PRESIDENTIAL ADDRESS. 45 



truly impossible our theory of evolution must undergo material 

 changes. We must completely abandon the Lamarckian prin 

 ciple, while the principle of Darwin and Wallace, viz. , natural 

 selection, will gain an immensely increased importance" (p. 

 423)- 



A CRITIQUE OF WEISMANN. 



I have now, as I believe, fairly if not fully stated, chiefly in 

 the language of its founder, the Neo-Darwinian theory, and 

 before passing to consider what has been said on the other side, 

 and the position of the Neo-Lamarckians in general, I would 

 like to pause a moment in order to offer a few reflections of my 

 own upon Weismann's teachings. I am emboldened to do this 

 the more not only because I have not seen the exact point of 

 view from which they especially strike me touched upon by 

 others in the voluminous discussion which has grown out of 

 them, but also because what I shall say will be based entirely 

 upon his own statement of the facts, and therefore the objec 

 tion that, not being an embryologist, I am not competent to 

 weigh the considerations from that side (which I would freely 

 admit), cannot properly be raised. 



The question is whether, accepting the continuity of the 

 germ-plasm, accepting the nature which he ascribes to the fer 

 tilized ovum with its multitudes of ancestral plasms out of 

 which selections are made, accepting his explanation of the 

 meaning of the first and second polar bodies, accepting his 

 differentiation into reproductive and somatic cells, and all the 

 other details which he brings forward, many of which are, of 

 course, only hypotheses, there do not still remain grounds on 

 which to base a theory of the transmission of certain kinds of 

 acquired characters, and especially those of a strictly functional 

 nature. In fact, the question seems to me rather to be whether 



