American Fisheries Society. 67 
aquatic life upon which the young bass feed. Two small ponds 
at the Fish Lakes station were selected and six bass were placed 
in each. The sulphate in the proportion of 1 to 5,000,000 was 
introduced in one of them on April 22. 
A roily condition of the water unaccounted for prevented 
observations of the nesting bass and the date of spawning could 
not be obtained, but on May 8 a fine brood of bass fry was dis- 
covered, proving beyond doubt that the copper did not effect the 
spawning of bass. 
With the disintegration of the algae there appeared myriads 
of daphnia. 
The ponds in which this experiment was tried were of too 
small area to rear the fry to fingerlings, and on June 12 copper 
sulphate 1 to 5,000,000 was applied to a pond of 1.55 acres with 
an average depth of twenty and three-fourths inches. This pond 
was inhabited by adult large-mouthed bass fry and baby finger- 
hngs. The latter were being seined out for distribution. By 
June 22 much of the algae had disappeared, comparatively little 
remaining. Its disintegration caused the water to impart a very 
offensive odor when stirred. Careful observations about the 
pond and of the young fish seined from it daily after the copper 
was administered disclosed no deleterious effects upon the young 
fish. 
The writer was assisted in these experiments by Dr. Geo. 
T. Moore, the discoverer of the valuable uses of copper in water 
supplies, and by his assistant, Karl F. Kellerman. Some labora- 
tory tests made by them showed the following results: 
Large-mouthed black bass 100 eggs uninjured by 1 to 1,000, 
OOO, 
50 one-day old fry uninjured by 1 to 1,000,000. 
50 five-day old fry uninjured by 1 to 1,000,000. 
25 ten-day old fry uninjured by 1 to 1,000,000. 
Crappie, very young fry uninjured by 1 to 1,009,000, 
Fish food is an important item of expense at stations where 
brood fish are carried or young fish are fed for a considerable 
period before distribution. More or less experimental work in 
this direction has been conducted at all such stations of the 
Bureau of Fisheries, and during the past year the work has been 
more systematic than heretofore. The prejudice against the use 
