REACTIONS OF FISHES TO SALTS 



271 



2. Resistance to potassium salts 



Solutions (O.OIN) of the chloride, nitrate, and sulphate, were 

 made up in tap water and a small blue gill (3-5 gram) introduced 

 into a liter of each; the results are shown in table 8. 



The action of the potassium salts in tap water was checked 

 by placing a fish in a O.OIN solution of the most toxic one, i.e., 

 the sulphate, in distilled water. The reactions of this fish were 

 very peculiar. After 3 days in the solution it was noticed that 

 the fish was losing its equilibrium and it was expected that it 

 would die in a few hours. On the next day, however, it was still 



TABLE 8 



Showing the resistance of small blue gills to .OIN concentrations of jpotassium salts 



in solution in tap water 



DYING TIME IX 



alive and for 10 days more it lived spending much of the time 

 lying on its side but righting itself when touched with a glass 

 rod. Its movements were sluggish and stiff, much as though 

 it were dying from fungus disease. In all, the fish lived for 

 14 days in O.OIN potassium sulphate solution, which is over three 

 times as long as a fish of the same size lived in the same strength 

 solution in tap water. The long-drawn-out death of the fish 

 is not a phenomenon that is peculiar to potassium salts, however, 

 for it was noted that another small blue gill w^hich was in an 

 ammonium nitrate experiment in distilled water at the same 

 time, gave a similar reaction. This latter fish swam about for 

 three days on its side with the body bent into the bow-shape 

 that often distorts fish after death, especially when they dry 

 out. This suggests that the distortion may have been due to 

 osmotic changes in the tissues. 



