219 



and the animal was very weak. A frog also, whose 

 temperature was 44, when put into a cold mixture, 

 soon fell down to 31; and beyond this point it was 

 not possible to lessen the heat without destroying 

 the animal *. A toad being placed in cold water 

 just deep enough not to cover his mouth, the whole 

 was put into a cold mixture between IO and 15. 

 The water froze around the toad, and, as it were, 

 closed him in, but he did not die, and therefore was 

 not frozen. Why the animals, mentioned in these 

 experiments, died before they were frozen, while 

 those which are exposed to the atmosphere in very 

 cold climates do not die, is a point which Mr Hunter 

 does not pretend to determine ; not knowing the 

 difference, he says, between the effects of a natural 

 and artificial cold f 



177. The experiments of Mr Hunter farther 

 prove, that the temperature of most of the foregoing 

 animals not only falls rapidly in a colder medium, 

 but that it rises more quickly in a warmer one than 

 that of those which possess a higher standard tempe- 

 rature. In the stomach of a frog, the thermometer 

 rose from 45 to 49 : the animal was then placed 

 in an atmosphere made warm by heated water, 

 where it remained for twenty minutes, and, upon in- 

 troducing the thermometer again into the stomach, 

 the mercury rose to 64 J. A healthy viper was put 

 into an atmosphere of 108, and, in seven minutes, 

 the heat of the animal, both in the stomach and 



* Observations on Animal (Economy, p. 104'. 

 f Ibid. p. 89, 90. t Ibid. p. 90. 



