x6* OF SLEEP. Sect. XVIII. 16. 



r 



increafe of irritability to internal ftimuli, or of fen fibility, during 

 fleep muft occafion them to commence at this time. 



Debilitated people, who have been unfortunately accuftomed 

 to great ingurgitation of fpirituous potation, frequently part 

 with a great quantity of water during the night, but with not 

 more than lifual in the day-time. This is owing to a beginning 

 torpor c* the abforbent fyftem, and precedes anafarca, which 

 Commences in the day, but is cured in the night by the increafe 

 of the irritability of the abforbent fyftem during fleep, which 

 thus imbibes from the cellular membrane the fluids, which had. 

 been accumulated there during the day •, though it is poflible 

 the horizontal poiition of the body may contribute fomething to 



is purpofe, and alfo the greater irritability of fome branches 

 of the abforbCnt veflels, which open their mouths in the cells of 

 the celltftar membranej than that of other branches. 



As foon as a perfon begins to fleep, the irritability and fenfi- 

 biiity of il\G fyttem begin to increafe, owing to the fufpenlionof 

 volition and the exclusion of external ftimuli. Hence the ac- 

 tions of the veflels in obedience to internal ftimulation become 

 ftronger and more energetic, though lefs frequent in refpe£l to 

 number. And as many of the fecretions are increafed, fo the 

 heat of the fyftem is gradually increafed, and the extremities of 

 feeble people, which had been cold during the day, become 

 warm. Till towards morning many people become fo warm, as 

 to find it neceflary to throw off fome of their bed-clothes, as 

 foon as they awake ; and In others fweats are fo liable to occur 

 towards morning during their fleep. 



Thus thofe, who are not accuftomed to fleep in the open air, 

 are very liable to take cold, if they happen to fall afleep on a 

 garden bench, or in a carriage with the window open. For as 

 the fyftem is warmer during fleep, as above explained, if a cur- 

 rent of cold air a (Feels any part of the body, a torpor of that part 

 is more effectually produced, as when a cold blaft of air through 

 ■ key-hole or cafement falls upon a perfon in a warm room. In 

 thofe cafes the a fleeted part poflTefles lefs irritability in refpec"t to,, 

 heat, from its having previously been expofed to a greater ftim«- : 

 ulus of heat, as in the warm room, or during deep j and hence, 

 when the ftimulus of heat is diminifhed, a torpor is liable to en- 

 iue ; that is, we take cold. Hence people who fleep in the 

 open air, generally feel chilly both at the approach of fleep, and 

 or: feheif av aking ; and hence many people are perpetually fub- 



£1 to catarrh, it they fleep in a lei's warm head-drefs, than that- 

 hey wear in the day. 

 >. wot only the fenforial powers of irritation and of fenfa* 



.•n, but that of afl ion alfo appear to act with greater vig~ 



our 



