454 THEORY OF FEVER. SUP. I. 4. 1. 



IV. Return of the Cold Fit. 



1. If the increased action of the cutaneous and pulmonary 

 capillaries, and of the heart and arteries, in febris irritativa, con- 

 tinues long and with violence, a proportional expenditure or ex- 

 haustion of sensorial power occurs; which by its tendency to in- 

 duce torpor of some part, or of the whole, brings on a return of 

 the cold fit. 



2. Another cause which contributes to induce torpor of the 

 whole system by the sympathy of its parts with each other, is 

 the remaining torpor of some viscus; which after the last cold 

 paroxysm had not recovered itself, as of the spleen, liver, kid- 

 neys, or of the stomach and intestines, or absorbent vessels, as 

 above mentioned. 



3. Other causes are the deficiency of the natural stimuli, as 

 hunger, thirst, and want of fresh air. Other causes are great 

 fatigue, want of rest, fear, grief, or anxiety of mind. And lastly, 

 the influence of external ethereal fluids, as the defect of exter- 

 nal heat, arid of solar or lunar gravitation. Of the latter the 

 return of the paroxysms of continued fevers about six o'clock in 

 the evening, when the solar gravitation is the least, affords an 

 example of the influence of it; and the usual periods of inter- 

 mittents, whether quotidian, tertian, or quartan, which so regu- 

 larly obey solar or lunar days, afford instances of the influence of 

 those luminaries on these kinds of fevers. 



4. If the tendency to torpor in some viscus is considerable, 

 this will be increased at the time, when the terrene gravitation 

 is greatest, as explained in the introduction to Class IV. 2. 4. 

 and may either produce a cold paroxysm of quotidian fever; or 

 it may not yet be sufficient in quantity for that purpose, but may 

 nevertheless become greater, and continue so till the next period 

 of the greatest terrene gravitation, and may then either produce 

 a paroxysm of tertian fever; or may still become greater, and 

 continue so till the next period of greatest terrene gravitation, 

 and then produce a paroxysm of quartan ague. And lastly, the 

 periodical times of these paroxysms may exceed, or fall short of, 

 the time of greatest diurnal terrene gravitation according to the 

 time of day, or period of the moon, in which the first fit began; 

 that is, whether the diurnal terrene gravitation was then in an 

 increasing or decreasing state. 



V. Sensation excited in Fever. 

 1. A curious observation is related by Dr. Fordyce in his 



