33 



has no effect upon magnesium chloride. As it appears to be neces- 

 sary to regard the HCO.. ions as the effective element in the former 

 combination, we must conclude that these act beneficially in the 

 presence of Mg and SO^, but are powerless in the presence of Mg and 

 CI. But as calcium carbonate is equally effective as an antidote to 

 magnesium chloride and to magnesium sulphate, it would follow that 

 the power of CI ions to hinder the effect of HCO3 ions disappears in 

 the i:)resence of Ca ions, while, as already noted, CI ions appear to 

 diminish the value of Ca ions as an agency for counteracting 3Ig ions. 

 Comi^arisons such as these show how difficult it is to attempt an 

 interpretation of toxicological phenomena in the light of current 

 chemical and physiological ideas. Possibly determinations of the 

 solubility and degree of dissociation of these different salts in mix- 

 tures may afford some clue to the numerous anomalies. On the other 

 hand, it is difficult to see any justification for using the reactions of 

 organisms in determining the dissociation constants of electrolytes. 

 The many nonconcordant results recently described in the literature 

 can hardly be regarded as throwing discredit upon the dissociation 

 hyi)othesis, but rather as demonstrating the unsatisfactory nature of 

 the method employed for the investigation in hand. 



Sodium sulphate and sodium chloride are equally effective in rais- 

 ing the limit of magnesium chloride (four times). The former is more 

 effective, and the latter decidedh' less so, than in the case of magne- 

 sium sulphate, so that the anions (CI, SOJ and not alone the cathions 

 (Mg, Xa) appear to make their influence felt in these cases. 



SODICM CARBONATE IN MIXTURES. 



Table VI shows results of experiments with mixtures of other salts 

 with sodium carbonate: 



Table VI. — Limits for soclium carbonate in mixtures. 



Xame of salt added. 



Greatest endurable 

 coucentration of 

 sodium carbonate. 



Concentration of the 

 salts added. 



tJj^Jl^^ In parts Infractions In parts per 

 "norr^nf perlOO.OOO of a normal HXMJOUof 

 solution solution. solution. solution. 



None 0.005 



Sodium sulphate , .007.5 



.Sodium chloride \ .0025 



Calciam chloride \ .25 



Magnesium carbonate i .01 



Calcium carbonate .rrj75 



Calcium sulphate i .03 



Calcium sulphate and calcium carbonate ! .03 



36 

 39 

 13 



1.300 

 52 

 39 

 156 

 1.56 



0.01 

 .01 

 .25 



Saturated. 



Saturated. 



Saturated. { 



Saturated. 



80 



58 



1.377 



Saturated. 

 Saturated. 

 Saturated. 

 Saturated. 



As the above table shows, sodium chloride is ineffective as an anti- 

 dote to sodium carbonate; calcium carbonate barely raises the limit 



8287— No. 71—0:? 3 



