SEVENTH ANNUAL MEETING 49 



perature which eggs, fry, and adults of different species can 

 stand without being killed. He found the egg to be more re- 

 sistant to high temperatures than was the young fish and prob- 

 ably also than the adult. At 85° F. (29.4° C.) both the young 

 and the old fishes were dead while the eggs still lived to hatch 

 into normal, vigorous larvae. These results are not entirely 

 satisfactory however, for one experiment is stated to have 

 been performed upon the eggs, young, and adult of a given 

 species under similar conditions. Day (1886) observed fish in 

 the government garden in Madras, where, in December 1866, 

 he found the maximum daily temperature of the water to be 

 72° F. (22.2° C.) He states that the Indian carp thrives in 

 the lower rivers where the temperature at mid-clay rises to 

 92° F. (33.3° C.) Carter (1887) gives a table of fishes 

 which are sensitive or hardy in warm waters. He includes 

 both marine and fresh water species giving the average max- 

 imum temperatures which species from the two habitats can 

 stand. These maximum temperatures do not differ much for 

 the two habitats being 50°-71° F. (14.4°-21.6° C.) for the 

 fresh water species mentioned and 58°-71° F. (14.4°-21.6°C.) 

 for those from salt water. 



There are recorded cases where fishes are reported to have 

 inhabited much higher temperatures, but most of these records 

 are not well authenticated. Such cases will be found in the lit- 

 erature cited. There are also many records of fishes having 

 endured low temperatures without injury. Many of these 

 records are common knowledge and must be taken for what 

 they are worth. There are, however, some definite experi- 

 ments upon the relation of fishes to low temperature. Heath in 

 1883 tells of freezing several species of fishes in solid blocks 

 of ice. He found that species thus frozen would regain their 

 normal activities upon slow thawing. Other species were not 

 so resistant, while all the species he tried died if kept in the 

 frozen condition for more than a few hours. Pictet (1893) 

 reports a number of experiments of the same sort. He kept 

 gold fish at 0° C. for 24 hrs., and then slowly cooled the water 

 to -8° to -15° C. The fishes were frozen solid and were as 

 brittle as the ice. Upon thawing they became normal again 

 and swam about the pan as before. When cooled to below -20° 

 C. they could not be revived. 



Much of the value of such data as the above is lost because 

 of the failure of the workers to give specific names and ac- 

 curate reports of temperatures and other experimental condi- 

 tions. Thus there are numerous observations and speculations 



