CLASS II. 1. 2. 1. OF SENSATION. 163 



may be esteemed its essential character, or the criterion of its 

 existence. The extension of the old vessels seems rather a con- 

 sequence than a cause of the germination, or pullulation, of these 

 new ones; for the old vessels may be enlarged, and excited with 

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

 blush of shame or of anger. 



When these new vessels are formed, if they are not reabsorbed 

 into the circulation, they secrete a new fluid called purulent mat- 

 ter; which generally opens itself a passage on the external skin, 

 and produces an ulcer, which either gradually heals, or spreads, 

 and is the cause of hectic fever; or they secrete contagious mat- 

 ter, which has the property of exciting the same kind of inflam- 

 mation, and of producing the same kind of contagious matter, 

 when inserted by inoculation into the skin of other persons. 

 These contagious matters form ulcers, which either heal sponta- 

 neously, or by art; or continue to spread, and destroy the pa- 

 tient, by other kinds of hectic fever. 



In this genus there is an increase of the sensorial power of ir- 

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

 produced, and the pulse becomes strong and full, as well as quick; 

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

 themselves thickened and distended by inflammation. The blood 

 drawn, especially at the second bleeding, is covered with a tough 

 size; which is probably the mucus from the inflamed internal 

 surface of the arteries, increased in quantity, and more coagulable 

 than in its natural state; the thinner part being more perfectly 

 absorbed by the increased action of the inflamed absorbents. See 

 Sect. XXXIII. 2. 2. This is rendered more probable, because 

 the hard feel of the pulse, and the abundance of coagulable 

 lymph commence, exist, and cease together. 



Great heat is produced from the new chemical combinations 

 arising in the secretion of new fibres, and great pain frbm the 

 distention of old ones, or from their increased action. The in- 

 creased quantity of sensation from a topical inflammation or 

 phlegmon is the immediate cause of the febris sensitiva irritata, 

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

 risy, 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 sensitive irritated 

 fever, by the additional cause of the sensorial power of sensation 

 besides that of irritation. 



SPECIES. 



1. Febris sensitiva irritata. Sensitive irritated fever, or in- 



