[Draft] 
[London, 19 July 1878] 

Dear Sir, 

In yesterday’s no. of Nature I see an announcement of a lecture 
to be given by you at the natural scientists’ conference in Kassel 
‘on the relation of Darwinism to Social Democracy’.*” 

That the advocates of Darwinism in Germany would not be able 
to evade the necessity of adopting a position vis-a-vis the socialist 
world outlook was something socialists had foreseen long before 
Mr Virchow so amiably tipped the wink.“°? Whatever that position 
may turn out to be, it can only contribute to the clarification of the 
situation and of men’s minds. On the other hand, it is desirable 
from both points of view that this should be done in full 
awareness of the facts. 

By way of making a contribution of my own, I am taking the 
liberty of sending you by post a copy of my work Herr Eugen 
Dühring’s etc, which has just come out.**' In it, I have en- 
deavoured to give, among other things, an outline of the relation 
of scientific socialism to the propositions of modern theoretical 
natural science in general, and to Darwin’s theory in particular. 
The passages relating to Darwinism are marked. 

With your permission, I shall in due course and from my own 
standpoint subject your lecture to the kind of ruthless criticism 
which alone does justice to free science and which any man of 
science must welcome, even when applied to himself.*”