SECT. XII. 5. OF STIMULUS AND EXERTION. 95- 



creafed abforption of the pulmonary and cellular 

 lymphatics is produced, as is known by the in- 

 creafed abforption of the fluid depofired in them 

 in dropfical cafes. But thefe partial quiefcences of 

 fenibrial power are alfo fometimes attended with 

 other partial quiefcences, which fympathife with 

 them, as cold and pale extremities from hunger. 

 Thefe therefore are to be afcribed to the affociations 

 of fympathy explained in Sect, XXXV. and not to 

 the general accumulation of fenforiai power. 



2. A quantity of Rimulus lefs than natural, ap- 

 plied to fibres previoufly accuftomed to perpetual 

 ftimuius, is iucceeded by accumulation of fenforiai 

 power in the affected organ. The truth of this 

 proportion is evinced., becaufe a ftimuius lefs than 

 natural, if it be fomewhat greater than that above 

 mentioned, will excite the organ fo circumftanced 

 into violent activity. Thus on a frofty day with 

 wind, t^e face of a perfon expofed to the wind is 

 at firft pale and fhrunk ; but on turning the face 

 from the wind, it becomes foon of a glow with 

 waimth and flufliing. The glow of the fkin in 

 emerging from the cold-bath is owing to the fame 

 caufe. 



It does not appear, that an accumulation of fen- 

 foriai power above the natural quantity is acquired 

 by thofe mufcles, which are not fubject to perpe- 

 tual ftimuius, as the locomotive mufcles : thefe, 

 after the greateft fatigue, only acquire by reft their 

 ufual aptitude to motion ; whereas the vafcular 

 fyftem, as the heart and arteries, after a fliort qui- 

 efcence, are thrown into violent action by their na- 

 tural quantity of flimulus. 



Neverthelefs by this accumulation of fenforiai 

 power during the application of decreafed ftimuius, 

 and by the exhauftion of it during the action of in- 

 creafed ftimuius, it is wifely provided, that the ac- 

 tions of the vafcular mufcles and organs of fenfe 



are 



