204 INORGANIC AGENTS 



potash, E.; permanganate de potasse, Fr.; uebermangan- 

 saures kali, G. 



Derivation. — Caustic potash, chlorate of potassium and 

 black oxide of manganese are fused together. 6 KHO + 

 KCIO3 + 3 MnO, = 3 K,MnO, 4 KCl + 3 H,0. The 

 manganate of potassium is boiled with water till the color 

 changes to purple and the permanganate is formed. 8 K, 

 MnO, + 2 H,0 = 2 KMnO, + 4 KHO + MnO,. The liquid 

 is neutralized with carbonic dioxide gas and evaporated. 



Properties. — Slender, monoclinic prisms, of a dark purple 

 color, odorless, and having a taste at first sweet, but after- 

 wards disagreeable and astringent ; permanent in dry air ; 

 soluble in 16 parts of water ; undergoes decomposition with 

 alcohol ; reaction neutral. 



Incompatibles. — It is very readily deoxidized in the pres- 

 ence of organic matter. 



Dose. — H., gr.xv.-xx. (1.-1.3) in one pint of water; D., 

 gr.i.-ii. (.06-.12), in pill, or tablet, with kaolin. 



ACTION OF POTASSIUM PERMANGANATE. 



External. — Potassium permanganate, like hydrogen 

 dioxide, is a powerful oxidizing agent. It quickly parts 

 with it^s oxygen in contact with organic matter, largely in the 

 form of ozone, and is broken up into black oxide of manga- 

 nese and potassa. Solutions, which are of a purple hue, 

 change into a dark brown color when this transformation 

 occurs, and are no longer of any medicinal value. This 

 action is exceedingly rapid and transient, and its effects 

 correspondingly so on the tissues. For this reason, and 

 because bacteria are so cordbined with organic matter in the 

 tissues, its action is largely exerted on the latter, and potas- 

 sium permanganate is, therefore, a better antiseptic than 

 disinfectant. The antiseptic action of potassium perman- 

 ganate is, moreover, quite superficial, since it parts with its 

 oxygen so soon as it comes in contact with the albumin of 

 the tissues. Outside of the body, permanganate of potash 

 is a disinfectant, but it is too expensive for general 

 purposes. In powder it is slightly caustic, owing to the 

 potassa set free in its decomposition ; and in solution is 



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