48 THE MUSCLES 



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 building up takes place more actively. In this 

 way we are refreshed 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 with- 

 out sleep for many days without apparent injury. Frederick 

 the Great required only five hours of sleep daily, and 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 on 

 the gun-deck of their ships while in action. On the retreat 

 from Moscow, the French soldiers would fall asleep on the 

 march, and could only be aroused by the cry, " The Cossacks 

 are coming ! " Tortured persons are said to have slept upon 

 the rack in the intervals of their torture. In early life, while 

 engaged in a laborious country practice, the writer not unfre- 

 quently slept soundly on horseback. These instances, and 

 others, show the imperative demand which nature makes for 

 rest in sleep. 



33. Alcohol and Strength. Alcohol, a substance to be fully 

 described in our subsequent chapter on Food and Drink, merits 

 consideration at this point by reason of the mistaken views 

 held by many as to its beneficial effects upon the muscles, 



31. Amount of sleep for different persons ? Cases? Frederick the Great ? Bonaparte? 

 Instances of long deprivation of sleep ? 



32. Instances of sailors ? French soldiers ? During torture ? 



33. The former use of grog. 



