■496 PROCEEDINGS OF SECTION D. 



tions of the salts of the heavy metals. In such cases the cells were 

 always basic in character. But, as I have previously indicated, the heavy 

 metals stand in a somewhat unique position as regards pioteins, inasmuch 

 as they form insoluble compounds with them ; so that in these rases the 

 reaction between the proteins of the tissue and the heavy metal cations 

 is an almost imbalanced one, the product of the reaction being carried 

 out of the sphere of chemical action as fast as it is formed; so that the 

 reaction does not cease until practically all the proteins in the tissue are 

 combined with the heavy metal cation, and hence possess predominantly 

 basic characters. 



I carried out similar experiments on the influence of electrolytes upon 

 the toxicity of alkaloids (40), and here again I found a marked influence 

 exerted by solutions of electrolytes upon the chemical affinities of tissues 

 placed in them. A large body of evidence, to which reference will be 

 found in my original paper, tends to show that the toxic action of 

 an alkaloid depends upon its forming compounds with the tissues affected; 

 and, I may remark, recent experiments, as yet unpublished, have placed 

 me in possession of still further evidence in support of this view. The 

 alkaloids are basic substances, some of which have also acid characteris- 

 tics. Experiments upon an infusorian fParamoecium), a worm { J'ubifexJ, 

 and a crustacean f GammarusJ, with 14 different alkaloids acting in 

 solutions of a number of different salts, showed that alkaloids which are 

 purely basic in character exhibit a maximum of toxicity when acting in 

 solutions of salts in which the anion has the higher migration velocity, 

 and that alkaloids which are both acid and basic in character show a 

 maximum of toxicity when acting in solutions of salts in which the 

 anion has the higher migration velocity, and also another maximum of 

 toxicity in solutions in which the cation has the higher migration velocity. 

 Thus these experiments confirmed those on staining power. The corres- 

 pondence between theory and experiment in the investigations upon 

 alkaloids extended to details upon which, however, I cannot dwell here. 

 I should mention, however, that the toxicity of a solution was estimated 

 by the reciprocal of the duration of life in the solution, and that the 

 toxicity of the solution of the salt alone was always subtracted from 

 that of the solution of the salt, plus the alkaloid. 



Summing ujj, therefore, our information, derived from the chemical 

 behaviour of tissues placed in solutions of electrolytes, regarding the 

 chemical affinities of the ion-proteid compounds, we may state that the 

 ion-proteids tend to assume the acid or basic properties of the ion derived 

 from the surrounding solution with which they are combined. 



Thirdly, as regards the influence of the concentration of a solution 

 of an electrolyte bathing a tissue upon the properties and amount of 

 the ion-proleid formed. That the older view that the influence of the 

 concentration of the medium upon the cells suspended in it is to be 

 attributed to purely osmotic factors is untenable has been shown, more 

 especially by the experiments of Loeb (41), Wolfgang Ostwald (42), and 

 Osterhout (43). Loeb, experimenting with a marine crustacean ( Gam- 

 marusj, found that they died rapidly in distilled water, but that they 

 died equally rapidly in solutions of cane sugar, dextrose, or ever\ of 

 sodium chloride which were isotonic wdth sea water. They died even more 

 rapidly in a solution containing all the salts in sea water, with the excep- 

 tion of sodium chloride, in the concentration in which they occur in sea 



