American Fisheries Society. 159 
How great an effect the condition of the gases may have on 
lakes can perhaps be well illustrated by a lake whose gases have 
not yet been investigated. Mr. Hankinson who is studying Wal- 
nut Lake in Michigan, has been telling me today of the results 
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Fic. 11—Elkhart Lake, Aug. 23, 1906. 
he has found in the study of the life of that lake. The lake is 
about a mile in length and half that in breadth, and 110 feet in 
depth. It is a lake that is not far different in these conditions 
from Rainbow Lake, Okauchee Lake, Nagowicka Lake and num- 
erous other lakes in Wisconsin. 
Jn Walnut Lake as I am told, the bottom is very thickly 
