The Nervous System 229 



sleep. The pulsations of the heart and the respiratory 

 movements are less frequent. 1 



348. The Amount of Sleep required. No precise rule 

 can be laid down concerning the amount of sleep required. 

 It varies with age, occupation, temperament, and climate 

 to a certain extent. An infant spends the greater part of 

 its time in sound sleep. Adults of average age who work 

 hard with their hands or brain usually require at least 

 eight hours of sleep. 



Personal peculiarities, and perhaps habit to a great extent, 

 exert a marked influence. Throughout his long and active 

 life Frederick the Great never slept more than five or six 

 hours in the twenty-four. Napoleon slept but four hours 

 a day. On the other hand, some of the busiest brain 

 workers require at least eight or nine hours of sound sleep 

 every night. 



349. Practical Rules about Sleep. Children should not 

 be allowed to play boisterously just before bedtime, nor 

 should their minds be excited with weird goblin stories, or a 

 long time may pass before the wide-open eyes and agitated 

 nerves become composed to slumber. 



At all ages the last hour before sleep should, if possible, 

 be spent quietly, to smooth the way towards sound and 

 refreshing rest. Medicines should not be taken to induce 

 sleep except on the advice of a physician. 



1 Remarkable instances are cited to illustrate the imperative demand 

 for sleep. Cavalrymen and frontiersmen have slept soundly in the saddle 

 during the exhausting campaigns against the Indians. A case is reported 

 of a captain of a British frigate who fell asleep and remained so for two 

 hours beside one of the largest guns of his vessel, the gun being served 

 vigorously all the time. Whole companies of men have been known to 

 sleep while on the march during an arduous campaign. Gunner boys have 

 been known to fall asleep during the height of a naval battle, owing to the 

 fatigue occasioned by the arduous labor in carrying ammunition for the 

 gunner. 



