80 Contributions to the Biology of Freshivater Fishes 



The questions of the variation and composition of the dissolved 

 gases are now under consideration, together with the composition of the 

 water at varying seasons. 



The conclusions to be drawn from this series of observations are : 



1. That deforestation considerably alters the character of the water 

 flowing from hillsides so far as fish life is concerned. 



2. That the altered water in this instance has a very detrimental 

 effect on fish Ufe especially in the young stages. 



3. That too high acidity of the peat water may cause the coagulation 

 of the mucous on the gills, and sides of the fish, which may be fatal. 



4. That a careful control and adjustment of the acidity of the water 

 is necessary to ensure the non-appearance of this bloom, and Ume water 

 or chalk is the most effective. 



{Received January \%th, 1922.) 



