498 THE TREATMENT OF DISEASES. 



which attends, or should attend, our waking moments. The more active the mind 

 the greater the necessity for sleep, just as with a steamer, the greater the number of 

 revolutions its engines make the more imperative is the demand for fuel. 



Most people require seven, or eight hours' sleep out of the twenty-four, although 

 many get on very well with only five or six. Students working for examinations 

 often restrict themselves to four or five hours nightly for a few weeks, and then try 

 and make up for it by passing nine or ten hours in bed for three or four weeks after- 

 wards. No man can play such tricks with his health with impunity. 



The necessity for sleep is sometimes so great that no effort of the will can resist 

 it. Sentinels have been known to sleep on their posts, even 111 the face of the most 

 imminent danger. Active bodily exertion will not always suffice to ward off sleep. 

 Many men have been known to sleep on horseback during night marches. In some 

 of our long walking matches against time, the pedestrian has been known to sleep at 

 night, still keeping up his weaiy roand. During the battle of the Nile many of 

 the boys engaged in handing ammunition fell asleep, notwithstanding the noise and 

 confusion of the action, and the fear of punishment. It is said, too, that on the 

 retreat to Corunna whole battalions of infantry slept while in rapid march. 



" Blessings," exclaimed Sancho, " on him that first invented sleep ! It wraps a 

 man all round like a cloak." The deprivation of sleep is one of the greatest punish- 

 ments that can be inflicted. The following story, quoted on good authority, will 

 serve to illustrate this fact : " A Chinese merchant had been convicted of murdering 

 his wife, and was sentenced to die by being deprived of sleep. This painful mode 

 of death was carried into effect under the following circumstances : The condemned 

 was placed in prison under the care of three of the police guard, who relieved each 

 other every alternate hour, and who prevented the prisoner falling asleep night or 

 day. He thus lived nineteen days without enjoying any sleep. At the commence- 

 ment of the eighth day his sufferings were so intense that he implored the authorities 

 to grant him the blessed opportunity of being strangled, guillotined, burned to 

 death, drowned, garrotted, shot, quartered, blown up with gunpowder, or put to 

 death in any conceivable way their humanity or ferocity could invent." This will 

 give some idea of the horrors of death from want of sleep. Damiens, who 

 attempted the assassination of Louis XV. of France, and who was sentenced to be 

 torn to pieces by four horses, was for an hour and a half before his execution 

 subjected to the most infamous tortures, with red-hot pincers, melted lead, burning 

 sulphur, boiled oil, and other- diabolical contrivances, yet he slept on the rack, and it 

 was only by continually changing the mode of torture, so as to give a new sensation, 

 that he was kept awake. He complained just before his death that the deprivation 

 of sleep was the greatest of all his torments. Amongst the fearful iniquities of the 

 " ordeal " and " torture," the system of Mersiglio was highly commended. This 

 consisted in keeping the victim from sleep for forty hours ; upon which practice it 

 has been cynically remarked that a hundred martyrs exposed to it would become 

 confessors to a man. 



The immediate cause of sleep is believed to be a diminished supply of blood to 

 the brain, and this will serve to explain the influence of many conditions in the 

 production of sleep. Thus, for example, it has been shown that animals often fall 



