340 FROM THE GREEKS TO DARWIN 



not have this author in mind nor contemplate any- 

 great extremes of transformation. Darwin held 

 to his original proposition, handed down from 

 Leibnitz, 'Natura non facit saltum,' concluding: 

 "It would take a great deal more evidence to 

 make me admit that forms have often changed 

 by saltum''^ 



The idea of natural selection came to Darwin 

 in the year 1838 through the suggestion of Mal- 

 thus,^ who, in turn, had probably borrowed it 

 from Buff on. He was at the time unaware of any 

 of the distinct anticipations of his theory. His 

 attention was called to Naudin's paper in 1859; 

 to Matthew's article in 1860; to that of Wells in 

 1865. Some one, also, called his attention to Aris- 

 totle and Empedocles. It is possible that his eye 

 may have caught the passage in St. Hilaire sug- 

 gesting the idea, without his conscious recollec- 

 tion of it. The strong passage in Erasmus Dar- 

 win's poem may also have survived in his mem- 

 ory. Yet as far as Darwin knew, the idea of the 

 'struggle for life' came first from Malthus; it 

 grew upon him in reading de Candolle, W. Her- 

 bert, and Lyell, of whom he said, "Even they 

 have not written strongly enough." The force of 

 this 'struggle' gradually intensified itself in his 

 mind to a point where he believed it was such that 



"^Life and Letters. Letter to Hooker, February, 1860. 

 2See Impressions of Great Naturalists, 1928, pp. 77-9. 



