tlsLj.2. i. OF IRRITATION. T 3 



-ORDO I. 



Increafed Irritation. 



GENUS II. 

 With Increafed Afiipns of the Secerning Syfem. 



THESE are always attended with increafe of partial or of gen* 

 tral heat ; for the fecreted fluids are not (imply feparated from 

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

 exift asfuch in the blood veflels. But all new combinations give 

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

 is always inc^eafed in proportion to the fecretion of the part 

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

 lefs there is reaibn to believe, that as we have a fenfe purpofely 

 to diftinguilh the prefence of greater or lefs quantities of heat, 

 as mentioned in Seel. XIV. 6. fo we may have certain minute 

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

 fecrete the fenforial power, which would more eafily account for 

 the inftantaneous production of the blufh of (hame, and of an- 

 ger. This fubjeft deferves further investigation. 



SPECIES. 



1 . Color felr ills. The heat in fevers arifes from the mcreafc 

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

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

 veflels, 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. Ruborfebrilts. Febrile rednefs. When the cold fit of fe- 

 ver terminates, and the pulfations 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 t'he fine extremities of the arteries, and the anaftainofmg ca- 

 pillaries, quicker than the extremities of the veins can abforb 

 and return it to the heart. Hence the pulfe at the wriil becomes 

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

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



In elderly people the force of the heart and arteries becomes 

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

 whence the capillary veflels part with the blood, as foon as it is 

 Deceived, and the fkin in confequence becomes paler \ it is alfo 



probable, 



