THE NEW PHYSIOLOGY. 



do, the only answer is that it is part of the nature of 

 reality that they do so. It is only from actual observa- 

 tion of them that we can predict their behaviour ; and 

 to predict we must make use, not of the conception of 

 " things," and their definite and limited " properties," 

 but of the distinctive conception, based on actual obser- 

 vation, of fife. The ideal conceptions of the physical 

 sciences are good enough tools for many practical pur- 

 poses, but not for grappling with the phenomena of life. 

 Darwin emphasised the fact of variation, but without 

 pointing out its characteristic feature as adaptation. 

 To my mind this is a serious defect in his argument. 

 Organisms struggle, not for any sort of existence, but 

 for their own specific sort of existence ; and in whatever 

 direction heritable variation may occur, and whether 

 it be in the direction of further development or of de- 

 grnfiatym the variation has the distinctive character 

 of adaptation. In Mendeiian variations, no less than 

 in other variations, organic wholeness and continuity 

 dearly. In the structural and 

 or variations resulting from 

 the acfidrnU of the reproductive process, this wholeness 

 and continuity are just as evident as in the case of 

 injuries or diseases which have been recovered from. 



point of view of pure biology, the struggle 

 blind straggle. But in so far as organ- 

 this is no longer the case, and the 

 theory does not apply. Adaptation is no 

 I do not, however, propose to discuss in 

 fce ^ft iiMi for evolution of psychical 

 facts. 



physiology of Darwin s time 



