president's address. 21 



problems of life appear now to await solution in the arena of 

 intra-cellular structure and function. 



The older vitalists demanded a I'ecognition of the non- 

 mechanical character of the grosser aspects of living process. 

 Even by the neo-vitalists it is now admitted that at least many 

 of these can be explained " on purely physical and chemical prin- 

 ciples," but they now turn round and calmly tell us that pro- 

 cesses so explainable are not " characteristic of life." Yet it is 

 solely, the ad^'ances in the physico-chemical analysis of grosser 

 function and structure which have enabled us to re-state the 

 problems involved in the newer and more elementary terms of 

 intracellular process. And with regard to the facts involved in 

 the processes above referred to, of development, growth and main- 

 tenance, adaptation, and self-repair, it seems quite unwarrantable 

 to predict that physico-chemical analysis will prove more futile 

 here than at any previous stage of scientiric development. 



It is true, for instance, that the processes of secretion and 

 absorption of material by cells can no longer be conceived as due 

 simply to diftusion and filtration, liut all that necessarily follows 

 from the admission is the concession that the processes are in 

 reality more complicated than was formerly supposed. Apparently 

 there is invohed an actual selection of material on the part of 

 tlie cells concerned. Is such behaviour after all entirely outside 

 the scope of all possible physico-chemical explanation, as the 

 vitalist alleges it to be 1 Verworn remarks upon this very point 

 that " The principle upon which this phenomenon is based is 

 evidently the same as that which controls in general atoms and 

 molecules, namely, affinity. It is surel}^ no less wonderful that 

 an atom of phosphorus unites very easily with an atom of oxygen, 

 but not with an atom of platinum, than that an intestinal epithe- 

 lium-cell takes up fat-droplets, but never pigment-granules. And 

 it is no less comprehensible that a Vampyrella surrounds with its 

 body-protoplasm and digests only Spirogyra threads and no other 

 bodies, than that a di'op of rancid oil, as Gad has shown, sends 

 out amoeboid processes to an alkaline liquid, and uses the alkali 



