76 Thirty-fourth Annual Meeting. 
purity, but was mixed with spring water, the latter constituting 
perhaps one-third of the supply in part of the trough system 
and less than one-eighth part in the others. All of the fry were 
hatched in the supply containing the smaller proportions of 
spring water, and some of the experiments were begun there, 
but all were flnally moved to the troughs fed by other mixture. 
The temperature ranged from 50 to 64 degrees F. 
The brook trout treated were all derived from eggs received 
from private parties in Massachusetts, who were rearing trout 
for the food market, and were of inferior quality and lacking 
in vigor, as shown by the history of the control lot, No. 1768, 
out of which were taken the experimental lots, 4 in number, 
consisting of 1,000 fry each, A, B, C and D. On May 23, the 
control lot began to feed, and thenceforth received chopped 
hogs’ liver four times daily. Lot 1768 A was not fed until 5 
days later; 1768 B was compelled to wait for its first feed 9 
days; 1768 C, 14 days; 1768 D, 19 days. As each of them 
reached the termination of its fast it was fed thenceforth like 
the control lot, 4 times daily. The results noted were mainly 
in the list of deaths, which was kept with great care to secure 
accuracy. ‘The number dying was recorded daily, and for the 
purpose of this paper the record will be quoted from the begin- 
ning of the fast to 15 days after its close. The loss record of 
1768 A, thus covered 20 days, and during that time the mortal- 
ity amounted to 22, or a little more than 2 per cent. The record- 
period of the 9-day fasters, 1768 B, was 24 days, and the deaths 
therein were 60, or 6 per cent. The 14-day fasters, lot 1768 C, 
in 29 days lost 517, or nearly 52 per cent. The 19-day fasters, 
in 34 days lost 776, or nearly 78 per cent. Thus it would appear 
that in this series, the losses were severer the longer the fast, 
and in the case of the longest fast the loss approached annihil- 
ation. 
Let us now see how these losses compared with those suffered 
by the control lot, which had been fed constantly from the start, 
4 times daily. Comparing the latter with the 5-day fasters 
(1768 A) the control lot lost four and four-tenths per cent while 
the fasters were losing two and two-tenths per cent, that is, if 
these results be attributed wholly to the food, the generous feed- 
ing doubled the mortality. Compared with the 9-day fasters 
