Thomas. — Metallic Salts 121 



The temperature of the solutions ranged from about 

 sixty-eight to seventy-four degrees Fahrenheit, which was 

 not greatly different from the temperature of the water 

 in the harbor. Records show the water there to range 

 from about sixty-four to seventy-four degrees, during the 

 period of the experiments. 



The fish were fed during the experiments just before 

 the solutions were changed, and sea mussels were used as 

 food. 



Experiments performed using copper sulphate showed 

 that the fish absorbed the copper. While still in a healthy 

 condition, the fish were taken from the solutions contain- 

 ing the copper, thoroughly washed, and water run 

 through the alimentary tract to insure the removal of all 

 copper not absorbed into the tissue of the fish. 



After having been in a solution containing thirty parts 

 to the million for forty-eight hours, it was found that the 

 fish had absorbed .00079 per cent of their wet weight, 

 or .0035 per cent of their dried weight. 1 The copper was 

 determined by drying the fish to constant weight after 

 washing, and then analyses for the copper made on the 

 dried sample. About fifty copper determinations were 

 made upon fish from varying concentrations of copper 

 sulphate, and it was found that the fish would absorb the 

 copper proportionally to the concentration of the solu- 

 tion, and also to the time exposed. 



Copper chloride was used as well as the sulphate in 

 some of the experiments, but it appears that not as much 

 copper was absorbed in a given time from solutions of 

 copper chloride, as from solutions of copper sulphate con- 

 taining the same amount of copper. The sulphate also is 

 apparently much less toxic than the chloride. In solu- 

 tions of the sulphate, thirty parts to the million, it was 

 impossible to keep the fish for much longer than ninety- 

 six hours, but in solutions of the chloride of the same 

 concentration the fish succumbed in a much shorter 

 period. 



2 For detailed results see Jowr. Biol. Chem., Vol X, No. 1, May, 1912. 



