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American Fisheries Society 



the antagonistic effect of sodium chloride on calcium chloride. 

 In these experiments, Table I, the antagonism of the sodium 

 chloride did not, at any concentration tested, amount to more 

 than the additive effect of the sodium chloride solution itself. 

 That is, there was always more or less of a decrease in the 

 survival tirrie of the fish when the sodium chloride was added, 

 over that in the pure calcium chloride solution. By compar- 

 I. Data on the blunt-nosed minnow, Pimephales notatus (Rafinesque), 



WHEN KILLED IN 0.297 N. CALCIUM CHLORIDE TO WHICH DIFFERENT 



AMOUNTS OF SODIUM CHLORIDE HAVE BEEN ADDED 



[Column one gives the normality of the sodium chloride of the 0.297 N. calcium 



ing Table I with experiments on which the same fish, Pime- 

 phales notatus (Rafinesque), were killed at 22.8° C. (Powers, 

 1921, Table I), it will be seen that the actual antagonistic 

 effect of the sodium chloride was increased up to the largest 

 amount of sodium chloride added. That is, the falling off of 

 the survival time of the fish was less rapid in the mixture 

 of calcium and sodium chlorides per actual concentration of 

 salts than an equivalent concentration of pure calcium chloride 

 or sodium chloride. 



