774 REPORT— 1902, 



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 knovs^. Is it 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 sub- 

 stances 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 

 transformation 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 comparable to what is called metabolism in 

 living protoplasm. I cannot conceive that such a task is insuperable, and when 

 accomplished, and the behaviour of such a membrane in an osmometer or dialyser is 

 studied, I am convinced that we shall find that the laws of osmosis as formulated 

 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 infinitely prefer- 

 able 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, be 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 Kontgen 

 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 ready to our hands, who can say what further discoveries 

 will not shortly be made, even in such well-worked fields as chemistry and physics ? 



The mention of physical chemistry brings me to what I may term the second 

 head of my discourse, the second striking characteristic of modern chemical 

 physiology : this is the increasing importance which physiologists recognise in a 

 study of inorganic chemistry. The materials of which our bodies are composed 

 are mainly organic compounds, among which the proteids stand out as pre- 

 eminently important; but everyone knows there are many substances of the 

 mineral or inorganic kingdom present in addition. I need hardly mention the 

 importance of water, of the oxygen of the air, and of salts like sodium chloride and 

 calcium phosphate. 



The new branch of inorganic chemistry called physical chemistry has given us 

 entirely new ideas of the nature of solutions, and the fact that electrolytes in 

 solution are broken up into their constituent ions is one of fundamental import- 

 ance. One of the many physiological aspects of this subject is seen in a study of 

 the action of mineral salts in solution on living organisms and parts of organisms. 

 Many years ago Dr. Einger showed that contractile tissues (heart, cilia, &c.) con- 

 tinue to manifest their activity in certain saline solutions. Howell goes so far as 

 to say, and probably correctly say, that the cause of the rhythmical action of the 

 heart is the presence of these inorganic substances in the blood or lymph which 

 usually bathes it. The subject has more recently been taken up by Loeb and his 

 colleagues at Chicago : they con6rm Ringer's original statements, but interpret them 

 now as ionic action. Contractile tissues will not contract in pure solutions of non- 

 electrolytes like sugar or albumin. But difi"erent contractile tissues differ in the 

 nature of the ions which are their most favourable stimuli. An optimum salt 

 solution is one in which stimulating ions, like those of sodium, are mixed with a 

 certain small amount of those which like calcium restrain activity. Loeb considers 

 that the ions act because they affect either the physical condition of the colloidal 

 substances (proteid, &c.) in protoplasm or the rapidity of chemical processes. 



