ADAPTATION OF FISH TO TEMPERATURE 549 
TABLE 5 
PREVIOUSLY IN THERMOSTAT AT PH is DURATION OF LIFE OF FUNDULUS AT 3De 
0 hour | By 
1 hour iy 
3 hours | ou 
6 hours | or 
8 hours 6’ 
16 hours | indefinitely 
21 hours | indefinitely 
44 hours | indefinitely 
While all the fish that had been kept at 27° for forty-four hours 
survived. 
This experiment was repeated with a second set of fish with the 
results shown in table 6. 
TABLE 6 
PREVIOUSLY IN THERMOSTAT AT 27° FOR | DURATION OF LIFE OF FUNDULUS AT 35° m/4 RINGER 
1 hour DE 
3 hours 2’ 
6 eb | : 
8 hours 
16 hours 
| partly ‘ndefinite 
21 hour | | partly indefinite, but better than pre 
24 hours f vious group 
32 hours | 
40 hours ! 
48 hours | in efinite 
65 hours | 
72 hours | 
It seems that if Fundulus are kept more than twenty-four hours 
in a temperature of 27° they can with impunity be put into an. 
m/4 Ringer solution of 35°. If fish are kept from six to sixteen 
hours at 27° and then suddenly transferred to 35° (in m/4 Ringer 
solution) some of them die and some survive; and the tendency to 
survive increases the longer the fish are previously kept at 27°. 
