CHEMICAL PHYSIOLOGY. 31 



Let me take as an example the subject of osmosis. The laws which 

 regulate this phenomenon through dead membranes are fairly well 

 known and can be experimentally verified; but in the living body there 

 is some other manifestation of force which operates in such a way as to 

 neutralize the known force of osmosis. Is it necessary to suppose that 

 this force is a new one? May it not rather be that our much vaunted 

 knowledge of osmosis is not yet complete? It is quite easy to under- 

 stand why a dead and a living membrane should behave differently in 

 relation to substances that are passing through them. The molecules 

 of the dead membrane are, comparatively speaking, passive and stable ; 

 the molecules in a membrane made of living cells are in a constant state 

 of chemical integration and disintegration; they are the most unstable 

 molecules we know. It is to be expected that such molecules would 

 allow water, or substances dissolved in water, to pass between them 

 and remain entirely inactive? The probability appears to me to be all 

 the other way; the substances passing, or attempting to pass, between 

 the molecules will be called upon to participate in the chemical 

 activities of the molecules themselves, and in the building up and 

 breaking down of the compounds so formed there will be a trans- 

 formation of chemical energy and a liberation of what looks like a 

 new force. Before a physicist decides that his knowledge of osmosis is 

 final, let him attempt to make a membrane of some material which is 

 in a state of unstable chemical equilibrium, a state in some way com- 

 parable to what is called metabolism in living protoplasm. I cannot 

 conceive that such a task is insuperable, and when accomplished, and 

 the behavior of such a membrane in an osmometer or dialyser is studied, 

 I am convinced that we shall find that the laws of osmosis as formu- 

 lated for such dead substances as we have hitherto used will be found 

 to require revision. 



Such an attitude in reference to vital problems appears to be infin- 

 itely preferable to that which too many adopt of passive content, saying 

 the phenomenon is vital and there is an end of it. 



When a scientific man says this or that vital phenomenon cannot 

 be explained by the laws of chemistry and physics, and therefore must 

 be regulated by laws of some other nature, he most unjustifiably assumes 

 that the laws of chemistry and physics have all been discovered. He 

 forgets, for instance, that such an important detail as the constitution 

 of the proteid molecule has still to be made out. 



The recent history of science gives an emphatic denial to such a 

 supposition. All my listeners have within the last few years seen the 

 discovery of the Eontgen rays and the modern development of wireless 

 telegraphy. On the chemical side we have witnessed the discovery of 

 new elements in the atmosphere and the introduction of an entirely 

 new branch of chemistry called physical chemistry. With such examples 



