446 THEORY OF FEVER. SUP. I. 1. 2. 



for a minute, these capillary vessels and their glands become 

 torpid or quiescent, owing to the eduction of the stimulus of heat. 

 The skin then becomes pale, because no blood passes through the 

 external capillaries; and appears shrunk, because their sides are 

 collapsed from inactivity, not contracted by spasrn; the roots of 

 the hair are left prominent from the seceding or subsiding of the 

 skin around them; and the pain of coldness is produced. 



In this situation, if the usual degree of warmth be applied, 

 these vessels regain their activity; and having now become more 

 irritable from an accumulation of the sensorial power of irritation 

 during their quiescence, a greater exertion of them follows, with 

 an increased glow of the skin, and another kind of pain, which 

 is called the hot-ach; but no fever, properly so called, is yet pro- 

 duced; as this effect is not universal, nor permanent, nor recur- 

 rent. 



2. If a greater part of the cutaneous capillaries with their 

 mucous and perspirative glands be exposed for a longer time to 

 cold, the torpor or quiescence becomes extended by direct sym- 

 pathy to the heart and arteries; which is known by the weak- 

 ness, and consequent frequency, of the pulse in cold fits of fever. 



This requires to be further explained. The movements of the 

 heart and arteries, and the whole of the circulatory vessels, are in 

 general excited into action by the two sensorial powers of irri- 

 tation, and of association. The former is excited by stimulus, 

 the latter by the previous actions of a part of the vital circle of 

 motions. In the above situation, the capillaries act weakly from 

 defect of irritation, w^hich is caused by deficient stimulus of heat; 

 but the heart and arteries act weakly from defect of association, 

 which is owing to the weak action of the capillaries; which does 

 not now excite the sensorial power of association into action with 

 sufficient energy. 



After a time, either by the application of warmth, or by the 

 increase of their irritability owing to the accumulation of the 

 sensorial power of irritation, during their previous quiescence, 

 the capillary vessels and glands act with greater energy than na- 

 tural; whence the red colour and heat of the skin. The heart 

 and arteries acquire a greater strength of pulsation, and continue 

 the frequency of it, owing to the accumulation of the sensorial 

 power of association during their previous torpor, and their con- 

 sequent greater associability; which is now also more strongly 

 excited by the increased actions of the capillaries. And thus a 

 fit of simple fever is produced, which is termed febris irrita- 

 tiva;^id consists of a torpor of the cutaneous capillaries with 

 their mucous and perspirable glands, accompanied with a torpor 



