124 Materia Medica. 



of turpentine, i oz. ; hog's lard, 4 oz. ; powdered can- 

 tharides, i oz. Mix, and spread. 



6. Very Siro?ig Blister (counter-irritant). — Strong mer- 

 curial ointment, 4 oz. ; oil of origanum, \ oz. ; finely- 

 powdered euphorbium, 3 drms. j powdered cantharides, 

 \ oz. Mix, and spread. 



7. Rapidly Acting Blister (counter-irritant). — Best 

 flour of mustard, 8 oz., made into a paste with water. 

 Add spirit of turpentine, 2 oz. \ strong liquid of ammonia, 

 I oz. This is to be well rubbed into the chest, belly, or 

 back, in cases of acute inflammation. 



8. Sweating Blister. — Strong mercurial ointment, 2 0z. ; 

 oil of origanum, 2 drms. : corrosive sublimate, 2 drms. ; 

 cantharides powdered, 3 drms. Mix, and rub in with 

 the hand. 



9. Tincture of Iodine^ which should be painted on 

 with a brush daily, until it causes the cuticle to exfoliate. 

 It may then be omitted for a few days, to be resumed 

 after that interval. 



Caustics. — Substances capable of exerting chemical 

 action on the living tissues are known as caustics, such 

 action being simply burning or decomposition. The 

 most familiar example is the actual or potential cautery, 

 or heated iron. Chemical agents as caustic soda, caustic 

 potash, and lunar caustic, or nitrate of silver, are also 

 variously employed. The general use is to stimulate 

 indolent wounds, repress luxuriant granulations, also 

 removing tumours, or parts destroyed by sloughing, and 

 arresting the flow of blood from injured vessels. 



1. Caustic Potash is conveniently sold in sticks or 

 pencils, and requires a suitable holder for operating with 

 it. Its action is prompt and powerful, but being liable 

 to become fluid when exposed to the atmosphere, its 

 use is sometimes limited. 



2. Lu?iar Custic, or nitrate of silver, is by far the most 

 manageable, and effective. It is sold in pencil form, 

 and also requires a holder of silver or platinum for its 

 preservation. 



3. Sulphate of copper, burnt alum, verdigris, red pre- 

 cipitate, and corrosive sublimate are used in powder as 



