SECT. XXXII. 3. 2. OF IRRITATION. 287 



face of the ikin, and on the internal furfaces of every cell or 

 interftice of the body ; then the expenfe of fenforial power in 

 the venous abforption, by which the blood is received from the 

 capillary veflels, or glands, where the arterial power ceafes, and 

 is drunk up, and returned to the heart ; next the expenfe of 

 fenforial power ufed by the mufcles of refpiration in their of- 

 fice of perpetually expanding the bronchia, or air-veflels, of the 

 lungs; and laftly in the unceafmg periftaltic motions of the 

 ftomach and whole fyftem of inteftines, and in all the fecre- 

 tions of bile, gaftric juice, mucus, perfpirable matter, and the 

 various excretions from the fyftem. If we confider the ceafe- 

 lefs expenfe of fenforial power thus perpetually employed, it 

 will appear to be much greater in a day than all the voluntary 

 exertions of our mufcles and organs of fenfe confume in a 

 week ; and all this without any fenfible fatigue ! Now, if but 

 a part of thefe vital motions are impeded, or totally (lopped for 

 but a (hort time, we gain an idea that there muft be a great ac- 

 cumulation of fenforial power ; as its production in thefe or- 

 gans, which are fubjedt to perpetual ativity, is continued dur- 

 ing their quiefcence, and is in confequence accumulated. 



While, on the contrary, where thofe vital organs adt too for- 

 cibly by increafe of ftimulus without a proportionally increafed 

 production of fenforial power in the brain, it is evident, that a 

 great deficiency of adlion, that is torpor, muft foon follow, as 

 in fevers ; whereas the locomotive mufcles, which aft only by 

 intervals, are neither liable to fo great accumulation of fenforial 

 power during their times of inactivity, nor to fo great an ex- 

 hauftion of it during their times of ation. 



Thus, on going into a very cold bath, fuppofe at 33 degrees 

 of heat on Fahrenheit's fcale, the adion of the fubcutaneous 

 capillaries, or glands, and of the mouths of the cutaneous ab- 

 forbents is diminifhed, or ceafes for a time. Hence lefs or no 

 blood pafles thefe capillaries, and paienefs fucceeds. But foon 

 after emerging from the bath, a more florid colour and a greater 

 degree of heat are generated on the (kin than was pofleffcd be- 

 fore immerfion ; for the capillary glands, after this quiefcent 

 ftate, occafioned by the want of ftimulus, become more irritable 

 than ufual to their natural ftimuli, owing to the accumulation of 

 fenforial power, and hence a greater quantity of blood is tranf- 

 mitted through them, and a greater fecretion of perfpirable 

 matter ; and, in confequence, a greater degree of heat fucceeds. 

 During the continuance in cold water the breath is cold, and 

 the at of refpiration quick and laborious ; which have gener- 

 ally been afcribed to the obflruftion of the circulating fluid by 

 a fpafm of the cutaneous veflels, and by a confequent accumu- 

 lation 



