438 
BULIyETiN OP THE BUREAU OF FISHERIES. 
ery, and many larger and smaller springs in the pond itself, and that this supplies the 
greater portion of the water to the hatchery. This water is supplemented by a large 
spring B, forming one system of water supply, while the water from springs C and F 
forms the other, the two systems uniting in race 12. The water coming from the large 
pond is aerated in fountains K and L. Springs D and E tap a vein running in a northerly 
direction at a depth of about 15 to 25 feet. The water from these two springs is now 
used exclusively in the hatchery building for hatching this season’s spawn. The large 
pond A maintained in 1907 an unknown number of fish living under wild conditions, 
being fish which from time to time were placed in the pond, where they had then shifted 
for themselves. The pond is grass-grown about the banks, has a plentiful growth 
upon its bottom, and presents practically an ideal approach to wild conditions. (Fig. 82.) 
In 1906 a brown trout approximately 2 years old was found dead at the outlet 
of the big pond, and on examination presented two well-developed tumors at the junc- 
tion of the gills. This was the first evidence of the disease which the superintendent 
had noted. In September, 1907, pond A was emptied, a large portion of the fish in it 
escaping into the brook. After cleaning the bottom, removing the grass, etc., the 
pond was stocked with about 6,000 brook trout fry hatched in the hatchery, and sys- 
tematic feeding with liver was, for the first time, practiced in this pond. From August 
to October, 1908, a few of the yearling fish in the large pond were found dead with visi- 
ble tumors. In October the fish in the lower races supplied from the big pond also began 
to die in sufficient numbers to attract attention, and a large proportion of these were 
found also to have visible tumors. During the summer of 1908 not less than 3,000 fish, 
exclusively brook trout, died in this hatchery with visible tumors. During this period 
of the outbreak some 1 75 adult rainbows held in one of the lowermost ponds, to which 
ran the water from the spring running through the races seriously affected, remained 
free from the disease, with the exception of i fish found late in the season. Some 
4,000 yearling brown trout from Caledonia remained free from evidence of visible 
tumors; as did also some 220 four-year-old brown trout from the same source. 
During the summer of 1909 epidemic conditions obtained in this hatchery in more 
aggravated form than in any previous year. The stock fish as well as the fry were fed 
almost exclusively on beef livers, obtained twice a week from the Buffalo abattoirs. A 
large proportion of this liver fell to the bottom of the large pond and there decayed. 
The food not eaten up in the races was brushed out frequently enough to prevent con- 
tamination. About 200 pounds of beef livers were fed weekly in the hatchery. A 
number of times livers were found with large single or multiple abscesses. 
The stock fish in the hatchery in 1909 consisted of the following, some lots of which 
may be recognized as having figured in the occurrences in the hatchery of 1908 — 125 to 
150 rainbows held in concrete race 13; 3,000 two-year-old brown trout from Caledonia 
in races 22 and 23; 76 older brown trout; and 700 to 750 brook trout of varying size 
and age. During the course of the summer the rainbow trout retained their relative 
immunity to the disease, only 7 developing visible tumors during the summer, notwith- 
standing the position of pond 13, receiving water from both water supplies, all of it 
running through troughs and concrete tanks above, in which the disease was very active. 
