DISEASES GtAssI. 2. i. i s . 



born with the eruption on them. The blood in the fmall pox will 

 not inoculate that difeafe, if taken before the commencement of 

 the fecondary fever ; as fhewn in Sect. XXXIII. 2. 10. becaufe 

 the contagious matter is not yet formed, but after it has been 

 oxygenated through the cuticle in the puftules, it becomes con- 

 tagious ; and if it be then abforbed, as in the fecondary fever, 

 the blood of the mother may become contagious, and in feel: the 

 child. The fame mode of reafoning is applicable to the chicken 

 pox, See CJafsIV. 3. i. 7. 



15. Scorbutus. S.ea-fcurvy is ca.ufed by fait diet, the perpet- 

 ual itimulus of which debilitates the venous and abforbent fyf- 

 tems ; and may alfo be promoted by the fea-air, which is known 

 to be fo injurious to moft vegetables, which grow near the coafts, 

 and has been perhaps incaurioufly recommended to confumptive 

 patients. See Clafs II-. i. 6. 7. Hence the blood is imperfect- 

 ly taken up by the veins from the capillaries, whence browi* 

 and black fpots appear upon the Jkin without fever. The limbs 

 become livid and edematous, and laftly ulcers are produced from 

 deficient abforption. See Sect. XXXIII. 3. 2. and Clafs II. i. 

 4. 13. For an account of the fcurvy of the lungs, fee Seel. 

 XXVII. 2. 



M. M. Frefli animal and vegetable food. Infufion of malt. 

 New beer. Sugar. Wine. Steel. Bark. Sorbentia, Opium ? 



1 6. Vibices. Extravafations of blood become black from their 

 being fecluded from the air. The extravafation of blood in 

 bruifes, or in fome fevers, or after death in fome patients, ef- 

 pecially in the parts which were expofed to prerTure, is owing 

 to the fine terminations of the veins having been mechanically 

 comprefled fo as to prevent their abforbing the blood from the 

 capillaries, or to their inactivity from difeafe. The blood when 

 extravafated undergoes a chemical change before it is fufficient- 

 ly fluid to be taken up by the lymphatic abforbents, and in that 

 procefs changes its colour io green and then yellow. 



17. Petechia. Purple fpots. Thefe attend fevers with great 

 venous inirritability, and are probably formed by the inability 

 of a fingle termination of a vein, whence the correfponding 

 capillary becomes ruptured, and effufes the blood into the cellu- 

 lar membrane round the inert termination of the vein. This is 

 generally efteemed a fjgn of the putrid (late of the blood, or that 

 ilate contrary to the inflammatory one. As it attends fome in- 

 flammatory difeafes which are attended with great inirritability, 

 as in the confluent fmall pox. But it alfo attends the fcurvy, 

 where no fever exifts, and it therefore {imply announces the. in- 

 activity of the terminations of fome veins 5 and is thence int. 



a bad fymptom in fevers, as a mark of approaching inactivity of 



