BLISTERS.— CAUSTICS. 407 



beneath. In all cases the hair ought to be cut off as closely as 

 possible. 



A mild blister : 



25. — Powdered cantharjdes, 5 or 6 drachms. 

 Venice turpentine, 1 ounce. 

 Lard, 4 ounces. — Mix, and rub in. 



Strong blister : 



26. — Strong mercurial ointment, 4 ounces. 

 Oil of origanum, £ ounce. 

 Finely powdered euphorbium, 3 drachms. 

 Powdered cantharides, £ ounce. — Mix. 



Very quick blister : 



27. — Flour of mustard, 4 ounces. 

 Spirit of turpentine, 1 ounce. 

 Strong liquid of ammonia, £ ounce. 

 Mix the mustard with water into a paste, then add the other ingredients 

 and rub in. 



For bony growths or other tumours: 



28. — Tincture of Iodine. 

 Painted on every day, by means of a coriimon painter's brush. 



or, 



29. — Bed iodide of mercury, 1 to i£ drachms. 

 Lard, 1 ounce. 

 Mix, and rub in a piece the size of a nutmeg every day, keeping the 

 part wet with tincture of arnica £ ounce, mixed with half a pint of 

 water. 



CAUSTICS. 



This name is given to substances which either actually or 

 potentially destroy the living tissue ; the actual cautery is an 

 iron heated in the fire, the potential of some chemical substance, 

 such as corrosive sublimate, lunar caustic, caustic potash, a mineral 



