544 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
[January 6,1872. 
rature. Five months afterwards, the 20th of October, 
the tubes were opened. The solutions were perfectly 
transparent, and contained no microscopic vegetation. 
That which had been kept in darkness gave no re¬ 
action with the cupro-potassic test of M. Barreswil, 
thus showing that it contained no glucose. When 
that reagent, however, was added to the solution 
which had been exposed to the light, it caused an 
abundant red precipitate. About half the cane- 
sugar at first contained in the solution was found 
to have changed; so that under the influence of 
light, cane-sugar dissolved in water changes slowly 
into glucose. 
It results from this that a syrup might contain a 
considerable quantity of glucose, although cane-sugar 
only had been used in its manufacture, and that such 
an occurrence is not necessarily evidence of an adul¬ 
teration. 
At a subsequent sitting of the Academy, * a note 
was read relative to this subject, from M. Maumene, 
in which that gentleman stated that he • had many 
years since indicated the possibility of the slow trans¬ 
formation of cane-sugar into glucose without the 
intervention of a ferment. 
Caters for Stotnts. 
CHEMICAL NOTES TO THE PHARMACOPOEIA. 
BY WILLIAM A. TILDEN, D.SC. LOND. 
DEMONSTRATOR OP PRACTICAL CHEMISTRY TO THE 
PHARMACEUTICAL SOCIETY. 
Potass.e Nitras, KNOj.—E xists ready-formed 
in the juices of many plants, and sometimes appears 
as an efflorescence upon the surface of extracts. It 
is also a common constituent of well and river waters. 
It is, however, always obtained from the earth, being 
found in various districts in the East Indies as a 
saline crust or deposit upon or near the surface of 
the soil. It is simply dissolved out, and, to purify it, 
is recrystallized several times. It is also made arti¬ 
ficially by exposing a damp mixture of nitrogenous 
organic refuse and lime or wood ashes to the air. 
[§ In white crystalline masses or fragments of 
striated six-sided prisms.] It is anhydrous, and 
therefore unlike sulphate of sodium ; for example, it 
does not effloresce. [§ Thrown on the fire it defla¬ 
grates ; warmed in a test-tube with sulphuric acid 
and copper-wire, it evolves ruddy fumes.] It should 
be free from chloride and sulphate. 
Fused and moulded, it forms sal-prunella. Heated 
more strongly it loses a portion of its oxygen, leaving, 
if it be stopped at the right point, potassic nitrite, 
KN 0 2 , or ultimately a mixture of the oxides of po¬ 
tassium K 2 0 and k 2 0 2 . In the fused state it is 
often employed as an agent of oxidation, as, for ex¬ 
ample, in making arseniate of sodium. 
Potass.e Permanganas, K 2 Mn 2 O g .—Is always 
produced by the decomposition of the manganate, 
K 2 Mn0 4 . 
The manganate of sodium is made on the large 
scale by exposing to a dull red heat for many hours 
a mixture of caustic soda and peroxide of manga¬ 
nese : oxygen is absorbed from the air. 
2NaHO + Mn0 2 + 0 = Na 2 Mn0 4 + H 2 0. 
According to the Pharmacopoeia, which adopts the 
* Comptes Rendus, vol. lxxiii. p. 1176. 
usual method, a mixture of caustic potash and man¬ 
ganese oxide acquires the necessary oxygen by fusion 
with chlorate of potassium. 
3(2KHO + Mn0 2 ) -f KC10 3 = 
3(K 2 Mn0 4 4- H 2 0) + KC1. 
The heat must be carefully applied, or the product 
will be decomposed. A scarcely visible heat for 
about twenty minutes is sufficient for a small quan¬ 
tity. The green mass, boiled in water, yields a 
green solution, which is strongly alkaline. This is 
mixed with dilute sulphuric acid till the colour 
changes to bright purple, is evaporated quickly, de¬ 
canted from the deposited peroxide of manganese, 
and set to crystallize. Chlorine or carbonic acid gas 
passed into the solution is better than sulphuric acid 
for the transformation of manganate into permanga¬ 
nate. I 11 either case the change is simply due to 
the abstraction of half the potassium, but when the 
acid is employed, one-tliird of the manganese is pre¬ 
cipitated as peroxide. 
3K 2 Mn0 4 + 2 H 2 S 0 4 
Manganate. 
Or 2K 2 Mn0 4 + K 2 0 . Mn0 2 . O + 2H 2 S0 4 
=K 2 Mn 2 O g + Mn0 2 -f 2 K 2 S 0 4 -f 2H 2 0. 
Permanganate. Peroxide of Sulphate of Water. 
Manganese. Potassium. 
When chlorine is employed— 
2 K 2 Mn 0 4 + Cl 2 = K 2 Mn 2 0 3 -f 2KC1. 
Manganate. Permanganate. 
The solutions cannot be filtered. 
The salt is easily recognized when in the solid 
form by the purplish semi-metallic lustre of the crys¬ 
tals, and by the intensely purple solution which they 
yield. 
It must not be forgotten that the salt is decom¬ 
posed, and its colour destroyed, with formation of a 
brown deposit of peroxide of manganese, by organic 
matters of every kind. Tinctures, infusions and 
vegetable preparations are therefore incompatible 
with it, as are also such tilings as glycerine, sulphate 
of iron, sulphurous acid, essential oils, and many 
others. 
CHROMIC ACID AS AN ANTISEPTIC, 
DISINFECTANT, ETC., 
More Especially as Compared with Carbolic Acid.* 
BY JOHN DOUGALL, M.D. GLAS. 
Chromic acid occurs in brilliant crimson needles, which 
deliquesce by exposure to the air. When pure it is al¬ 
most odourless. Its aqueous solution has a sour metallic 
taste, and a rich amber or reddish-brown colour. It is 
very soluble in water, sparingly soluble in chloroform, 
insoluble in the fixed oils and fats. Contact with car¬ 
bolic acid, mucilage, glycerine, alcohol, ether, and with 
organic matter generally, instantly decomposes it with 
more or less violence, oxygen being evolved and heat 
generated. 
Antiseptic properties. —As an antiseptic, disinfectant, 
and preventive of germ growth, chromic acid stands 
“ second to none.” Several varied experiments were 
made in order to ascertain its antiseptic powers in con¬ 
trast with those of carbolic acid. One detailed may 
suffice, all the others confirming it. One ounce of ox 
muscle was immersed for twenty-four hours in four 
ounces of an aqueous solution of chromic acid (1-2000), 
then suspended in air. In two days it was quite black, 
and in six days as hard as wood, in which condition it 
* Reprinted from tlie Lancet, vol. ii. (1871) p. 847. 
