Siip.I. 0.2. THEORY OF* FEVER. 473 



same manner as a cold skin on going into the cold bath induces 

 difficulty of breathing. Or the stomach may become affected 

 with torpor, by its sympathy with the lungs, as in the experi- 

 ments of Mr. Watt with hydrocarbonate gas; a few respirations 

 of which induced sickness, and even syncope. When the sto- 

 mach or skin is thus affected secondarily by association, an accu- 

 mulation of sensorial power occurs much sooner, than when these 

 parts become torpid in consequence of previous excess of stimu- 

 lus; and hence they sooner recover their accustomed action, and 

 the fever ceases. The particles of contagious matter thus 

 received by respiration, somewhat resemble in their effects the 

 acid gases from burning sulphur, or from charcoal; which, if 

 they do not instantly destroy, induce a fever, and the patient 

 slowly recovers. 



2. I was some years ago stooping down, to look which way 

 the water oozed from a morass, as a labourer opened it with a 

 spade, to detect the source of the spring, and inhaled a vapour 

 which occasioned an instant sense of suffocation. Immediately 

 recoiling, I believe I inhaled it but once; yet, a few hours after- 

 wards, in the cool of the evening, when I returned home rather 

 fatigued and hungry, a shivering and cold fit occurred, which was 

 followed by a hot one; and the whole disease began and termi- 

 nated in about twelve hours without return. In this case, the 

 power of fear, or of imagination, was not concerned; as I neither 

 thought of the bad air of a morass before I perceived it, nor ex- 

 pected a fever-fit till it occurred. 



In this case, the torpor commenced in the lungs, and, after a 

 few hours, by the addition of fatigue, and cold, and hunger, was 

 propagated, by direct sympathy, to the rest of the system. An 

 orgasm, or increased action of the whole system, was then in- 

 duced, by the accumulation of sensorial power of irritation in the 

 lungs, and of association in the other organs; and, when these 

 subsided, the disease ceased. It may be asked, could a torpor 

 of the capillaries of the air-vessels of the lungs be so suddenly 

 produced by great stimulation? It appears probable, that it 

 might, because great exertion of irritative motions may be in- 

 stantly produced without our perceiving them; that is, without 

 their being attended by sensation, both in the lungs and stomach; 

 and the organs may become torpid by the great expenditure of 

 the sensorial power of irritation in an instant of time; as para- 

 lysis frequently instantly follows too great an exertion of volun- 

 tary power. 



o. When the capillaries of the lungs act too violently, as in 

 some continued fevers; which is known by the heat of the breath, 

 and by the dryness of the tongue, especially of the middle part 



VOL. ii, 3 p 



