THE THIRST OF SALTED WATER 651 



in very small amount they simulate absolutely the action of 

 enzymes. At first the action follows a straight-line law, which 

 is proof that the ions are not evenly distributed in the solution, 

 as they should be according to the dissociation hypothesis. 



Another and the most forcible of all arguments perhaps 

 against the hypothesis is the proof which has been given, in 

 case after case, by Brereton Baker and others, that the occur- 

 rence of chemical change is dependent not on dissociation but 

 on the association in one conducting system of at least three 

 components, one of which is an electrolyte. 



Another argument is the preposterous limitation which the 

 hypothesis imposes on our ability to explain chemical change, 

 as it is only applicable to electrolytes, not to the vast host of 

 organic compounds excepting organic acids and alkalies. 



But what has weighed more than almost any other considera- 

 tion with me has always been the absolute and uncompro- 

 mising attitude of objection to the hypothesis taken by Fitzgerald 

 at British Association meetings and especially in his Helmholtz 

 Memorial Lecture. He alone appeared to me always to under- 

 stand the situation and to appreciate the difficulties. 



The conceptions developed by Van't Hoff, Arrhenius and 

 Ostwald were never applicable to any but the weakest solutions. 

 Strangely enough, these leaders of the movement elected from 

 the beginning to sail under the flag which has been so 

 aggressively waved by Sir Victor Horsley of late and made 

 their grog by dipping only the wetted stopper of the spirit 

 bottle into a tumblerful of water. And over and over again they 

 and their followers made the mistake of considering only the 

 volume of the solution as a whole ; consequently they always 

 went wrong when dealing with concentrated solutions. No two 

 moderately concentrated solutions prepared by their method 

 were of comparable strength. 



Daylight was first let into the subject when Morse and 

 Frazer showed that simple and consistent results were arrived 

 at, even in the case of concentrated solutions, by dealing always 

 with a definite mass of water and varying the proportion of solute 

 — by using weight-normal solutions, as they are now termed. 

 Independently I introduced the same practice into my laboratory 

 and gave my reasons for so doing in June 1906 in a communica- 

 tion to the Royal Society on the "Origin of Osmotic Effects." 



But how is the thirst of salted water — the superior activity 



