Strp. I. 8. 10. THEORY OF FEVER. 469 



whole lunar period passes, before it recovers its due irritability 

 and consequent action. 



In similar manner, after a person has been confined in a very 

 warm room for some hours, the cutaneous capillaries, with their 

 secretory and absorbent vessels, become exhausted of their senso- 

 rial power of irritation by the too great violent exertions occa- 

 sioned by the unusual stimulus of heat; and in coming into a 

 colder atmosphere an inactivity of the cutaneous vessels exists at 

 first for sometime without accumulation of sensorial power; as 

 is shewn by the continuance of the pain of cold and the paleness; 

 but after a time both the pain of cold and paleness vanish, 

 which now indicates an accumulation of the sensorial power of 

 irritation, as less degrees of heat stimulate the system into due 

 action. 



In the same manner, after any one has been some time in the 

 summer sunshine, on coming into a dark cell he continues much 

 longer before he can clearly distinguish objects, than if his eyes 

 had only been previously exposed to the light of a cloudy day in 

 winter; because the sensorial power of irritation, and consequent 

 sensation, had in the first case been previously much expended 

 or exhausted; and therefore required a much longer time be- 

 fore it could be produced in the brain, or derived to the optic 

 nerves, in such quantity as to restore the deficiency, and to cause 

 an accumulation of it; whereas in the latter case no deficiency 

 had occurred. 



10. Thus the accumulation or deficiency of sensorial power 

 in a torpid organ, which had previously been accustomed to per- 

 petual action, depends on the manner in which it becomes tor- 

 pid; that is, whether by great previous stimulus, or great previ- 

 ous excitement of the power of association; or by defect of its 

 accustomed stimulus, or of its accustomed excitement of the 

 power of association. I n the former case the sensorial power is in 

 an exhausted state, and therefore is not likely to become so soon 

 accumulated, as after drunkenness, or exposure to great heat, or 

 to great light; in the latter a great accumulation of sensorial 

 power occurs, as after exposure to cold, or hunger, or darkness. 



Hence when the stomach continues torpid by previous vio- 

 lent stimulus, as in the exhibition of digitalis, no accumulation 

 of sensorial power of irritation supervenes; and in consequence 

 the motions of the heart and arteries, which are associated with 

 those of the stomach, become weak, and slow and intermittent, 

 from the defect of the excitement of the sensorial power of asso- 

 ciation. But what follows ? as the actions of the heart and ar- 

 teries arc lessened by the deficient action of the sensorial power 

 of association, and not |)y previous increased excitement of it; 



