2$* O F S L E E P. SECT. XVIII. 16* 



creafed, fo the heat of the fyfiem is gradually in- 

 creafed, and the extremities of feeble people, which 

 had been cold during the day, become warm. Tilt 

 towards morning many people become fo warm, as 

 to find it neceflary to throw oft forae of their bed- 

 clothes, as foon as they awake ; and in others 

 fweats are fo liable to occur towards morning during 

 vheir 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 affects any part of the body, a torpor 

 of that part is more effectually produced, as when a 

 cold blaft of air through a key-hole or cafement falls 

 upon a perfon in a warm room. In thofe cafes the 

 affected part pofieffes lefs irritability in refpect to heat, 

 from its having previoufly been expofed to a greater 

 flimulus of heat, as in the warm room, or during 

 fleep ; and hence, when the ftimuhis of heat is di-, 

 minifhed, a torpor is liable to enfue ; that is, we 

 take cold. Hence people who fleep in the open air, 

 generally feel chilly both at the approach of fleep, 

 and on their awaking ; and hence many people are 

 perpetually fubject to catarrhs if they freep in a 

 lefs warn* head-drefs, than that which they wear in 

 the day. . 



1 6. Not only the fenforial powers of irritation and 

 of fenfation, but that of affbciation alfo appear to acl: 

 with greater vigour during thefufpenfion of volition: 

 in fleep. It will be fhewn in another place, that the 

 gout generally^ attacks the liver, and that afterwards 

 an inflammation of the ball of the great toe com- 

 menccs by affociation, and that of the liver ceafes. 

 Now as this change or metaftafis of the activity 

 of the fyftem generally commences in fleep, it fol- 

 lows, that the.fe aflbeiations of motion exift with 



greater 



