548 JACQUES LOEB AND HARDOLPH WASTENEYS 
temperatures better in an m/8 Ringer solution than in tap water 
or weaker Ringer solutions. No positive results were obtained. 
Ill. THE ADAPTATION OF FUNDULUS TO HIGH TEMPERATURES 
Fish from the cold room (10° to 14°C.) were kept for lengths 
of time varying from one hour to several hours at 27°C., in an m/4 
Ringer solution, and then put into H.O, m/64, m/32, m/16, and 
m/8 Ringer solution at 31°. It was found that the longer they 
stayed at a temperature of 27° the more resistant they became to 
the temperature of 31°, so that finally they survived at that tem- 
perature even in distilled water. 
One sees that fish that had been kept in m/4 Ringer solution 
for seventy-two hours lived indefinitely in 31° even in distilled 
TABLE 4 
| : a 31° ] 
w | DURATION OF LIFE OF FUNDULUS AT IN | 
PREVIOUSLY EXPOSED TO 
27° IN m/4 RINGER | 7 Pepi 
SOLUTION FOR | HO m/64 m/32 m/16 | m/8 
| es | 
0 hour Palsy 40’ 43’ | 120’ or | indef. | 
| |. indef. | 
1 hour 35! 95’ 150’ 102 | indef. | 
4 hours lite 162) indef. indef. indef. | indef. | 
| ; : : 5 fis bes | 
23 hours | 180’ .| indef. | indef. | indef. | indef. | 
72 hours | indef. | indef. | indef. | indef. | indef. 
water. Itshould be stated that each experiment was accompanied 
by a control experiment with animals that had not been immun- 
ized and in all cases the fish die in less than an hour in 31° in solu- 
tions below m/8. 
Fish kept in the cold room (10° to 14°C.) and put from there 
directly into a solution of 35° nearly all died in a few minutes 
even in the optimal solution of m/4 sea-water or Ringer. Experi- 
ments were undertaken to ascertain the minimum time the fish 
had to be kept at 27° in m/4 sea-water in order to be rendered 
immune to a sudden transfer into m/4 Ringer solution at 35°. 
It should be stated, however, that the fish that had been kept 
at 27° for sixteen and twenty-one hours did not all survive in 35° 
