408 EVOLUTION, GENETICS, AND EUGENICS 



But it is perfectly clear thai if the evidence does not go beyond 

 this, nothing is proved that affects the question at issue. It was to be 

 expected that the offspring should show the modification in a more 

 marked degree than their parents did, since the offspring were sub- 

 jected to the modifying influences from birth, whereas their parents 

 were influenced only from the date of their importation. 



What would be welcome is evidence that the third generation is 

 more markedly modified than the second; then there would be data 

 worth considering. Only then would it be necessary to consider 

 Weismann's somewhat subtle discussion as to the influence of climate. 



THE INHERITANCE OR NON-INHERITANCE OF ACQUIRED CHARACTERS 1 



EDWIN GRANT CONKLIN 



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 philan- 

 thropists and yet it is still to a certain extent an unsolved problem. 



Opinions of Lamarck and Darwin. — It is well known that Lamarck 

 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 satirized it in his Biglow 

 Papers in these words: 



"§ome 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 non- 

 sense 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 pangenesis in order to explain the 

 process of the transmission of such characters to the germ cells. 



Weismann's theories. — Weismann introduced a new era in 

 biology by denying the inheritance of all kinds of acquired characters, 

 and by challenging the world to produce evidence that would stand a 



1 From E. G. Conklin, Heredity and Environment (copyright 1919). Used by 

 special permission of the publishers, The Princeton University Press. 



