714 STUDIES IN GENERAL PHYSIOLOGY 
series of experiments were instituted in which the toxic and 
antitoxic salt both had the same anion. 
TABLE II 
Percentage 
Solution of Eggs Yielding 
Embryos 
bere eee 100 c.c. § m NaNO, 8 
Dis te Pete tanks LOO a “« ~+2ec. 7% Ca(NO,). 1 
Biiackwenauls 100 ge £6 + 1 6s 6c 10 
a osectessieieaun 100 “ 6 + 2 ‘“ ‘“ 15 
Dist ag wise 100 ee 6“ +4 6“ “ 15 
Cau aed ete 100 fe ee + 8 ‘“ “ 70 
It is undoubtedly true, therefore, that the addition of 
even a small amount of Ca ions diminishes the toxic 
action of a pure sodium-chloride solution. It can further 
be shown that the concentration of the Ca ions necessary 
to abolish the poisonous effects of a sodium-chloride solu- 
tion increases as the concentration of the latter increases 
(see Table ITI). 
Tables IT and IIT show clearly that the amount of calcium 
necessary to annihilate the poisonous effect of a solution of 
a sodium salt increases with the concentration of the sodium 
salt in the solution. 
The embryos formed in these solutions, rendered harmless 
through the addition of calcium, developed a normal circula- 
tion and lived several weeks. As a rule, however, they did 
not hatch. It was further found that the addition of 5 c.c. 
of a g” CaSO, solution could annihilate absolutely the toxic 
effect of a 3m, 4m, or $m NaClsolution. These experiments 
leave no room for doubt that the presence of a trace of Ca 
ions is capable of rendering inert the poisonous effects of a 
pure sodium-chloride solution. 
3. It was next shown that Sr, Ba, and Mg ions are 
also capable of annihilating the poisonous effects of a 
Digitized by Microsoft® 
