458 THEORY OF FEVEll. SUP. I. 6.5. 



the secerning system, when the sensorial power of sensation is 

 added to that of irritation, frequently produces inflammation, 

 which consists in the secretion of new fluids or new vessels. 

 Nevertheless, if these disturbed actions be of the torpid kind, the 

 pain, which attends them, is seldom productive of inflammation, 

 as in hemicrania; but is liable to excite voluntary actions, and 

 thus to expend much sensorial power, as in the shuddering in 

 cold fits of fever, or in convulsions; or lastly, the pain itself, which 

 attends torpid actions, is liable to expend or exhaust much senso- 

 rial power, without producing any increased actions; whence 

 the low pulse, and cold extremities, which usually attend hemi- 

 crania; and hence when inert, or inactive sensation attends one 

 link of associated actions, the succeeding link is generally ren- 

 dered torpid, as a coldness of the cheek attends tooth-ach. 



5. A fifth important circle of irritative motions is that of the 

 sanguiferous system, in which the capillary vessels are to be in- 

 cluded, which unite the arterial and venous systems, both pul- 

 monary and aortal. The disturbed action of this system of the 

 heart and arteries, and capillaries, constitutes simple fever; to 

 which may be added, that the secerning and absorbent vessels 

 appending to the capillaries, and the bibulous mouths of the veins, 

 are, in some measure, at the same time generally affected. 



6. Now, though the links of each of these circles of irritative 

 motions are more strictly associated together, yet they are in 

 greater or less degree associated or catenated with each other by 

 direct or reverse sympathy. Thus the sickness, or inverted irri- 

 tative motions of the stomach, are associated or catenated with 

 the disturbed irritative ideas, or sensual motions, in vertigo; as 

 in sea-sickness. This sickness of the stomach is also associated 

 or catenated with the torpor of the heart and arteries by direct 

 sympathy, and with the capillaries and absorbents by reverse- 

 sympathy; and are thus all of them liable occasionally to be dis- 

 turbed, when one of them is diseased; and constitute the great 

 variety of the kinds or symptoms of fevers. 



VII. ^Alternation of the cold and hot Fits. 



1. When any cause occurs, which diminishes to a certain de- 

 gree the supply of sensorial power in respect to the whole sys- 

 tem; as suppose a temporary inexertion of the brain; what 

 happens? First, those motions are exerted with less energy, 

 which are not immediately necessary to life, as the locomotive 

 muscles; and those ideas, which are generally excited by voli- 

 tion; at the same time, this deficiency of voluntary motion is 



