THE 
VETERINARIAN. 
VOL. XXXI, 
No. 363. 
MARCH, 1858. 
Fourtli Series, 
No. 39. 
ON THE PERMANGANATE OP POTASSA. 
The attention of the medical profession has lately been 
drawn to the use of the above agent, in the pages the Lancet , 
by Dr. G. F. Girdwood. 
We have not heard of its being employed by veterinary 
surgeons, nevertheless it seems to possess properties that 
recommend it to their notice. 
Referring to this compound, Brande says : “ When per- 
oxide of manganese is heated to redness with nitrate of potassa, 
a compound is obtained, which, when put into water, fur- 
nishes a solution exhibiting tints of green, purple, and red ; 
and which was therefore called chameleon mineral, A similar 
compound is more perfectly obtained by fusing the peroxide 
with caustic potassa at a red heat, which becomes a green 
substance when the alkali is in excess. With water it affords 
a deep green solution of manganate of potassa, which is per- 
manent with excess of alkali, but otherwise becomes blue, 
purple, and ultimately red, on exposure to air, in conse- 
quence of the formation of permanganate of potassa by the 
absorption of oxygen ; at the same time it deposits a brown 
powder, which is hydrated peroxide of manganese, and free 
alkali is separated.” 
Fownes states, that “ hypermanganate of potash is easily 
prepared on a large scale as follows : Equal parts of very 
finely powdered peroxide of manganese and chlorate of 
potash are mixed with rather more than one part of hydrate 
of potash dissolved in a little water, and the whole exposed, 
after evaporation to dryness, to a temperature just short of 
ignition. The mass is treated with hot water, the insoluble 
oxide separated by decantation, and the deep purple liquid 
concentrated by heat until crystals form upon its surface ; it 
is then left to cool. The crystals have a dark purple colour, 
and are not very soluble in cold water.” 
XXXI. 
17 
