176 



BULLETIN OF THE BUREAU OP FISHERIES 



survive when all other individuals^ tested^under the same conditions had died; and, 

 conversely, a rise of 1° for only a short time sometimes was followed by the death 

 of fishes that normally would have been expected to survive. 



So far as possible, uniform aeration was maintained, the streams of bubbles 

 being controlled by the use of clamps on the rubber air tubes. A number of experi- 

 ments in which it appeared that the deaths might have been due to weakness or 

 stoppage of the aeration were discarded. 



34° 



"Normal" individuals. 



36° 



6 individuals-4 trials 6 indivlduals-4 trials 3 individ's.3 trials 

 Acclimatization 30°, 1 day. 



Sflg 



6 lndividuals-4 trials 3 individuals-2 trials 



Acclimatization 30°, 4 days. 



36 c 



38° 



5 individuals-4 trials 



Acclimatization 10°, 1 day. 

 30° 32? 



6 individuals-5 trials 



Acelim. 10°, 4 days 

 30° 



2 individuals,! trial 3 individuals, 2 trials 4 individ's.4 trials 



Acclimatization 10°, 4 days. 

 . 3i£ 



Acelim. 10°, 15 days 

 ano 



7 individuals. 5 trials 4 individuals, 4 trials 6 Individ' s. 3 trials 



Fig. 3. — Effects of high temperatures on young bluegills. For explanation of symbols see 



Figure 1 



NUMBER OF TRIALS 



The term "trial" as used in this paper refers to a 24-hour test at a given tem- 

 perature on the specimens in one container. The term "series" is used to designate 

 the group of trials performed at a given temperature on similar individuals of the 

 same species which had received the same preliminary treatment. The various 

 trials in one series usually were made on different days, although in some instances 



