iBi DISEASES Class II. i. 3. 



by certain animal motions of the terminations of the veffels. 

 Hence a new kind of gland is formed at the terminations of the 

 veiTels in the eruptions of the fmall-pox ; the animal motions of 

 which produce from the blood variolous matter ; as other glands 

 produce bile or faliva. Now if fome of this matter is introdu- 

 ced beneath the cuticle of a healthy perfon, or enters the circula- 

 tion, and excites the extremities of the blood-vefTels into thofe 

 kinds of difeafed motions, by which it was itfelf produced, either 

 by irritation or affociation, thefe difeafed motions of the extremi- 

 ties of the veffels will produce other fimilar contagious matter. 

 See Sect. XXXIII. 2. 5. and 9. Hence contagion feems to be 

 propagated two ways ; one, by the ftimulusof contagious mat- 

 ter applied to the part, which by an unknown law of nature ex- 

 cites the ftimulated veffeis to produce a fimilar matter •, as in 

 venereal ulcers, which thus continue to fpread ; or as when va- 

 riolous matter is inferted beneath the cuticle ; or when it is 

 fuppofed to be abforbed, and diffufed over the body mixed with 

 the blood, and applied in that manner to the cutaneous glands. 

 The other way^ by which contagion feems to be diffufed, is by 

 fome diftant parts fympathizing or imitating the motions of the 

 part firft affected ; as the ftomach and flcin in the eruptions of 

 the inoculated fmall-pox, or in the bite of a mad dog j as treat- 

 ed of in Seel:. XXII. 3. 3. 



In fome of the difeafes of this genus, the pulfe is throng, full, 

 and hard, conflituting the fenfitive irritated fever, as defcribed 

 in the preceding genus ^ as in one kind of eryfipelas, which re- 

 quires repeated venefection. In others the arterial action is 

 iometimes moderate, fo as to conftitute the fenfitive fever, as in 

 the inoculated frnall-pox ; where the action of the arteries is 

 neither increafed by the fenforial power of irritation, as in the 

 fenfitive irritated fever ; nor decreased by the defect of that pow- 

 er, as in the fenfitive inirritated fever. But in the greateft num- 

 ber of the difeafes of this genus the arterial action is greatly di- 

 minifhed in refpect to ftrength, and confequently the frequen- 

 cy of puliation is proportionally increafed, as explained in Sect. 

 XXXII. 2. 1. Which is owing to the deficiency of the fenfo- 

 rial pov/er of irritation joined with the increafe of that of fenfa- 

 tion, and thus conftitutes the fenfitive inirritated fever ; as in 

 fcarlatina with gangrenous tonfils. 



From this great debility of the action of the arteries, there 

 appears to be lefs of the coaguiable lymph or mucus fecreted on 

 their internal furfaces ; whence there is not only a defect of 

 that buff or fize upon the biood, which is feen on the furface of 

 that which is drawn in the fenfitive irritated fever 5 but the 

 blood, as it cools, when" it has been drawn into a baiin, fcarcely. 



coagulates ; 



