822 OF THE FUNCTIONS OF THE NERVOUS SYSTEM. 



tion of sleep so light, that a question asked restores consciousness enough for 

 momentary understanding and reply; and it is an old trick to bring sleepers 

 into this state, by putting the hand into cold water, or producing some other 

 sensation, not so active as to awaken, but sufficient to draw the mind from a 

 more profound to a lighter slumber. This may be often repeated, sleep still 

 going on; but make the sound louder and more sudden, and complete waking 

 at once ensues. The same with other sensations. Let the sleeper be gently 

 touched, and he shows sensibility, if at all, by some slight muscular move- 

 ment. A ruder touch excites more disturbance and motion, and probably 

 changes the current of dreaming ; yet sleep will go on ; and it often requires a 

 rough shaking, particularly in young persons, before full wakefulness can be 

 obtained." * * * "It is certain that the faculties of sensibility and volition are 

 often unequally awakened from sleep. The case may be stated, familiar to 

 many, of a person sleeping in an upright posture, with the head falling over 

 the breast ; in whom sensibility is suddenly aroused by some external impres- 

 sion, but who is unable, for a certain time, to raise his head, though the sensa- 

 tion produced by this delay of voluntary action is singularly distressing." These 

 various cases, it is justly remarked by Dr. Holland, 1 depending severally on the 

 intensity of sleep, and on the kind and degree of the external exciting causes, 

 will be found to explain many of those so-called Mesmeric phenomena which 

 are offered to us under a widely different interpretation. And it may be here 

 remarked, that among those intermediate states between sleep and waking, which 

 either occur spontaneously, or can be induced in numerous individuals by very 

 simple processes ( 825, 827), there are several which exhibit peculiarities that 

 are not in themselves in the least degree less remarkable than are those which 

 are regarded with so much wonder by the uninformed observer, when induced 

 by the asserted Mesmeric influence, and paraded as specimens of its powers (see 

 845, note). 



843. It is unquestionable that the supervention of Sleep may be promoted by 

 the strong previous expectation of it ; and this is true, not merely of ordinary 

 sleep, but of the states of artificial Reverie and Somnambulism formerly de- 

 scribed. Ever} T one knows the influence of habit, not only in regard to "time," 

 but also as to " place and circumstance," in predisposing to Sleep. Thus, the 

 celebrated pedestrian Capt. Barclay, when accomplishing his extraordinary feat 

 of walking 1000 miles in as many successive hours, obtained at last such a mastery 

 over himself that he fell asleep the instant he lay down. And the sleep of 

 soldiers, sailors, and others, who may be prevented from obtaining regular periods 

 of repose, but are obliged to take their rest at short intervals, may be almost 

 said to come at command ; nothing more being necessary to induce it than the 

 placing the body in an easy position, and the closure of the eyes. It is related 

 that the Abbe Faria, who acquired notoriety through his power of inducing 

 somnambulism, was accustomed merely to place his patient in an arm-chair, and 

 then, after telling him to shut his eyes and collect himself, to pronounce in a 

 strong voice and imperative tone the word " dormez," which was usually success- 

 ful. The Author has had frequent opportunities of satisfying himself that the 

 greater success which attends the " hypnotic" mode of inducing somnambulism 

 ( 827) in the hands of Mr. Braid, its discoverer, than in that of others, partly 

 lies in the mental condition of his subjects, who come to him for the most part 

 under the confident expectation of its production, and are further assured by a 

 man of very determined will that it cannot be resisted. 2 And it is one of the 

 most curious phenomena of the " biological" state ( 825), that, in many sub- 



1 See his excellent Chapter on " Sleep," from which the above extracts are taken, in his 

 " Medical Notes and Reflections," and his "Chapters on Mental Physiology." 



2 A very amusing instance in which Sleep, having been previously induced by the ordi- 

 nary "mesmeric" and then by the "hypnotic" processes, was brought on by the simple 



