CLASS T. t. 2. 1. OF IRRITATION., 1 3 



ORDO I. 



Increased Irritation. 

 GENUS II. 



With increased Actions of the Secerning System. 



THESE are always attended with increase of partial or of gene- 

 ral heat; for the secreted fluids are not simply separated from 

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

 exist as such in the blood-vessels. But all new combinations give 

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

 is always increased in proportion to the secretion of the part 

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

 less there is reason to believe, that as we have a sense purposely 

 to distinguish the presence of greater or less quantities of heat, 

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

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

 secrete the sensorial power, which would more easily account, for 

 the instantaneous production of the blush of shame, and of an- 

 ger. This subject deserves further investigation. 



SPECIES. 



1. Calorfebrilis. The heat in fevers arises from the increase 

 of some secretion, either of the natural fluids, as in irrita- 

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

 vessels, as in inflammatory fevers. The pain of heat is a conse- 

 quence of the increased extension or contraction of the fibres 

 exposed to so great a stimulus. See Class I. 1. 5. 6. 



2. Ruborfebrilis. Febrile redness. When the cold fit of fe- 

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

 come strong as well as quick from the increase of their irritabili- 

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

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

 pillaries, quicker than the extremities of the veins can absorb 

 and return it to the heart. Hence the pulse at the wrist becomes 

 full, as well as quick and strong, and the skin glows with arte- 

 rial blood, and the veins become empty and less visible. 



In elderly people the force of the heart and arteries becomes 

 less, while the absorbent power of the veins remains the same; 

 whence the capillary vessels part with the blood, as soon as it is 

 received, and the skin in consequence becomes paler; it is also 



