140 Thirty-fourth Annual Meeting. 
vegetation shriveled, while the streamlets dwindled and finally 
disappeared entirely during the summer months. With these 
changd conditions went the food of the young fry. The breed- 
ing trout failing to reach the old spawning places in the autumn 
were compelled to utilize the gravel beds lower down the 
stream, where the food of the young fry existed in but limited 
quantity. 
Then with the melting of the snows came the spring rise, 
and with it the logs of the lumberman, plowing out the beds on 
the gravel bars, scattering the trout fry and killing many. In 
Michigan, in each recurring spring, the logs plowed up the 
spawning beds of the grayling, destroying the ova almost en- 
tirely for many seasons. To this cause, alone, is to be charged 
the almost total extinction of grayling in Michigan waters, and 
not to over-fishing. Neither have they been driven out by the 
trout, as has been alleged. Before the era of logging trout and 
grayling had existed for all time, and dwelt together in perfect 
amity. 
The mining of metals and the smelting of ores can not be 
operated without water, consequently the streams in the neigh- 
borhood of mines become discolored and impregnated with de- 
leterious matter that destroys, utterly, the food of fish fry, 
covers up the spawning beds with silt and debris, and eventually 
pollutes the stream to such an extent that but few, if any, ma- 
ture fish can survive in them. 
The offal from distilleries, and the sawdust from sawmills, 
likewise settles on spawning beds, so that if any fish eggs are 
deposited they are smothered and the embryo perishes. Chaff 
from the slop of distilleries and sawdust from the mills often 
become lodged in the gills of mature fish, causing inflammation 
and death. 
Coal mining is also fatal to fish life, inasmuch as the wash- 
ing of coal, as now practiced, not only discolors the water, but 
the coal dust is deposited on the spawning beds, and if breathed 
in by fish, old or young, clogs the gills, and from the well- 
known hardness of carbon, irritates and inflames them. 
The waste matter from oil refineries, paper mills, starch fac- 
tories, etc., where poisonous chemicals or noxious substances 
are used or occur as by-products, is very destructive to fish of 
