DARWIN AND WALLACE 39 



of the same process. Thus year by year the stock is 

 improved. Any new feature that is favorable helps 

 its possessor to survive, and, if happily mated, will 

 show itself after a while in the entire group. This, 

 in brief, is the underlying idea of Natural Selection, i 

 as Darwin conceived it. 



In 1842, at Lyell's suggestion, Darwin wrote a 

 short sketch of his ideas which he, two years later, 

 expanded into a somewhat larger account. The manu- 

 script of these early views of the theory was com- 

 pletely lost and has only been recovered within the 

 last few years. It was recently published under the 

 editorship of Charles Darwin's son, Francis. It is 

 astonishing to see how clearly the first short sketch 

 states the underlying conception which all of Dar- 

 win's subsequent work amplifies. Hooker was con- 

 stantly urging Darwin to write out his whole theory 

 in the form of a book, and Darwin had begun to do 

 so in 1856. 



Meanwhile, down in the Moluccas, Alfred Russell 

 Wallace had been lying sick of a fever contracted 

 during his exploring expedition in that neighborhood. 

 He had been studying the distribution of the animal 

 life of the Malay -Archipelago. Overcome by sick- 

 ness, as he lay in bed, he began to think over a book 

 which he had read not long before, "Malthus on ' 

 Population." Wallace had been pondering on the 



