46* THEORY OF FEVER. Sup. I. 7. 4. 



rife of the thermometer in both cafes continues the fame. This 

 fact may be known by boiling an egg in water, the white of 

 which coagulates in much lefs timej if the water boils vehement- 

 ly, than if it boils moderately, though the fenfible heat of the 

 water is the fame in both cafes. 



Another caufe, which induces the cutaneous capillaries to re- 

 new their actions fooner than the heart and arteries after im- 

 rnerfion in the cold bath, is, that their torpor was occafioned by 

 defect of irritation : whereas that of the heart and arteries was 

 occafioned by defect: of aflbciation ; which defect of aflbciation 

 was owing to the decreafed actions of the capillaries, and is now 

 again excited by their renewed action ; which excitement muft 

 therefore be fubfequent to that increafed action of the capilla- 

 ries ; and in confequence the increafed action of the heart and 

 arteries at the commencement of the hot fit of fome fevers is 

 fubfequent to the increafed action of the cutaneous capillaries. 

 There is, however, in this cafe an accumulation of the fenforial 

 power of aflbciation in the heart and arteries, which muft con- 

 tribute to increafe their orgafm in the hot fit, as well as the in- 

 creafed excitement of it by the increafed action of the capillaries. 



4. Now this increafed action of the fyftem, during the hot 

 fit, by exhaufting the fenforial powers of irritation and aflbcia- 

 tion, contributes to induce a renewal of the cold paroxyfm ; as 

 the accumulation of thofe fenforial powers in the cold fit pro- 

 duces the increafed actions of the hot fit ; which two ftates of 

 the fyftem reciprocally induce each other by a kind of libration, 

 or a plus and minus, of the fenforial powers of irritation and 

 aflbciation. 



If the exhauftion of fenforial power during the hot fit of fe- 

 ver only reduces the quantity of irritability and allowability to 

 its natural ftandard^ the fever is cured, not being liable to re- 

 turn. If the quantity of thefe fenforial powers be reduced only 

 io much, as not to produce a fecond cold fit during the prefent 

 quantity of external ftimuli or influences ; yet it may be fo far 

 reduced, that a very fmall fubtraction of ftimulus, or of influ- 

 ence, may again induce a cold fit ; fuch as the coldnefs of the 

 night-air, or the diminution of folar or lunar gravitation, as in 

 intermittent fevers. 



5. Another caufe of the renovation of the cold fits of fever 

 is lrom fome parts of the fyftem not having completely recov- 

 ered from the former cold paroxyfm ; as happens to the fpleen, 

 liver, or other internal vifcus ; which fometimes remains tumid, 

 and either occafions a return of the cold fit by direct fympathy 

 with other parts of the body, or by its own want of action cauf- 

 es a diminution of the genial quantity of hea.t, and thus facili- 

 tates 



