AND ANIMAL LIFE. 143 



CHAP. VI. 



The manner in which the System is adapted to the 

 influence of Cold. 



CLIII. THE facility with which we support 

 the varieties of seasons, or the extremes of dif- 

 ferent media, has, from the earliest records of 

 observations, been continually adverted to, and 

 has also been productive of many opinions. To 

 ascertain the laws which regulate the capabilities 

 of the system in withstanding the operation of 

 cold, is even yet a subject of great interest 

 and importance. Although modern science has 

 thrown considerable light on the influence of 

 certain agents, which more or less contribute to 

 explain the difficulties, yet it must be acknow- 

 ledged, that we have not hitherto possessed satis- 

 factory principles which apply to general effects 

 or ascend to general causes. 



CLIV. In treating of the powers of the system 

 in resisting the agency of cold, it is scarcely 

 necessary to state, that the present chapter is a 

 continuation of the principles previously brought 

 forward in the two preceding, viz. " On the dis- 

 tribution of the blood at different ages," and " On 

 the temperature of the body at different ages." 

 Whatever facts may on the present occasion be 



