January 13, 18727} 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
5G9 
minims of the strychnia fluid on a white non-porous sur¬ 
face, then and a few needles of chromic acid, which in¬ 
stantly dissolve, imparting to the liquid their charac¬ 
teristic tint. One or two drops of concentrated sulphuric 
acid are now added, and the play of colour is at once 
•evolved. With stronger solutions the result is very dis¬ 
tinct, and in any case unfailing. In applying this test 
the above method must be strictly adhered to; because 
if sulphuric acid he added to the strychnia solution before 
the chromic acid, the latter will not dissolve, and the 
result is negative. Chromic acid does not give the 
coloured reaction with dilute sulphuric acid. 
It is well known that bichromate of potassium, so com¬ 
monly used for this test, does not always succeed. I 
have seen it fail in the hands of two professors—one a 
celebrated toxicologist—when attempting to show it to 
their class, and am not aware that any explanation of 
the cause of this frequent miscarriage has been given, 
though it seems to me as follows:—It is obvious from 
the fact of chromic acid giving the coloured test at all 
that to it alone the reaction is due when bichrome is 
used; that neither the potash in the latter, nor the sul¬ 
phate of potash resulting from the addition of sulphuric 
acid, are indispensable agents in developing the reaction. 
Earthermore, as strong sulphuric acid is necessary both 
when using bichrome and chromic acid per se, it is evi¬ 
dent that, when added to the first, the result is the for¬ 
mation of sulphate of potassium, water, and free chromic 
acid: indeed, this is exactly the method by which the 
latter is prepared, as shown in the following equation:— 
K 2 0 2 Cr0 3 + H 2 S0 4 = IL,S0 4 + H 2 0 2 Cr0 3 . 
The chromic acid, being thus liberated, oxidizes the 
strychnia, and the coloured reaction is afterwards de¬ 
veloped by the strong sulphuric acid. But it may happen 
that the sulphuric acid, which might have proved strong- 
enough for isolated chromic acid, is rendered too weak 
for bichrome in consequence of being partially neutralized 
by the base of the latter, and further diluted by the 
water, which, as seen in the formula, is generated by 
the hydrogen of the sulphuric acid combining with the 
oxygen of the potash, and this, I believe, is the most 
frequent cause of non-success of the test. With isolated 
ohromic acid failure is of course impossible from such a 
source ; and when used as described, the reaction is not 
only constant, but greatly more delicate. Another cause 
of lapsus with the bichrome, also applying in part to 
chromic acid, is seen in the following table of results:— 
Bichrome added to solution of strychnia, then sulphuric 
acid added = much colour. 
Sulphuric acid added to solution of strychnia, then 
bichrome added = considerable colour. 
Sulphuric acid added to bichrome, then solution of 
strychnia added = almost no colour. 
Chromic acid added to solution of strychnia, then sul¬ 
phuric acid added = much colour. 
Sulphuric acid added to solution of strychnia, then 
chromic acid added = a little colour. 
Sulphuric acid added to chromic acid, then solution of 
strychnia added = almost no colour. 
These results are just what might have been expected. 
It will be seen, as with chromic acid, that when sulphuric 
acid is added to bichrome, or vice versd , succeeded by 
.strychnia, the reaction is almost nil. Doubtless, from 
the loose and empirical manner in which this test is 
usually applied, its failure is frequently due to the above 
•cause; and, indeed, from notes in my possession, I find 
this very method recommended. 
Antidote. —In poisoning with chromic acid the. best 
antidote is beef-tea, raw egg, milk, or any albuminous 
•or gelatinous substance. A very handy and efficient 
antidote is a solution of ordinary painters’ size. 
Therapeutical properties. —I am not aware what effect 
on the system prolonged minute doses of chromic acid 
(which may be absorbed) would produce, though, from 
its strong coagulating properties, a general viscidity of j 
the blood might be anticipated, whatever further conse¬ 
quences should arise. In the absence of such knowledge, 
it seems to me that it might be used with a fair prospect 
of success in the following cases, for some of which it is 
already recommended in works on materia medica;—As 
a haemostatic; as a caustic to cancerous tissues, chancres, 
condylomata, hospital gangrene, phagedcenic ulcers, bites 
of rabid animals, poisoned wounds, warts, haemorrhoids, 
etc.; as a wash to allay fetid discharges; as a gargle in 
diphtheria: as an injection in ozoena, uterine catarrh, 
leucorrhoea and gonorrhoea; to disinfect cholera and 
fever stools, for which it is admirably adapted; as a pre¬ 
ventive of suppuration, putrefaction, etc. In every case 
it must be used dissolved in water; and, except where a 
strong caustic effect is desired, • in medical or surgical 
cases, the solution should not be stronger than half a 
grain to the ounce, and be succeeded immediately after 
gargling or injection by the application of pure water. 
I have used chromic acid to a limited extent in the five 
latter affections above specified with a fair measure of 
success; in gonorrhoea and ozasna the results are espe¬ 
cially gratifying. Finally, I have no doubt that its re¬ 
markable antiseptic, disinfectant, and coagulating powers 
will suggest many applications in medicine, surgery and 
hygiene not above enumerated. 
Glasgow , December , 1871. 
THE CHINESE WHITE WAX INSECT. 
In his recently-published volume, ‘ Travels of a Pioneer 
of Commerce in Pig-Tail and Petticoats, on an Overland 
Journey from China towards India ’ (Murray, 1871), Mr. 
T. T. Cooper gives the following account of this insect, 
a species of coccus :—Chemists have long known the so- 
called “ vegetable wax,” “ Chinese wax” or “pcla,” also 
called “vegetable insect wax” or “ vegetable sperma¬ 
ceti,” but we have had no definite knowledge before of 
its history or mode of production. It was generally 
stated to be produced on certain trees by the puncture of 
a species of coccus. But Mr. Cooper supplies us with 
the first definite statement we have seen of what proves 
to be an extensive industry. Unfortunately, he does not 
appear to have secured specimens of the insects producing 
it, nor does he give us more definite information of the 
plant on which they feed than that it resembles our 
privet. Mr. Cooper describes the cultivation of wax as 
a source of great wealth to the province of S’zchuan, 
where it ranks in importance second only to that of silk. 
The eggs of the insect which produces the wax are 
imported annually from the districts of Hochin or 
Hoking- and Why-li-tzou in Yunnan, where the cul¬ 
ture of the eggs forms a special occupation, by mer¬ 
chants who deal in nothing else but pa-la-tan, “ white 
wax eggs.” The “wax-trees” are all uniformly cut 
down to a height of about eight feet, without a single 
branch, the stumps being as thick as a man’s thigh. The 
clusters of eggs, about the size of a pea, enclosed in balls 
of the young leaves, are suspended to the shoots by 
strings, about the middle of March. By the end of the 
month the larvae make their appearance, feed on the 
branches and leaves, and soon attain the size of a small 
caterpillar, or rather a wingless house-fly, covered with 
white down, with a delicate plume-like appendage, 
curving from the tail over the back. They are so nume¬ 
rous that the branches of the trees are whitened by them, 
and appear as if covered with feathery snow. The grub 
proceeds in J uly to take a chrysalis form, burying itself 
in a white wax secretion, just as a silk-worm wraps itself 
in its cocoon of silk. All the branches of the tree are 
thus completely coated with w r ax, an inch thick, and 
in the beginning of August are lopped off close to the 
trunk and cut into small lengths which are tied up in 
bundles and taken to the boiling-houses, where they are 
placed without further preparation in large caldrons of 
water, and boiled until every particle of the waxy sub . 
