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more rapidly performed, but, at the same time, with less 

 power. The young animals grow, secrete, and excrete more, 

 in proportion to their masses than the old. The results, 

 however, of these processes are of an inferior character, and 

 are evidently formed under a less powerful vital influence. 

 The tissues are soft, of a whiter colour, more charged with 

 water, and the result of their action, as is well illustrated in 

 the muscular fibre, is less effective. This lesser power of 

 action is attended with (as a result) a lesser production of 

 heat. Animal temperature is the resultant of three variables. 

 The size of the animal, the inverse influence of which has 

 been previously appreciated — the rapidity with which its 

 functions are performed, and the power with which they are 

 performed. The rapidity of function diminishes from birth. 

 The size of the animal, and the power of function, increase 

 from the same period. About the fourth year, the increased 

 power of function and size, in spite of diminished rapidity, 

 raises the temperature gradually to that of the adult, and 

 from this period to the sixteenth year above that of the 

 adult. From this period the temperature remains stationary 

 until the advance of age combines all these variables in 

 their diminishing heat-producing powers to reduce the 

 temperature. From what has been said, it will be seen how 

 necessary it is to clothe children warmly before the fifth 

 year. In France, from Duvillard's table, ^ of the human 

 race die before they attain the fifth year ; and the 

 comparison by Edwards and Villerme of the mortality 

 under that age of children in the north and south of that 

 country, from the great excess of deaths in the former part, 

 proves how much this difference is attributable to cold. 

 The power of functional action is different in different indi- 

 viduals, and on this depends difference of temperament, 

 from the lymphatic and nervous, to the sanguine and 

 bilious, in whom will be found proportionate differences in 

 their powers of generating heat and resisting cold. 



