THK MI.'HCLKH. 



be devoted to the improvement of the mind; and when 

 mental, we should then recreate by means of physical 

 exercise. 



30. During sleep, all voluntary activity ceases, the rapid- 

 ity of the circulation and breathing diminishes, and the 

 temperature of the body falls one or two degrees. In con- 

 sequence, the body needs warmer coverings than during 

 the hours of wakefulness. During sleep, the body seems 

 wholly at rest, and the mind is also inactive, if we except 

 those involuntary mental wanderings which we call dreams* 

 Nevertheless a very active and important physical process 

 is going on. Nutrition, or the nourishing of the tissues, 

 now takes place. While the body is in action, the process 

 of pulling down predominates, but in sleep, that of build- 

 ing up takes place more actively. In this way we are re- 

 freshed each night, and prepared for the work and pleasures 

 of another day. If sleep is insufficient, the effects are seen 

 in the lassitude and weakness which follow. Wakefulness 

 is very frequently the forerunner of insanity, especially 

 among those who perform excessive mental labor. 



31. All persons do not require the same amount of sleep, 

 but the average of men need from seven to nine hours. 

 There are well-authenticated cases where individuals have 

 remained without sleep for many days without apparent 

 injury. Frederick the Great required only five hours of 

 sleep daily. Bonaparte could pass days with only a few 

 hours of rest. But this long continued absence of sleep is 

 attended with danger. After loss of sleep for a long period, 

 in some instances, stupor has come on so profoundly, that 

 there has been no awaking. 



32. There are instances related of sailors falling asleep 



30. Cessation of voluntary activity ? Temperature of the body ? Consequence ? 

 Body and mind daring sleep ? Nutrition ? Describe it. Consequence of inroffi- 

 ci'rrj' rten - 



31. Amount of sleep in different persons? Cages? Frederick the Great? 

 Bonaparte? Instance* of Jong deprivation of sleep ? 



32. Instance* of sailors ? French soldiers ? During torture 1 



