244 



CHEMICAL CHARACTER OF POTASSIUM 



concentrations of the salts mentioned. Table VI gives the results of 

 an experiment. The first horizontal row gives the molecular concen- 

 tration of NaCl, KCl, RbCl, and CsCl in which the m/5 solution of 

 LiCl was made up. The figures in the next horizontal rows give the 

 percentage of eggs which formed embryos. 



The table shows that the addition of NaCl did not protect the Fim- 

 dulus eggs against the toxic effects of LiCl, while the KCl, RbCl, and 

 CsCl had a protective or antagonistic effect. The protective effect 

 of these salts is considerably less than that produced by a salt with a 

 bivalent cation since in the latter case 80 per cent or more of the eggs 

 form embryos in a m/5 solution of LiCl. 



These examples may suffice to show that the action of the potas- 

 sium ion in the phenomena of antagonism (which underlie the physi- 

 ological balance of ions in salt solutions) is in agreement with the 

 purely chemical character of this ion, i.e. its position in the periodic 

 table; and that hence there is no reason to attribute its physiological 

 action in these cases to some other factor; e.g., its extremely minute 

 radioactivity. 



SUMMARY. 



1. It is shown that the NH4 ion acts in cases of antagonism on the 

 egg of Fundulus more like the K ion than the Na ion ; this corresponds 

 to the fact that in its general chemical behavior the NH4 ion resembles 

 the K ion more closely than the Na ion. 



2. It is shown that the tolerance of sea urchin eggs towards the Li 

 ion can be increased 500 per cent or more if at the same time a certain 

 amount of Na ion is replaced by K, Rb, or Cs ions. Since in the 



