330 READINGS IN EVOLUTION, GENETICS, AND EUGENICS 
But it is perfectly clear that 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 paraits 
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' 
EDWIN GRANT CONKLIN 
Few questions in biology have been discussed so fully and so 
fruitlessly as this. It isa 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: 
‘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 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. 
