Conjechires on the proximate Cause of Sleep. 325 



limited portions of the brain, were awake witli the organs of 

 sense, the obvious and natural consequence is actually one of very 

 common occurrence. The active organs continue to think ; but 

 their thoughts do not ap})ear to be dreams, because our com- 

 munication with the external world, by means of our senses, pre- 

 vents this ph?enomenon ; but at the same time we are sensible 

 that we are, to use a common expression, half awake and half 

 asleep ; and there are few individuals who have not frequently 

 indulged themselves in the luxury of observing the gradual de- 

 parture of their slumbers, and the renewal' of their active and 

 proper existence. Yet, possibly, if the organ of a single sense is 

 awake, — as for example, that of hearing or feeling, — its effects 

 may not be altogether complete, but so far merely as to satisfy us 

 of the illusory nature of our hiternal perceptions; and thus we are 

 enabled to account for the extraordinary circumstance of dream- 

 ing that we are dreaming. 



These several predicaments, therefore, present no less than 

 geven different states of sleeping and waking : — 1. When the e7i~ 

 tire hrain and nervous system are buried in sleep; and then there 

 is a total exemption from dreaming. 



2. When some of the mental organs are awake, and all the 

 senses are asleep ; then dreams occur, and seem to be realities- 

 If among these busy organs should be one or two, whose pecu- 

 liar powers and affections will readily occur to the admirers of 

 the organic theory, their disturbance, whether occasioned by dis- 

 order of the digestive functions, or any other cause, will suffi- 

 ciently account for uneasy dreams, frightful visions, and opjMes- 

 sive night-mares. 



3. When the above-mentioned conditions exist, and the nerves 

 of voluntary motion are also in a state of wakefulness, then may 

 occur the rare phenomenon of somnambulism. 



4. When one of the senses is awake with some of the menial 

 organs, then we may be conscious during our dream of its illu- 

 sory nature ; and if the nerves of voluntary motion concur, som- 

 nambulism may also accompany these circumstances. 



5. When some of the mental organs are asleep and two or 

 •more senses awake, then we can attend to external impressions, 

 and notice the gradual departure of our slumbers; a state in 

 which we consider ourselves neither awake nor asleep. 



6. When we are totally awake and in the full enjoyment of all 

 our faculties and powers, 



7. When under these circumstances vve are so intimatciv oc- 

 cupied by our mental operations, as that we do not attend ft the 

 impressions of external objects; and then our reverie deludes us 

 like a dream. 



Thus, as the process of assimilation ceases to operate, one por- 

 X 3 tion 



