



Class I. i. 2. i. OF IRRITATION, 13 



QRDO I. 



Increased Irritation* 

 GENUS II. 



With Increofd Aclloni of the Secerning Zyfem. 



These are always attended with increafe of partial or of gen- 

 ,-al heat •, for the fecreted fluids are not (imply feparated from 

 the blood, but are new combinations ; as they did not previously 

 : as fuch in the blood veflels. But all new combinations p; : . T :e 

 out heat chemically ; hence the. origin of animal heat, which 

 ii always increafed in proportion to the fecretion cf the part 

 affected, or to the general quantity of the fecretions. Neverthe- 

 lefs there is reafon to believe, thai: as we ha,ve a fenfe purpofely 

 to diftinguifh the prefence of greater or iefs quantities of her 

 as mentioned in Sect. XIV. 6. lb we may have certain minute 

 glands for the fecretion of this fluid, as the brain is believed to 

 fecrete the ienfonal power, which would more eafilv account for 

 the inftantaneous production of the blufh of fhame, and of an- 

 ger. This fuhject deferves further inveftigatlon. 



SPECIES. 



r . Calor febrills. The heat in fevers arifes from the IncreaiV. 

 ©f fome fecretion, either of the natural fluids, as in irrita- 

 tive fevers ; or of new fluids, as in infectious fevers; or of new 

 vefTels, as in inflammatory fevers. The pain of heat is a confe- 

 quence of the increafed extenfion or contraction of the fibres 

 expofed to fo great a ftimulus. See Clafs I. i. 5. 6. 



2. Rubor febrills. Febrile rednefs. When the cold fit of fe- 

 ver terminates, and the puifations of the heart and arteries be- 

 come ftrong as well as quick from the increafe of their irritabili- 

 ty after their late quiefcence, the blood is impelled forwards in- 

 to the fine extremities of the arteries, and the anaftamofing ca- 

 pillaries, quicker than the extremities of the veins can abforb 

 and return it to the heart. Hence the puife at the wrilt becomes 

 full, as well as quick and ftrong, and the fkin glows with arte- 

 rial blood, and the veins become empty and lefs vifible. 



In elderly people the force of the heart and arteries becomes 

 lets, while the abforbent power of the veins remains the fame ; 

 whence the capillary veffels part with the blood, as forn as it is 

 received, and the fkin in confequence becomes paler ; it is alfo 



probable, 



