FISHES. 29 



exists among the races, and the indefatigable 

 assaults committed by man upon them, it is pro- 

 bable that the actual average of life among Fishes 

 is of comparatively short duration. 



Tenacity of life must be distinguished from 

 its durability. In this property much difference 

 is found amongst fishes. Mr. Yarrell observes 

 that those species which swim near the surface 

 of the water, have a high standard of respiration, 

 a low degree of muscular irritability, great ne- 

 cessity for oxygen, die soon — almost immediately 

 on being taken out of the water — and have flesh 

 prone to rapid decomposition ; of these, Mackerel, 

 Salmon, Trout, and Herrings are examples. On 

 the contrary, those that live near the bottom 

 have a low standard of respiration, a high degree 

 of muscular irritability, and less necessity for 

 oxygen : these sustain life long after they are 

 taken out of the water, and their flesh remains 

 good for several days: Carp, Tench, Eels, the 

 diflerent sorts of Skate, and all the Flat-fishes 

 are examples of this class. Some species, as 

 the Eels and the OjjJiiocephali, continue to ex- 

 hibit vigorous tokens of life, under inflictions 

 that would be fatal to most other animals ; the 

 removal of the skin, and even the division of the 

 body into pieces, not immediately producing 

 death. 



The power of sustaining extremes of tempera- 

 ture, found in this Class of animals, may perhaps 

 be considered an indication of their low place 

 in the scale of organization. Broussonet found, 

 by experiments, that several species of fresh- 

 water Fishes lived many days in water so hot 

 that the hand could not be held in it a single 



