Ill 



THE SELECTION THEORY 

 By August Weismann. 



Professor of Zoology in tlie University of Freiburg {Baden). 



I. The Idea of Selection. 



Many and diverse were the discoveries made by Charles Darwin 

 in the course of a long and strenuous life, but none of them has had 

 so far-reaching an influence on the science and thought of his time 

 as the theory of selection. I do not believe that the theory of 

 evolution would have made its way so easily and so quickly after 

 Darwin took up the cudgels in favour of it, if he had not been able 

 to support it by a principle which was capable of solving, in a simple 

 manner, the greatest riddle that living nature presents to us, — I mean 

 the purposiveness of every living form relative to the conditions of 

 its life and its marvellously exact adaptation to these. 



Everyone knows that Darwin was not alone in discovering the 

 principle of selection, and that the same idea occurred simultaneously 

 and independently to Alfred Russel Wallace. At the memorable 

 meeting of the Linnean Society on 1st July, 1858, two papers were 

 read (communicated by Lyell and Hooker) both setting forth the 

 same idea of selection. One was written by Charles Darwin in Kent, 

 the other by Alfred Wallace in Temate, in the Malay Archipelago. 

 It was a splendid proof of the magnanimity of these two investigators, 

 that they thus, in all friendliness and without envy, united in laying 

 their ideas before a scientific tribunal : their names will always shine 

 side by side as two of the brightest stars in the scientific sky. 



But it is with Charles Darwin that I am here chiefly concerned, 

 since this paper is intended to aid in the commemoration of the 

 hundredth anniversary of his birth. 



The idea of selection set forth by the two naturalists was at the 

 time absolutely new, but it was also so simple that Huxley could 

 say of it later, "How extremely stupid not to have thought of 

 that." As Darwin was led to the general doctrine of descent, not 

 through the labours of his predecessors in the early years of the 



