458 THEORY OF FEVER. Sup. 1. 6. 5. 



the fecerning fyftem, when the fenforial power of fenfation i» 

 added to that of irirtation, frequently produces inflammation, 

 which con fills in the fecretion of new fluids or new veffels. 

 Neverthelefs, if thefe disturbed actions be of the torpid kind, 

 the pain, which attends them, is feldorn productive of inflam- 

 mation, as in hemicrania ; but is liable to excite voluntary ac- 

 tions, and thus to expend much fenforial power, as in the fhud- 

 dering in cold fits of fever, or in convulfions *, or laltly the pain 

 itfelf, which attends torpid actions, is liable to expend or ex- 

 hauft much fenforial power without producing any increafed 

 actions ; whence the lowpulfe, and cold extremities, which ufu- 

 ally attend hemicrania j and hence when inert, or inactive fen- 

 fation attends one link of aflbciated action, the fucceeding link 

 is generally rendered torpid, as a coldnefs of the cheek attends 

 tooth-ach. 



5. A fifth important circle of irritative motions is that of the 

 fanguiferous fyftem, in which the capillary veflels are to be in- 

 cluded, which unite the arterial and venous fyftems, both pul- 

 monary and aortal. The difturbed action of this fyftem of the 

 heart and arteries, and capillaries, conftitutes fimple fever ; to 

 which may be added, that the fecerning and abibrbent veflels 

 appending to the capillaries, and the bibulous mouths of the 

 veins, are in fome meaiure at the fame time generally affected. 



6. Now, though the links of each of thefe circles of irritative 

 motions are more ftrictly aflbciated together, yet are they in 

 Greater or lefs degree aflbciated or catenated with each other by 

 direct or reverfe fympathy. Thus the ficknefs, or inverted irri- 

 tative motions of the ftomach, are aflbciated or catenated with 

 the difturbed irritative ideas, or fenfual motions, in vertigo •, as 

 in fea-ficknefs. This ficknefs of the ftomach is alfo aflbciated 

 or catenated with the torpor of the heart and arteries by direct 

 fympathy, and with the capillaries and abforbents by reverfe 

 fympathy ; and are thus all of them liable occafionally to be dif- 

 turbed, when one of them is difeafed ; and conftitute the great 

 variety of the kinds or fymptoms of fevers. 



VII. Alternation of the cold and hot Fits. 



1. When any caufe occurs, which diminifhes to a certain de- 

 gree the fupply of fenforial power in refpect to the whole fyf- 

 tem *, as fuppcfe a temporary inexertion of the brain -, what 

 happens ? Firft, thofe motions are exerted with lefs euergy, 

 which are not immediately neceflary to life, as the locomotive 

 mufcles *, and thofe ideas, which are generally excited by voli- 

 tion j at the fame time this deficiency of voluntary motion is 



difFefent 



