272 THE SHARK. 



state of siifFering. It is only in the cold-blooded 

 animals that we meet with it to such an extent ; 

 in the warm-blooded animals it occurs, but in a 

 very slight degree. 



Blumenbach, in his Manual of Natural His- 

 tory, thus mentions the reproductive power and 

 independent vitality with reference to the Am- 

 phibia : — "The extraordinary strength of the 

 reproductive power in several Amphibia, and 

 the astonishing facility with which the process 

 is carried on, depend, if I mistake not, on the 

 great magnitude of their nerves and the dimi- 

 nutive proportion of their brain. The former 

 parts are, in consequence, less dependent on the 

 latter ; hence the whole machine has less powers 

 of motion, and displays less sympathy ; the 

 mode of existence is more simple, and ap- 

 proaches more nearly to that of the vegetable 

 world than in the warm-blooded classes ; but, 

 on the contrary, the parts possess a greater 

 individual independent vitality. Since, in con- 

 sequence of this latter endowment, stimuli 

 which operate on one part, or one system, do 

 not immediately affect the whole frame by sym- 

 pathy, as in warm-blooded animals, we are en- 

 abled to explain the peculiar tenacity of life 

 which is displayed under various circumstances 

 in this class — viz. frogs still continue to jump 



