86 BIOLOGICAL SOCIETY OF WASHINGTON. 



but with his characteristic wisdom he has declined to invoke the 

 odium tlicologicum, correctly judging that the truth must ultimately 

 .assert itself. 



The tendency to vary, then, is a mechanical result of the proved 

 fact of universal movement coupled with the admitted law of natu- 

 ral selection. By means of the former all plants and growing parts 

 of plants are perpetually exploring their immediate surroundings in 

 search, as it were, for conditions favorable to development. By 

 means of the latter they are able to avail themselves of such favor- 

 able conditions when found. Nothing further than this is required 

 to complete the natural explanation of all the phenomena presented 

 by the organic world, and thus, at last, the whole domain of biol- 

 ogy is emancipated from teleological fetters, and placed on the 

 high plane of rational investigation. 



In conclusion, let me simply say that, while we can but deeply 

 mourn the irreparable loss which science has sustained in the death 

 of Charles Darwin, we have still the highest grounds for congratu- 

 lation in the fact that he lived to complete that great work which, 

 next to the " Origin of Species," will, I firmly believe, be awarded 

 by posterity the highest place, viz. ,"The Power of Movement in 

 Plants; " for, while the former auspiciously opened the great debate 

 by stating the profoundest of all biological problems, the latter has 

 fittingly closed the argument by answering the last objection. 



