122 American Fisheries Society 



The question arises: Do these fish retain or eliminate 

 the copper after a time ? This may be partially answered 

 by the following : 



One hundred fish were placed in copper chloride solu- 

 tion containing thirty parts to the million, for two hours. 

 At the end of this time twelve were taken for immediate 

 analysis. The remainder were placed in running sea wa- 

 ter, and after fourteen days ten more were taken for 

 analysis. After twenty-five days had elapsed another 

 sample of ten were taken for analysis. The three analy- 

 ses agreed very closely, and seemed to show that even 

 though removed from the source of pollution the copper 

 content of the fish did not diminish. 



During the experiment twenty-one fish died in the run- 

 ning water, the most of them( seventeen) during the first 

 four days. The copper seems to have an accumulative 

 effect. 



Nickel chloride, ferric-ammonium-citrate, and potas- 

 sium-di-chromate were also used, and analyses of the fish 

 made after having been in various concentrations of 

 these salts in sea water for different periods of time. 

 None of these salts appeared to be toxic to the fish, how- 

 ever, and they could survive in concentrations of about 

 two hundred parts per million for a week or two. This 

 concentration was about the maximum used, and the 

 time the longest that the experiments were run. Analyses 

 showed that the fish had absorbed the metals neverthe- 

 less. That they were non-toxic may have been due to 

 the fact that the salts in sea water were antagonistic to 

 those employed. This is sometimes the case, as Loeb has 

 shown. 



Among other salts used in sea water and found to be 

 non-toxic, were cobalt chloride, manganese chloride and 

 zinc sulphate, but mecuric chloride, cadmium nitrate and 

 sodium arsenate were found to be highly toxic. Analyses 

 of the fish exposed to these salts, just mentioned, have 

 not been made as yet so it is impossible to draw further 

 conclusions. 



