‘September 2,1871.] THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
isa 
in a bottle. If it is put in a proper box, it might be 
kept in perfection for an unlimited period. 
I\Ir. Schacht said that Mr. Horncastle had spoken of 
the difficulty of keeping- the sulphate of iron free from 
change, and that it was less likely to change if kept in a 
Fox than in a bottle. That was a new idea, and he could 
scarcely have expected the result; but, of course, there 
was the well-known fact, practically more interesting, 
■.that a little piece of camphor put into the bottle pre¬ 
vented the change. He noticed that it had that effect; 
and if it was the case that a little bit of camphor pre¬ 
vented any change, it must be some chemical influence, 
and he should like to know if any gentleman could give 
an explanation of that which was a great mystery. 
Mr. Matthews said that as to keeping sulphate of 
iron in a box, he had not done so, but he had kept che¬ 
mically pure sulphate of iron in a loosely-corked bottle, 
.and it did not suffer any change in the course of five or 
six years. The cork had not been changed. Pie had 
not tasted it, but the colour was as good as when he re¬ 
ceived it. 
Mr. Williams said he found that the crystals would 
keep for a considerable period when they were solid. 
There were certain kinds of sulphate of iron that would 
.keep, and it was because of the density and solidity of 
.the crystals, and did not depend upon the impurity of 
the metal. 
Professor Attfield said that many specimens of sul¬ 
phate of iron made by the students came under his 
notice every year, and he found that when absolution gave 
.single crystals those single crystals were always hard, 
.and some that had no interstices between the plates 
would keep remarkably well. It was a fact, that the 
single crystals, the hard crystals, kept perfectly well; 
hut with the masses of sulphate of iron they did not 
.keep. 
Mr. Horn castle said that this subject had occupied 
,his attention for some years, and he believed the presence 
■of water, which was enclosed within the masses of 
■ crystals, was the source of difficulty. 
Mr. Robbins was of opinion that the keeping qualities 
of the crystals depended on their hardness and freedom 
from water, mechanically retained in thin interstices; 
nnd mentioned as an example that he had a natural 
• crystal of large size, which was kept in a glass case for 
some years, showing scarcely a trace of oxidation. 
.Report ox the Permanganate of Potassium of 
Pharmacy. 
BY ALFRED H. ALLEN, F.C.S., 
Lecturer on Chemistry at the Sheffield School of 
Medicine, etc . 
Permanganate of potassium occurs in the form oi 
prismatic crystals, so deep in colour as to appear black, 
with brilliant coloured reflections. The crystals are 
■ anhydrous, permanent in the air, and soluble in about 
sixteen parts of cold water. The solution is neutral to 
test paper and a most powerful oxidizing agent, organic 
matter being- rapidly turned brown by the reduced salt. 
The amount of real permanganate was estimated by- 
dissolving the salt in 500 parts of distilled water, and 
•deoxidizing it by an accurately measured quantity 7 of oxalic 
.acid solution of known strength, the liquid being acidified 
with sulphuric acid. This is the ordinary method of 
■ determining the strength of solutions of permanganate, 
and is rapid and accurate. 
The oxalic acid solution at first employed contained 
63 grammes of the cry-staliized acid in 1000 grammes 
of distilled water. In the latter experiments a solution 
of half this strength was used. 
Five atoms of oxalic acid are deoxidized by- two atoms 
of permanganate, therefore 630 parts H.,C 2 0 4 + 2aq. 
.“316 parts KMnCb = 80 parts available oxygen. 
No. 1 was a sample of Crystallized permanganate of 
jpotassium obtained in Sheffield. It was dissolved in 
500 parts of water, and decolorized with the standard 
oxalic acid, of which 10 c. c. were oxidized by 163 c. c. 
of the permanganate. These numbers correspond to a 
percentage of 96-93 of pure permanganate. 
No. 2 sample was bought in Newcastle-upon-Tyne. 
The crystals were larger than those composing No. 1, 
and it was chosen as the best of several specimens. Tho 
mean result of the analyses showed a percentage of 
potassium permanganate of 98-87. 
No. 3 had been in the possession of the author nine or 
ten y 7 ears, and was purchased in London. It contained 
93*55 per oent. of real permanganate. 
Following are the tabulated results of the examination 
of the above three samples: — 
No. 1. No. 2. No. 3. 
Per cent. Per cent. Per cent. 
Real KMn0 4 .... 96-93 98-87 93-55 
Available Oxygen. . . 24 - 54 25-03 23-69 
All three samples contained traces of sulphate, but no 
chloride. On solution in water they left a small quantity 
of a heavy r , dark-coloured residue. That from No. 3, 
which was largest in quantity, dissolved in oxalic acid 
with effervescence, and the solution, rendered alkaline 
with ammonia, gave a brownish precipitate with potas¬ 
sium ferricyanide, proving the residue to have been 
manganese dioxide. The residues from Nos. 1 and 2 
seemed similar. 
The liquor potassse permanganatis of the British Phar¬ 
macopoeia contains 80 grains of the salt to the pint of 
water = 
KMn0 4 = 0-9143 per cent. 
= 9-143 grammes per litre. 
= Available Oxygen 2-315 ,, ,, 
A sample of Condy’s Crimson Disinfecting Fluid had 
an oxidizing power equal to— 
KMn0 4 1-550 per cent. 
= 15-50 grammes per litre. 
= Available Oxy r gen 3-921 ,, ,, 
A specimen of Condy 7 ’s Green Fluid had almost as 
great an oxidizing power as the crimson. The active 
oxy-gen of an equal number of atoms of manganate and 
permanganate is as 4 : 5, and the atomic weight of the 
former salt being higher, gives the calculated amount of 
manganate of potassium in the green fluid as— 
K 2 MnO 4 = 24-0 grammes per litre. 
= Available Oxyrgen 3-883 ,, ,, 
The oxidizing power of the green fluid is not entirely 
due to manganate, as a small but variable amount of 
permanganate is always present. This may be detected 
by- precipitating- the manganate with barium chloride 
and filtering through asbestos, when the crimson colour 
of the permanganate becomes apparent. 
A qualitative analysis proved the crimson fluid to 
contain much sulphate,‘evidently due to^ the sulphuric 
acid empioy-ed to neutralize the excess of alkali in the 
crude product. The green fluid was strongly alkaline, 
the crimson nearly 7 neutral. In other respects they were 
similar. 
It was not thought requisite to examine_ a larger 
number of specimens of permanganate, as inquiry- proved 
it to be of limited application in pharmacy, and the 
above results showed that the crystallized salt was prac¬ 
tically pure. _ 
Dr. Attfield read a paper on— 
Use of Blistering Flies in Hydrophobia. 
BY HENRY GROVES, OF FLORENCE. 
The paper on Chinese blistering-flics by Dr. F. Porter 
Smith, recently 7 published in the Medical limes and Ga¬ 
zette, mentions" the employ-ment by Chinese practitioners 
of blistering insects in cases of hydrophobia; and as I 
I am not aware of the remedy- being similarly used in 
