CLASS Til. 2. 1. 12. OP VOLITION. 341 



cause of the accompanying fever, seems to be confirmed by ob- 

 serving, that if an increased expenditure of heat accompanies the 

 increased generation of it, (as when perspiration on the extremi- 

 ties or surface attends this kind of sleep) the frequent pulse and 

 flushed countenance do not occur, as I know by experiment. If, 

 during the feverish sleep already mentioned, I am awakened, and 

 my attention engaged powerfully, my pulse becomes almost im- 

 mediately slower, and the fever gradually subsides." 



From these observations of Dr. Currie it appears, that, while 

 in common sleep the actions of the heart, arteries, and capillaries, 

 are strengthened by the accumulation of sensorial power during 

 the suspension of voluntary action, and the pulse in consequence 

 becomes fuller and slower; in the feverish sleep above described, 

 the actions of the heart, arteries, and capillaries, are quickened 

 as well as strengthened by their consent with the increased ac- 

 tions of the stomach, as well as by the stimulus of the new chyle 

 introduced into the circulation. For the stomach, and all other 

 parts of the system, being more sensible and more irritable during 

 sleep, Sect. XVIII. 15. and probably more ready to act from as- 

 sociation, are now exerted with greater velocity as well as strength, 

 constituting a temporary fever of the sensitive irritated kind, re- 

 sembling the fever excited by wine in the beginning of intoxica- 

 tion; or in some people by a full meal in their waking hours. 

 Sect. XXXV. 1. 



On waking, this increased sensibility and irritability of the 

 system cease, by the renewed exertions of volition; in the same 

 manner as more violent exertions of volition destroy greater pains; 

 and the pulse in consequence subsides along with the increase of 

 heat; if more violent efforts of volition are exerted, the system be- 

 comes still less affected by sensation or irritation. Hence the 

 fever and vertigo of intoxication are lessened by intense thinking, 

 Sect. XXI. 8.; and insane people are known to bear the pain of 

 cold and hunger better than others, Sect. XXXIV. 2. 5.; and 

 lastly, if greater voluntary efforts exist, as in violent anger or vi- 

 olent exercise, the whole system is thrown into more energetic ac- 

 tion, and a voluntary fever is induced, as appears by the red skin, 

 quickened pulse, and increase of heat; whence dropsies and fe- 

 vers with debility are not unfrequently removed by insanity. 



Hence the exertion of the voluntary power in its natural de- 

 gree diminishes the increased sensibility, and irritability, and 

 probably the increased associabilitv, which occur during sleep; 

 and thus reduces the frequency of the pulse in the feverish sleep 

 after a full meal. In its more powerful state of exertion, it di- 

 minishes or destroys sensations and irritations, which are stronger 



