xxiv CHARLES DARWIN 393 



to a totally opposite conception of one of the most important 

 operations of nature. 



Such a revolution as this, with all its momentous con- 

 sequences to the study of zoology and botany, effected in so 

 short a space of time, is, as has often been said, without a 

 parallel in the history of science, and it is one the full 

 significance of which those who have not lived through it, and 

 been workers at biology in both the pre-Darwinian and post- 

 Darwinian epochs, must find difficulty in realising. 



There is, moreover, no doubt but that this rapid conversion 

 was much facilitated by the fascinating nature of the theory of 

 the operation of natural selection in intensifying and fixing 

 variation, as originally propounded in these rooms independently 

 and simultaneously by Darwin and by Wallace. This theory 

 has been subjected to keen criticism, and difficulties have 

 undoubtededly been shown in accepting it as a complete 

 explanation of many of the phenomena of evolution. That 

 other factors have been at work besides natural selection in 

 bringing about the present condition of the organic world, 

 probably eveiy one now admits, as, I need not say, Darwin 

 did himself. This, however, is not the occasion to enter 

 into a critical examination of this large and complex subject. 

 Indeed, the time seems scarcely yet come when we can do so 

 with the necessary calmness and impartiality. Prejudices on 

 the one hand and on the other, and the cloud of side-issues 

 which were aroused when the theory was first promulgated, 

 and which prevented many from understanding what was 

 really implied by it, still hover around, and many of us 

 deem it best to rest with suspended judgment not only 

 upon this, but upon the various other hypotheses put forward 

 to account for the origin of species, and to turn again with 

 increased interest and zeal to investigate the facts upon 

 which these hypotheses are based. No one can deny that, 

 whatever opinion may ultimately prevail regarding Darwin 

 and his works, the controversies that have gathered round them 

 have proved a marvellous stimulus to research, and have given 

 new life to investigations into a great variety of subjects, 

 subjects so diverse as palaeontology, morphology, embryology, 

 the geographical distribution, the habits, and the life-history 



