34 SECERNENTIA. ART. IH. 2. i. 5. 



fweat is fecreted in abundance, its evaporation cannot carry off 

 the exuberant heat, like the vapour of boiling water ; becaufe a 

 great part of it is wiped off, or abforbed by the bed-clothes ; or 

 the air about the patient is not changed fufficiently often, as it 

 becomes faturated with the perfpirable matter. And hence it 

 is probable, that'the wafte of perfpirable matter is as great, or 

 greater, when the (kin is hot and dry, as when it (lands in 

 drops on the fkin ; as appears from the inextinguifhable 

 third 



Hence Dr. Alexander found, that when the heat of the body 

 was greater than 1 08, nothing produced fweats but repeated 

 draughts of cold water ; and of warm fluids, when the heat 

 was much below that degree. And that cold water which pro- 

 cured fweats inftantaneoufly when the heat was above 108, 

 flopped them as certainly when it was below that heat ; and 

 thar flannels, wrung out of warm water and wrapped round the 

 legs and thighs, were then moil certainly productive of fweats. 



5 The diaphoretics are all faid to fucceed much better, if given 

 early in the morning, about an hour before fun-rife, than at any 

 other time ; which is owing to the great excitability of every 

 part of the fyflem after the fenforial power has been accumu- 

 lated during fleep. In thofe, who have heftic fever, or the fe- 

 bricula, or nocturnal fever of debility, the morning fwears are 

 owing to the decline of the fever-fit, as explained in Sel. XXXII. 

 p In fome of thefe patients the fweat does not occur till they 

 awake j becaufe then the fyftem is ftill more excitable than du- 

 ring fleep, becaufe the afliftance of the voluntary power in 

 refpiration facilitates the general circulation. See Clafs I. 

 2. I. 3 . 



6. It muft be obferved, that the fkin is very dry and hard 

 to the touch, where the abforbents, which open on its furface, do 

 not aft ; as in fome dropfies, and other difeafes attended with 

 great thir ft. This drynefs, and fhrivelled appearance, and rough- 

 nefs, are owing to the mouths of the abforbents being empty of 

 their accuftomed fluid, and is diftinguifhabie from the drynefs 

 of the fkin above mentioned in the hot fits of fever, by its not 

 being attended with heat. 



As the heat of the fkin in the ufual temperature of the air 

 always evinces an increafed perfpiration, whether vifible or not, 

 the heat being produced along with the increafe of fecretion ; 

 it follows, that a defeft of perfpiration can only exift, when the 

 fkin is cold. 



7. Volatile alkali is a very powerful diaphoretic, and partic- 

 ularly if exhibited in wine- whey \ twenty drops of fpirit of 

 hartihorn every half hour in half a pint of wine- whey, if the pa- 

 tient 



