344 



HITCHCOCK'S ANATOMY 



613. Inducements to Sleep— Sleep sometimes under 

 the Control of the Will. — Ordinarily darkness and si- 

 lence promote sleep ; but if a person once becomes habituated 

 to noise during slumber — if it be a continuous one — he can 

 not sleep well without it. Thus persons living in the vicinity 

 of forges and noisy mills can not readily sleep elsewhere. And 

 a monotonous repetition of sounds is a most favorable provo- 

 cative to sleep, the cause of which is that other impressions 

 can not so readily be made on the mind, and thus the sleeper 

 is less easily roused. A dull reader on a dull subject has a 

 most ready effect in producing sleep, as well as the sound of 

 a distant waterfall, or the rustling of leaves in a forest. Rub- 

 bing many parts of the skin, or combing the hair by another 

 person, will often cause drowsiness, and sometimes sleep. 

 Again a person can sometimes put himself to sleep, if restless, 

 by a monotonous intellectual effort, such as the rehearsal of a 

 Latin paradigm, or counting the rain-drops, as they fall from 

 the eave trough into the spout. 



614. Effect of Habit on Sleep.— The effect of habit is 

 powerful in producing sleep. Let one be accustomed to retire 

 early — in accordance with nature — and sleepiness comes at 

 the usual hour for retiring ; but if a person for a series of 

 years is in the habit of sleeping the latter part of the night 

 and early in the morning, it is almost impossible for him to 

 sleep early in the night. Those persons who, like sailors, 

 soldiers, and watchers, are obliged to catch sleep when they 

 can get it, and then only in small amounts at a time, sleep 

 with but little difficulty when the opportunity presents itself. 

 Captain Barclay, who walked one thousand miles in as many 

 consecutive hours, had such a power over himself, that he was 

 asleep the moment he lay down. Some physicians have the 

 same power. 



613. What are the common inducements to sleep? Do any persons ever require a 

 noise, in order to sleep soundly ? What effect does rubbing or chafing certain parts of 

 the body have upon sleep? Can sleep ever be brought about by an action of the will? 

 How ? 614. What effect has habit upon producing sleep ? Mention the caae of Captain 

 Barclay. 



