408 MR. DARWIN's theory of the origin of CHAr. XXI. 



port ttiose views, or to combat the principal objections which 

 the scientific world entertained against them. 



JSTo decided step in this direction was made until the pub- 

 lication in 1858 of two pajjers, one by Mr. Darwin and 

 another by Mr. Wallace, followed in 1859 by Mr. Darwin's 

 celebrated work on "The Origin of Species by Means of 

 Natural Selection ; or, the Preservation of favored Eaces in 

 the Struggle for Life." The author of this treatise had for 

 twenty previous years strongly inclined to believe that varia- 

 tion and the ordinaiy laws of reproduction were among the 

 secondary causes always employed b}^ the Author of nature, 

 in the introduction from time to time of new sjjecies into the 

 world, and he had devoted himself patiently to the collecting 

 of facts and making of experiments in zoology and botany, 

 with a view of testing the soundness of the theory of trans- 

 mutation. Part of the MS. of his projected work was read 

 to Dr. Hooker as early as 1844, and some of the principal 

 results were communicated to me on several occasions. 

 Dr. Hooker and I had repeatedly urged him to publish 

 without delay, but in vain, as he was always unwilling to 

 interrupt the course of his investigations; until at length 

 Mr. Alfred R. Wallace, who had been engaged for years in 

 collecting and studjang the animals of the East Indian 

 archipelago, thought out, independently for himself, one of 

 the most novel and inq^ortant of Mr. Darwin's theories. 

 This he embodied in an essay "On the Tendency of Varieties 

 to dejjart indefinitely from the original Type." It was written 

 at Ternate, in Februar}-, 1858. and sent to Mr. Darwin, with a 

 request that it might be shown to me if thought sufticiently 

 novel and interesting. Dr. Hooker and I were of opinion that 

 it should be immediately printed, and we succeeded in per- 

 suading Mr. Darwin to allow one of the MS. chajDters of his 

 "Origin of Species," entitled "On the Tendency of Species 

 to form Varieties, and on the Perpetuation of Sijecies and 



