 

 nonsense of adaptation from the slow willing of animals" ; 

 but although he repudiated this feature of Lamarckism he held 

 that characters due to use or disuse and to changed conditions of 

 life might be inherited and he proposed his hypothesis of pan- 

 genesis in order to explain the process of the transmission of 

 such characters to the germ cells. 



