GLASS III. 2. i. 12. OF VOLITION. 341 



caufe of the accompanying fever, fecms to be confirmed by ob- 

 frrvin^, that if an increafed expenditure of heat accompanies 

 ncreafed generation of it (as when perfpiration on the ex- 

 tremities or furface attends this kind of fleep) the frequent pulfe 

 and flufhed countenance do not occur, as I know by experi- 

 ment. If, during the feverifh fleep already mentioned, I am 

 awakened, and my attention engaged powerfully, my pulfe 

 becomes almoft immediately flower, and the fever gradually fub- 

 fides." 



From thefe obfervations of Dr. Currie it appears, that, while 

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

 are ftrengthened by the accumulation of fenforial power during 

 the fufpenfion of voluntary action, and the pulfe in confequence 

 becomes fuller and flower , in the feverifh fleep above defcrib- 

 ed the aclions of the heart, arteries, and capillaries, are quicken- 

 ed as well as ftrengthened by their confent with the increafed 

 actions of the ftomach, as well as by the ftimulus of the new 

 chyle introduced into the circulation. For the ftomach, and all 

 other parts of the fyftem, being more fenfible and more irritable 

 during fleep, Seel:. XVIII. 15. and probably more ready to aft 

 from aflbciation, are now exerted with greater velocity as well 

 as ftrength, conftituting a temporary fever of the fenfitive irri- 

 tated kind, refembling the fever excited by wine in the begin- 

 ning of intoxication ; or in fome people by a full meal in their 

 waking hours. Sect. XXXV. i. 



On waking, this increafed fenfibility and irritability of the 

 fyftem ceafes by the renewed exertions of volition ; in the fame 

 manner as more violent exertions of volition deftroy greater 

 pains ; and the pulfe in confequence fubfides along with the in- 

 creafe of heat ; if more violent efforts of volition are exerted, 

 the fyftem becomes ftill lefs affected by fenfation or irritation* 

 Hence the fever and vertigo of intoxication are leflened by in- 

 tenfe thinking, Seel. XXI. 8 ; and in fane people are known to 

 bear the pain of cold and hunger better than others, Seel:, 

 XXXIV. 2. ^ ; and laftly, if greater voluntary efforts exift, as 

 in violent anger or violent exercife, the whole fyftem is thrown 

 into more energetic action, and a voluntary fever is induced, as 

 appears by the red (kin, quickened pulfe, and increafe of heat ; 

 whence dropfies and fevers with debility are not unfrequently 

 removed by infanity. 



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

 gree diminifhes the increafed fenfibility, and irritability, and 

 probably the increafed aflbciability, which occur during fleep ; 

 and thus reduces the frequency of the pulfe in the feveiiih fleep 

 r a nil) meal. In its more powerful date of exertion, it di- 



miniihes 



