POTASSIUM HYDROXIDE 123 



•with calcium hydrate leaves potassium hydrate in solution, 

 •while calcium carbonate is precipitated. 



E, CO, + Ca (OH), = 2 KOH + Ca CO^. 



Properties.— K clear, colorless liquid, odorless, having a 

 very acrid and caustic taste and a strongly alkaline reaction. 

 It has a soapy feel and taste. 



Dose.—R. & C, § ss.-i. (15.-30.) ; Sh. & Sw., 3 ss.-i. 

 (2.-4.); D., H^v.-xx. (.3-1.3). 



PoTASSA Cum Caloe. Potassa •with Lime. (Non-official.) 

 (Equal parts of potassa and lime.) 

 Synonym. — Vienna paste. 



Properties. — A grayish-white powder, deliquescent, 

 , having a strongly alkaline reaction ; should be soluble in 

 diluted hydrochloric acid without leaving more than a small 

 residue. 



Action and Uses. — Potassium hydroxide, its solution, and 

 potassa cum calce are mainly of value as escharotics. Liquor 

 potasssB is unfit for internal use unless greatly diluted with 

 water. It resembles potassium carbonate in its effects. 

 Caustic potash is very destructive of tissue by dissolving 

 proteids and forming alkali-proteids. It is most diffusible 

 and, therefore, difficult to limit its action. This we may do, 

 however, by applying a piaster to a part, with a hole in it, 

 through which the caustic stick is applied. Before using 

 the caustic, the outside of the plaster should be covered with 

 oil or grease, but not the part under the aperture in it. 

 After removing the plaster the operation of the caustic may 

 be arrested by vinegar. Cauterization by this means is very 

 painful under ordinary circumstances, but may be made 

 comparatively painless by incorporating one part of mor- 

 phine muriate with three parts of potassa cum calce, and 

 adding enough chloroform to make a paste. 



Caustic potash is indicated where extensive destruction 

 of tissue is desirable, as in the treatment of the bites of rabid 

 dogs and of snakes. It is less commonly used for the 



Digitized by Microsoft® 



