4GG 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. [December 9,1871 
line. The presence of the latter in the sample 
solution is, therefore, of no consequence. 
G. Though solution of narceine does not reduce 
iodic acid, yet after being heated with lime or potash, 
it has that effect. But the proportion of narceine 
existing in opium appears to be so minute, there 
can be no risk of error from this source. 
The requisite conditions being now better under¬ 
stood, the samples were examined afresh by the 
reduction process, and this time the results were 
deemed satisfactory. 
This sketch of the course of the inquiry may serve 
acid, B. P., and water up to the mark and mix well. 
Finally, shake the small quantity of solution re¬ 
quired for experiment—about half an ounce—with a 
fourth of its bulk of carbon disulphide, and pass it 
through a filter. 
'The Experiment. —Measure off with the pipette 
100 grain-measures of the sample solution, and 
transfer it to one of the trial-tubes, add 100 grain- 
measures of carbon disulphide, and lastly, 50 grain- 
measures of iodic acid solution; then immediately 
close the tube with a sound cork and shake briskly 
for half a minute. The rose-coloured solution of 
to explain some parts of the process finally adopted, iodine quickly subsides, but its brightness is some¬ 
times rather obscured by a slight filmy deposit on 
the glass. In this case pour the contents of the 
like ordinary test-tubes in form, about eight inches tube into a clean one. Take next 100 grain-measures 
in length and of exactly equal bore, which should i of the standard solution of morphia, and using a, 
be about half an inch. At first I used graduated j fresh tube, repeat the operation just described, 
tubes, but afterwards found it better to employ sepa- j Compare now the two rose-tinted liquids by holding 
which I will proceed to describe : 
Apparatus. —Three strong tubes of colourless glass, 
rate measures of smaller calibre, viz. a pipette to 
deliver 100 grain-measures ; a tube-measure for 50 
and 100 grain-measures ; and a smaller one for 5, 
7'5 and 10 grain-measures. 
Standard Solution of Morphia. —Weigh off accu¬ 
rately one grain of pure and well-dried morphia, 
and dissolve it in 50 grain-measures of diluted sul¬ 
phuric acid, B. P., and sufficient distilled water to 
make the volume exactly 1000 grain-measures. This 
solution will keep without appreciable change for 
some weeks. 
Solution of Iodic Acid. —Place in a flask 100 
grains of iodine, 100 grains of potassium chlorate, 
1 fluid drachm of strong nitric acid and 2 ounces of 
water. Heat the mixture until the iodine is per¬ 
fectly oxidized; nearly neutralize with sodium car¬ 
bonate, then add an excess of solution of barium 
chloride. Wash the barium iodate by decantation, 
and boil it for half an hour with a fluid drachm of 
strong sulphuric acid and 3 ounces of water. When 
cold, filter and add water to make the bulk G fluid 
ounces. 
the tubes side by side between the eye and a white 
cloud, or placing them against thin white paper at¬ 
tached to a window-pane. If the colours are equal 
in intensity, the powdered sample contains 10 per 
cent, of morphia. If unequal, add to the deeper one 
carbon disulphide in small successive measured 
quantities—say of 5 or 10 gram-measures at a time, 
as may seem necessary,—gently mixing it in with 
a glass rod. When by this means the tints have 
been rendered equal in depth, the calculation is 
simple. 
Let v — volume in grain-measures of standard 
colour; 
Let v' =■ volume in grain-measures of sample 
colour; 
‘ X 10 
then 
v 
x = percentage of morphia in pow¬ 
dered sample. 
And if w = percentage loss of weight in drying, 
100 — tv X x , „ -i . . . 
- = percentage oi morphia m moist 
100 
Sample Solution. —If the opium is in the moist! sample. 
state, dry 100 grains on the water-batli, and after 
P recaution.- 
noting the loss in weight reduce it to fine powder, remain colourless 
Put 20 grains of the powder into a two-ounce flask ioclic acid 
with 1 grain of oxalic acid and half a fluid ounce 
The carbon disulphide used must 
when shaken with solution of 
1 grain of oxalic acid and half a fluid ounce 1 In order to test the ability of the eye to discern 
of alcohol sp. gr. 0‘838, and having attached a con- slight inequalities of tint, the relative quantities of 
densing-tube to the flask, place the lower part of iodine in the standard and sample colours were 
the latter in water hot enough to cause the spirit to 
boil gently, and continue the boiling for half an 
hour. Filter into a porcelain dish, and wash the 
residue with half a fluid ounce of hot spirit. Add 
to the filtrate half an ounce of water, and evaporate 
down to about a quarter of an ounce, stirring fre¬ 
quently, then add an ounce of cold water. After 
the mixture has stood for ten minutes or so, remove 
the precipitated resinoid matter by the filter, and 
wash it with a little cold water, adding the washings 
to the filtrate. Boil the latter with 10 grains of 
slaked lime for two or three minutes, filter, and 
wash the calcium compounds with hot water. 
Slightly acidulate the filtrate with solution of oxalic 
acid, and evaporate it down to about a fluid ounce. 
After cooling, add 12 grains of caustic potash and 
set aside for a quarter of an hour; then filter, and 
wash the precipitate with a drachm of liquor po¬ 
tass®, diluted with two or three times as much 
water. Divide the filtrate into two exactly equal 
portions; pour one of these into a 1000-grain mea- 
sometimes estimated at the end of an experiment 
by Dupre’s method. This was done by removing 
the supernatant aqueous liquid with a pipette, wash¬ 
ing the solution of iodine with distilled water, trans- 
j ferring it to a stoppered bottle, and adding, with 
; vigorous shaking, weak chlorine water from a burette 
! until the colour just disappeared. The results are 
1 given in the subjoined table, and show, I think, that 
the eye has a fair claim to be trusted. When a 
number of morphia determinations have to be made 
the use of this ioclimetric process is convenient, as 
only a single daily reference to the standard is then 
needed. 
The time required for determining the morphia 
value of opium on the above plan is about two hours 
and a half. As regards accuracy and reliability, I 
may state, that so far as my experiments have gone 
—and they have not been few—the results have ap¬ 
peared, after careful scrutiny, to be nearer approxi¬ 
mations to the truth than those obtained by the 
ordinary methods by precipitation. I have, tliere- 
tsure, add 100 grain-measures of diluted sulphuric ! fore, much confidence in the process. Nevertheless, 
