ART. IV. 2. i. 3 - SORBENTIA. 45 



as in hectic fever, which has been of fome continuance, or in 

 fpurious peripneumony, a grain of opium given at night will 

 fometimes prevent the appearance of fweats ; which is owing to 

 the ftimulus of opium increafing the actions of the cutaneous 

 abforbents, more than thofe of the fecerning veflels of the (kin. 

 Whence the iecretion of perfpirable matter is not decreafecl, 

 but its appearance on the {kin is prevented by its more facile 

 abforption. 



3. There is one kind of itch, which feldom appears between 

 the fingers, is the leaft infectious, and molt difficult to eradicate, 

 and which has its cure much facilitated by the internal ufe of 

 acid of vitriol. This difeafe confifts of fmall ulcers in the ikin, 

 which are healed by whatever increafes the cutaneous abforp- 

 tion. The external application of fulphur, mercury, and acrid 

 vegetables, acts on the fame principle ; for the animalcula, 

 which are feen in thefe puftules, are the effect, not the caufe, of 

 them ; as all other ftagnating animal fluids, as the femen itfelf, 

 abounds with fimilar microfcopic animals. See Dyfentery, 

 ClafsII. i. 3. 18. 



4. Young children have fometimes an eruption upon the head 

 called tinea, which difcharges an acrimonius ichor inflaming 

 the parts, on which it falls. This eruption I have feen fubmit 

 to the internal ufe of vitriolic acid, when only wheat-flour was 

 applied externally. This kind of eruption is likewife frequent- 

 ly cured by teftaceous powders ; two materials fo widely differ- 

 ent in their chemical properties, but agreeing in their power of 

 promoting cutaneous abforption. 



II. Abforption from the mucous membrane is increafed by 

 applying to its furface the auftere acids, as of vitriol, lemon-juice, 

 crab-juice, floes. When thefe are taken into the mouth, they 

 immediately thicken, and at the fame time leflen the quantity of 

 the faliva ; which laft circumftance cannot be owing to their 

 coagulating the faliva, but to their increafing the abforption of 

 the thinner parts of it. So alum applied to the tip of the tongue 

 does not flop in its action there, but independent of its diffufion 

 it induces cohefion and corrugation over the whole mouth. (Cul- 

 len's Mat. Med. Art. Aftringentia.) Which is owing to the 

 affociation of the motions of the parts or branches of the abforb- 

 ent fyftem with each other. 



Abforption from the mucous membrane is increafed by opium 

 taken internally in fmall dofes more than by any other medicine, 

 as is feen in its thickening the expectoration in coughs, and the 

 difcharge from the noftrils in catarrh, and perhaps the difcharge 

 from the urethra in gonorrhoea. The bark feems next in pow- 

 er for all thefe purpofes. 



External!? 



