DREAMING. 613 



of the brain is the same as that of voluntary muscles. If these 

 are laid bare and freely stimulated, they at length cease to con- 

 tract ; after a little repose, they obey a stimulus again. The 

 brain may be kept awake by strong exciting causes long after it 

 would have sunk into inactivity ; but at length no stimulus will 

 rouse it and sleep is inevitable. Exhausted soldiers sometimes 

 sleep as they march, or sink on the ground in deep slumber 

 am'"' 1 -*: the roar of cannon. Still more readily will the young. 

 ^ the battle of the Nile some boys fell asleep on deck 

 in the heat of that dreadful engagement. 7 



In sleep the function of the brain is suspended, and, if it is 

 perfect, there is no sensation, consciousness, thought, emotion, or 

 volition : but the degree of suspension is extremely various. In 

 ordinary sleep the mind is susceptible of sensations, and able, 

 if these are unpleasant, to make an effort to remove their causes ; 

 whether to remove the uneasiness of impeded circulation in 

 the lungs by breathing, or to draw away the hand when tickled, 

 or change our position, as some continually do in sleep. One 

 or more faculties is often active, and one idea associates with 

 it another, intellectual or moral, so that we dream ; but the ac- 

 tivity of the mind is partial, and, though we are able occasionally 

 even to reason correctly in our dreams* we are not sufficiently 



organs are completely inactive, the soul can have neifhef feelings nor ideas. 

 Deep and complete sleep is a temporary cessation of persdnality (moi)." (11. cc. 

 4fo. vol. ii. p. 454. 8vo. t. ii. p. 506. sq.) By soul Gall meant cerebral 

 power : but he wrote cautiously, as in Austria, Italy, and France, catholics 

 are not contented to base our hopes of a future life upon Scripture, but insist 

 on the existence of a soul to make Scripture probable. 



v Dr. Macnish. Blumenbach and Cabanis call sleep a function. The former 

 says, " Sleep is a completely periodical function, by which the intercourse of the 

 mind and body is suspended, and whose phenomena correspond, if any do, with 

 the supposition of a nervous fluid." To say intercourse of mind and body, and 

 not activity of brain and its dependences, the rest of the encephalo-spinal 

 system, and to say nervous fluid, is antiquated nonsense. Cabanis's words are, 

 " Sleep is not simply a passive state, but a peculiar function of the brain." The 

 answer to both these writers is, that " the cessation of a function cannot be a 

 function." How different is the language of Gall: "Sleep is merely in the 

 activity, the perfect repose of the brain in health. During this suspension of the 

 cerebral functions, the brain acquires new force, and, oh waking, its functions 

 take place readily." 1. c. 8vo. t. i. p. 210. 



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