1 6 DISEASES CLASS!, i.: 



veffels, which are generally cooler than the internal parts 

 fyftem, excites them into greater action ; and pleafurable fenfa- 

 tion is the confequence of thefe increafed actions of the vefiels 

 of the (kin. From confiderrng all thefe circumftances, it ap- 

 pears that it is not the evacuation by fweats, but the continued 

 ftimulus, which caufes and fupports thole fweats, which is fer- 

 viceable in preventing the returns of fever-fits. And that fweats 

 too long continued, or induced by too great ftimulus of warmth, 

 clothes, or medicines, greatly injure the patient by increafmg in- 

 flammation, or by exhaufting the fenforial power. See Glafs I. 

 I. 2. 14. 



Secondly, The fweats produced by exercife or labour are of 

 the warm kind ; as they originate from the increafed action of 

 the capillaries of the (kin, owing to their being more powerfully 

 itimulated by the greater velocity of the blood, and by a greater 

 quantity of it paffing through them- in a given time For the 

 blood during violent exercife is carried forwards by the action 

 of the mufcles fafter in the arteries, than it can be taken up by 

 the veins ; as appears by the rednefs of the fkin. And from 

 the confequent fweats, it is evinced, that the fecretory veiTels of 

 the fkin during exercife pour out the perfpirable matter fafter, 

 than the mouths of the abforbent veifels can drink it up. Which 

 mouths are riot expofed to the increafed mufcular action, or to 

 the ftimulus of the increafed velocity and quantity of the blood* 

 but to the cool air. 



Thirdly^ the increafed fecretion of perfpirable matter occafion- 

 ed by the ftimulus of exteral heat belongs likewife to this place 5 

 as it is caufed by the increafed motions of the capillary veffels 5 

 which thus feparate from the blood more perfpirable matter, 

 than the mouths of their correfpondent abforbent veffels can take 

 up ; though thefe alfo are ftimulated by external heat into more 

 energetic action. If the air be ftationary, as in a fmall room, 

 or bed with clofed curtains, the fweat {lands in drops on the fkin 

 for want of a quicker exhalation proportioned to the quicker fe* 

 cretion. 



A fourth variety of warm perfpiration is that occafioned by 

 llimulating drugs, of which opitfm and alcohol are the moft 

 powerful ; and next to thefe the fpices, volatile alkali, and neu- 

 tral falts, efpecially fea-falt ; that much of the aqueous part of 

 the blood is diffipated by the ufe of thefe drugs, is evinced by the 

 great thirft, which occurs a few hours after the ufe of them. Sea 

 Art. III. 2. i. 



We may from hence underftand, that the increafe of this 

 fecretion of perfpirable matter by artificial means, muft be fol- 

 lowed by debility and emaciation. When this is done by taking 



much 



