270 



MORRIS M. WELLS 



monium carbonate is very toxic in distilled water, that standing 

 does not lessen its toxicity greatly nor does it that of the sulphate 

 in tap water, and finally that the ammonium sulphate is no longer 

 toxic in tap water when the carbonates have been converted into 

 sulphates by the addition of enough sulphuric acid to make 

 the water neutral to methyl orange. 



TABLE 



Showing the resistance of fishes to .OIN concentrations of {NHi)2C03 in distilled 

 water; the effect of standing upon the toxicity of ammonium salt solutions; and the 

 non toxicity of a solution of {NHi)2S0i in tap ivater when the carbonates have been 

 converted into sulphates. 



The experiments upon the resistance of fishes to ammonium 

 salts show clearly that ammonia in any form is toxic to fishes 

 in water containing carbonates. Since practically all natural 

 waters contain a greater or lesser amount of the carbonates in 

 solution as such, or as bicarbonates, the introduction of even 

 very small amounts of ammonia into these waters will be very 

 detrimental to the fishes. Table 7 shows, on the other hand, 

 that the carbonates are not necessary to the immediate existence 

 of the fishes, i.e., the water need not be alkaline to methyl orange 

 as Marsh ('07) claimed. It may of course be that the carbonates 

 are necessary to a successful completion of the life history of 

 some fishes, or to the continued existence of certain species. This 

 point has not been worked out so far as I am aware. 



