° 
156 Thirty-fifth Annual Meeting 
decomposable matter discharged into it. The water absorbed 
large quantities of oxygen during the fall and winter and only 
a part of this stock has been exhausted, most rapidly at the bot- 
0 30 10 15 20nG 25 



F1G. 9—Green Lake, Sept. 6. 1905. 

tom and at the upper part of the cool water—the two places 
where the greatest amount of chemical activity seems to take 
place. The oxygen nowhere becomes so low as to make it im- 
possible for a considerable number of animals to live in the water 
and in the mud beneath it. 
