20 president's address. 



all along, and would evidently have led to far more steady and 

 continuous advance." 



The writer then contrasts organism with mechanism with 

 reference to the phenomena of self-repair, and adaptation to 

 change in environment, of which he remarks that physico-chemical 

 physiology has failed to give any account, although they may be 

 traced in every elementary physiological process. And positive 

 harm is done when the attention is directed away from these 

 characteristic features of organisation, instead of towards these, 

 as the assumption of a vital principle did. 



On these grounds it is alleged that vitalism embodied not only 

 a negative but a positive working hypothesis of great value. 



Now I quite fail to see, in the considerations stated, any 

 .sufficient reason for refusing to persevere in the mode of explanation 

 by which admittedly we haA'e been led up to the present problems 

 of cell-physiology. Nor can I see wherein, in regard to the 

 phenomena mentioned, vitalism has opei'ated as a working 

 hypothesis distinct from those principles of physics and chemistry 

 which we elsewhere invoke in explanation of changes of the motion 

 and configuration of a material system. 



The facts of development, growth, maintenance, adaptation and 

 self-repair, to which Dr. Haldane alludes, are facts which are as 

 patent to the physico-chemical investigator of life as to the vitalist. 

 He has no desire to blink their occurrence. For him, also, the 

 nature of the processes having those particular aspects, forms part 

 of the subject matter of scientific research. It cannot be admitted 

 that there is a single feature of the three lines of discovery 

 adduced as instances of the operation-of " vitalism" as a working 

 hypothesis, which is in its nature beyond the recognition of 

 science, working to explain phenomena from the physico-chemical 

 point of view. As a matter of fact the present aspect which each 

 of these problems presents is the fruit, not of vitalistic hypothesis, 

 but of a triumphant reduction of all the grosser aspects of living 

 process as cases of the operation of ordinary mechanical principles. 

 It is not the reproach, but the reward, of modern physical biology 

 that the result of its brilliant analysis is tliat the essential 



