402 Notices of Scientific Works. [July, 



body and HmLs, an open eye and dilated pupil ; but obscure \asion 

 or blindness, dulness of hearing or deafness, and withal, after 

 relapsing into sleep and complete awakening, no recollection of the 

 purposes or occurrences of the somnambuhstic state ; " * and this con- 

 dition he accounts for by the theory that one set of arteries which 

 supj^ly a certain part of the brain are fully dilated, whilst another 

 set which supply the remaining portion of the brain are partially 

 closed, sleep being " due to contraction of all the arteries of the 

 brain, and somnambuhsm to that of the carotids only." t 



If the closure of certain arteries, which supply the brain with 

 blood, brought about by nervous influence, is conducive to sleep, it 

 follows that any cause which diminishes the quantity of blood 

 circulating in the brain will have a similar effect ; and the author 

 says that " many examples of sleep arising upon the hgature, 

 compression, or obstruction of the carotid trunks, enable us to 

 conclude decisively that the diminution of the arterial current in 

 the brain which occurs at the instant of sleep is no mere concomi- 

 tant occurrence, but its actual cause." Ho might have adduced 

 evidence of a kind more familiar to the general reader. Putting the 

 feet in hot water causes an increased circulation in those members, 

 and by drawing the blood from the brain, mduces sleep. Sometimes 

 a reaction ensues during the night ; the feet become cold, the blood 

 sets in the direction of the brain, and the patient awakes. On the 

 other hand, the hydropathic treatment is in this respect more 

 effective. When the feet are put into cold water and well rubbed, 

 both whilst they are in the water and subsequently, an improved 

 circulation is maintained throughout the night, and a sound 

 unbroken sleep is the result. 



Again, any person who finds it difficult to obtain rest, may 

 probably succeed by lying down upon his back and doubhng his 

 pillow so that it fits into the back of his neck. The circulation 

 is thus evidently impeded, for wo have often found a drowsiness to 

 supervene almost immediately on assuming this attitude. 



Wliilst the author thus describes the proximate causes of sleep 

 under ordinary circumstances, he takes care to mention that the 

 state may be banished by the exercise of the will ; and that the will 

 may also produce it. But this is nothing more nor less than sajdng 

 that the mind is the active agent, and the brain the passive instru- 

 ment ; and exactly here it is that we believe his work to be so sug- 

 gestive in regard to man's psychical powers. That in the long run 

 " mens Sana in corpore sano " is true, and that the exercise of 

 active mental power requires a sound and well-ordered physical 

 frame, no one vnW for a moment deny. But just as the most 

 powerful physical exertions are samctimes successfully put forth by 



* P. 49. t Pp. 52-55. 



