DABWIN S METHOD OF STUDY. 1 35 



of natural selection flashed on me. Of all the minor points, 

 the last which I appreciated was the importance and cause 

 of the principle of divergence." 



During the leisure and retirement in which Darwin lived 

 after his return, he occupied himself, as we see from this 

 letter, first and specially with the study of organisms in 

 their cultivated state ; that is, domestic animals and garden 

 plants. This was undoubtedly the most likely way to 

 arrive at the Theory of Selection. In this, as in all his 

 labours, Darwin proceeded with extreme care and accuracy. 

 With wonderful caution and self-denial, he published nothing 

 on this subject during a period of twenty-one years, from 1837 

 to 1858, not even a preliminary sketch of his theory, which 

 he had written as early as 1844. He was always anxious to 

 collect still more certain experimental proofs, in order to be 

 able to establish his theory in a complete form, and on the 

 broadest possible foundation of experience. While he was 

 thus aiming at the greatest possible perfection, which might 

 perhaps have led him never to publish his theory at all, he 

 was fortunately disturbed by a countryman of his, who, 

 independently of Darwin, had discovered the Theory of 

 Selection, and in 1858 sent its outlines to Darwin himself, 

 with the request to hand them to Lyell for publication in 

 some English journal. This was Alfred Wallace, one of the 

 boldest and most distinguished scientific travellers of modern 

 times. For many years Wallace had wandered alone in the 

 wilds of the Sunda Islands, in the dense primitive forests of 

 the Indian Archipelago ; and during this close and compre- 

 hensive study of one of the richest and most interesting 

 parts of the earth, with its great variety of animals and 



