III 
THE SELECTION THEORY 
By AuGust WEISMANN. 
Professor of Zoology in the University of Freiburg (Baden). 
I. Tue 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 Ist 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 Ternate, 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 
