CLASS II. i. 2. i. OF SENSATION. 163 



fli-y be eilecmed its eflential character, or the criterion of its 

 exiftence. The extenfion of the old veflels feems rather 3 con- 

 fequence than a caufe of the germination, or puli'ulation, of thefe 

 ncu ones; for the old veflels may be enlarged, and excited with 

 ial energy, without any production of new ones, as in the 

 bluih of (hame or of anger. 



When thefe new veiiels are formed, if they are not reabforbed 

 into the circulation, they fecrete a new fluid called purulent 

 matter ; which generally opens itfeif a paflage on the external 

 (kin, and produces an ulcer, which cither gradually h?ab, or 

 fpreads, and is the caufe of hectic fever ; or they fecrete conta- 

 gious matter, which has the property of exciting the fame kind 

 of inflammation, and -of producing the fame kind of contagious 

 matter, when inferted by inoculation into the fkin of other per- 

 fons. Thefe contagious matters form ulcers, which either heal 

 fpontaneoufly, or by art ; or continue to fpread, and dcftroy the 

 patient, by other kinds of hectic lever. 



In this genus there is an increafe of the fenforial power of ir- 

 ritation as well as of fenfation ; whence great arterial energy is 

 produced, and the pulfe becomes ftrong and full, as well as quick; 

 and the coats of the arteries feel hard under the finger, being 

 themfelves thickened and diftended by inflammation. The 

 blood drawn, efpecially at the fecond bleeding, is covered with 

 a tough fize ; which is probably the mucus from the inflamed 

 internal furface of the arteries, increafed in quantity, and more 

 coagulable than in its natural (late ; the thinner part being more 

 perfectly abforbed by the increafed action of the inflamed abforb- 

 ents. See Seel. XXXIII. 2. 2. This is rendered more prob- 

 able, becaufe the hard feel of the pulfe, and the abundance of 

 coagulable lymph commence, exift, and ceafe together. 



Great heat is produced from the new chemical combinations 

 arifing in the fecretion of new fibres, and great pain from the 

 diftention of old ones, or from their increafed adlion. The in- 

 creafed quantity of fenfation from a topical inflammation or 

 phlegmon is the immediate caufe of the febris fenfitiva irritata, 

 or inflammatory fever ; as when it arifes from the pain of pleu- 

 rify, or paronychia ; but generally an irritative fever precedes 

 this topical inflammation, which occurs during the hot fit of it ; 

 and then the irritative fever is changed into a fenfitive irritated 

 fever, by the additional caufe of the fenforia-1 power of fenfation 

 befides that of irritation. 



SPECIES. 



I. Febns fenfitiva irritata. Senfitive irritated fever, or in- 



flammatorr 



