38 

 paialytic aifection of the optic nerve. The treat- 

 iiieut of both may be seen imder the article Eyes^ 



BLISTERING 



fs an operation of great utihly, and is, perhaps, 

 the safest that is performed. BHsters act by inflam- 

 ing the skin, which, drawing a large qnantity of blood 

 jto the partj its watery portion, or serum, is sepa- 

 rated, and this forms the rumiing. In a day or two 

 the irritation of the blister ceases, and the part is 

 then in the condition of a common wound, and, as 

 such, produces pus, or matter. At the same time, 

 likewise, that a blister acts on the skin, it stimulates 

 the surrounding absorbents to take up other fluids ; 

 jind if the blister is strong, and they are much excited, 

 these same absorbing vessels remove even the solids 

 likewise. 



Mercury is known to stimulate these vessels more 

 tlian most other substances ; therefore, ^^ hen we wish 

 particularly to stir up the absorbents to remove a 

 part, we make use of a mercurial blister; that is, 

 calomel, or corrosive sublimate, is mixed with the 

 Spanish flies, euphorbium, or whatever the blister is 

 composed of. Mercurial blisters are therefore used 

 for splents, curbs, ring-bones, &c.; but when we 

 wish only to inflame a part, thereby to draw the in- 

 flammation from some other part, we content our- 

 selves with the flies, or otlier simply irritating subf 

 stance. 



It is a law in the animal economy, that two ia- 

 flammations seldom exist in the vicinity of each 

 jother; therefore, when an inflammation has taken 

 place in any part, and we wish to remove it, we at^ 



