944 INFLUENCE OF SLEEP ON 



seven hours sleep, the fluid exhaled from the skin 

 of a healthy man was about double what was lost 

 in the same time while he was awake. (Med. 

 Stat. Sect. 4.) 



But as less caloric is obtained by respiration 

 during sleep than when we are awake ; if the body 

 be not well covered, it is more easily chilled, and 

 the circulation depressed, than during exercise. 

 Hence it is, that when exhausted by previous exer- 

 tion, the caloric obtained by breathing is still more 

 rapidly abstracted by exposure to cold and damp 

 night air during sleep, than it is replaced, by 

 which the body is predisposed to a chill, which 

 ushers in all the different forms of fever and 

 other constitutional maladies. M. Quetelet states 

 in his recent statistical work on man, that the 

 number of inspirations are diminished during 

 sleep, in the ratio of 6 to 7 when awake ; and 

 the pulsations at the wrist, in the ratio of 3 to 4 

 per minute : that among 300 individuals, at dif- 

 ferent ages, the extreme values were as repre- 

 sented in the following table : (see p. 71.) 



Inspirations. Pulsations. 



At birth 44 136 



Five years . . , 26 88 



15 to 20 20 69-5 



20 to 25 18-7 69-7 



25 to 30 16 71 



30 to 50 18-1 70 



But that the diminished frequency of the heart's 

 action during sleep is owing to the cessation of 



