Sup. I. i<5. 7. THEORY OF FEVER. 505 



fenforial power of fenfation, whence exteniive inflammation or 

 mortification ; but when the ftomach and confequently the heart 

 and arteries continue their torpidity of action ; as in confluent 

 imall-pox, and fatal fcarlatina ; this conftitutes fenfitive inirri- 

 tative fever, or typhus gravior. 



But when the ftomach is fecondarily affected, if the fenforial 

 power of fenfation is excited, as in pleurify or peripneumony, 

 the actions of the heart and arteries are violently increafed, and 

 of all the moving fyftem along with them. Thus the peripneu- 

 mony is generally induced by the patient refpiring very cold air, 

 and this efpecially after being long confined to warm air, or af- 

 ter being much fatigued and heated by exceffive labour or exer- 

 cife. For we can cover the fkin with more clothes, when we 

 feel ourfelves cold •, but the lungs not having the perception of 

 cold, we do not think of covering them, nor have the power to 

 cover them, if we defired it \ and the torpor thus produced is 

 greater, or of longer duration, in proportion to the previous ex- 

 penditure of fenforial power by heat or exercife. 



This torpor of the lungs affects the fkin with muddering, and 

 the ftomach is alio fecondarily affected ; next follows the violent 

 action of the lungs from the accumulation of the power of irri- 

 tation, and an inflammation of them follows this violent action. 

 While the ftomach recovers its activity by the increafe of the 

 excitement of the fenforial power of aflbciation, and along with 

 it the heart and arteries, and the whole moving fyftem. Hence 

 this inflammation occurs during the hot fit of fever, and no cold 

 fit fucceeds, becaufe the excefs of the fenforial power of fenfa- 

 tion prevents a fucceeding torpor. 



Thefe new motions of certain parts of the fyftem produce in- 

 creafed fecretions of nutritious or organic mucus, which forms 

 new vefTels ; thefe new veflels by their unufual motions produce 

 new kinds of fluids ; which are termed contagious, becaufe they 

 have the power, when introduced into a healthy body, of pro- 

 ducing fimilar actions and effects, with or without fever, as in 

 the fmall-pox and meafles, or in the itch and venereal difeafe. 



If any of thefe contagious matters affect the ftomach with tor- 

 por either by their ftimulus immediately applied, or by its fym- 

 pathy with the parts firft difeafed, a fever is produced with fick- 

 nefs and wan£ of appetite ; as in fmall-pox, and fcarlatina. If 

 the ftomach is not affected by contagious matter, no fever fuc- 

 ceeds, as in itch, tinea, fyphilis. 



All thefe contagious matters are conceived to be harmlefs, till 



they have been expoted to the air, either openly or through a 



.moid membrane •, from which they are believed to acquire oxy- 



gcnsy and thence to become fome kinds of animal acids- As 



Vol. IL R r r the 



