TEE OBIGIN OF SPECIES. 37 



The gist of Mr. Darwin's work is to sliow tliat 

 sucli varieties are gradually diverged into species 

 and genera tlirougli natural selection 1 tliat natm'al 

 selection is the inevitable result of the struggle for 

 existence which all living things are engaged in ; and 

 that this struggle is an unavoidable consequence of 

 several natural causes, but mainly of the high rate at 

 which all organic beings tend to increase. 



Cui'iously enough, Mr. Darwin's theory is grounded 

 upon the doctrine of Malthus and the doctrine of 

 Hobbes. The elder DeCandolle had conceived the 

 idea of the struggle for existence, and, in a passage 

 which would have delighted the cynical philosopher 

 of Malmesbury, had declared that all ISTature is at war, 

 one organism with another or with external ISTature ; 

 and Lyell and Herbert had made considerable use of 

 it. But Hobbes in his theory of society, and Darwin 

 in his theory of natural history, alone have built their 

 systems upon it. However moralists and political 

 economists may regard these doctrines in their original 

 application to human society and the relation of popu- 

 lation to subsistence, their thorough applicability to 

 the great society of the organic world in general is 

 now undeniable. And to Mr. Darwin belon^'s the 

 credit of making this extended application, and of 

 working out the immensely diversified results with 

 rare sagacity and untiring patience. He has brought 

 to view real causes which have been largely operative 

 in the establishment of the actual association and geo- 

 graphical distribution of plants and animals. In this 

 he must be allowed to have made a very important 

 contribution to an interesting department of science, 



