2 Darwin- Wallace Celebration. 



possibility in the future of any second revolution of Biological 

 thought so momentous as that which was started 50 years 

 ago by the reading of the joint papers of Mr. Darwin and 

 Dr. Wallace, ' ; On the Tendency of Species to form Varieties; 

 and on the Perpetuation of Varieties and Species by Natural 

 Means of Selection," communicated to our Society by Sir 

 Charles Lyell and by Sir Joseph Hooker, whom we have the 

 happiness of seeing with us to-day. 



The papers, it will be remembered, consist of an extract 

 from Mr. Darwin's then unpublished work on Species, for 

 which he had been preparing during the previous 20 years, 

 of an abstract of a letter from him to Asa Gray, the famous 

 American Botanist, and of Dr. Wallace's paper, which he 

 had sent to Mr. Darwin, " On the Tendency of Varieties to 

 depart indefinitely from the Original Type." 



In Mr. Darwin's contributions, the now classic terms 

 " Natural Means of Selection " and " Natural Selection " are 

 used for the first time. In Dr. Wallace's essay the same idea 

 is expressed with equal clearness, as for example in the words 

 " If any species should produce a variety having slightly 

 increased powers of preserving existence, that variety must 

 inevitably in time acquire a superiority in numbers." With 

 both authors the key to evolution is at the same time the key 

 to adaptation, the great characteristic by which living things 

 are distinguished. Darwin and Wallace not only freed us 

 from the dogma of Special Creation, a dogma which we now 

 find it difficult to conceive of as once seriously held " Nee 

 deus intersit, nisi dignus vindice nodus," they afforded a 

 natural explanation of the marvellous indications of Design 

 which had been the great strength of the old doctrine, and 

 themselves, with their disciples, added tenfold to the evidences 

 of adaptation. In like manner, if we are to see further 

 advance now or in the future, any new development of the 

 doctrine of evolution must be prepared to face, fairly and 

 squarely, the facts of adaptation. 



I am proud to welcome, in the name of the Linnean 

 Society, the illustrious gathering which has assembled to 

 commemorate an event, so unpretentious in its circumstances, 

 so profound in its significance. The presence among us of 



