December 9,1871.] THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
465 
rule be adhered to of always using the same de¬ 
nomination of weight or measure throughout a pro¬ 
cess ; and when measure as well as weight is indi¬ 
cated in the same process, of using a measure that 
corresponds with the unit of weight. The quan¬ 
tities used in testing are always such as easily admit 
of the application of this rule, and, in other respects, 
only a few slight alterations are generally required. 
The following examples will serve to illustrate the 
mode of treating cases of tliis sort. 
Vinegar. 
Characters and Tests. —A liquid of a brown colour and 
peculiar odour, specific gravity 1-017 to T019. 500 
measures of it require at least 451 measures of the volu¬ 
metric solution of soda, corresponding to 5-4 per cent, of 
acetic acid (HC 2 H 3 0 2 ). If mixed with by measure 
of solution of chloride of barium, and the precipitate, if 
any, separated by filtration, a further addition of the test 
will give no precipitate. Sulphuretted hydrogen causes 
no change of colour. One fluid ounce or 28-340 cubic 
centimetres, contain 24 grains, or 1-55 grams, of acetic 
acid (HC 2 H 3 0 2 ). 
Hydrochloric Solution of Arsenic. 
Characters and Tests .— A colourless liquid, having an 
acid reaction. Specific gravity 1-009. Sulphuretted 
hydrogen gives at once a bright yellow precipitate. 
400 measures of it boiled for five minutes with 20 parts 
of bicarbonate of soda, and then diluted with 2000 mea¬ 
sures of distilled water, to which a little mucilage of 
starch has been added, does not give with the volu¬ 
metric solution of iodine a permanent blue colour until 
808 measures have been added, corresponding to 1 part 
of arsenious acid in 100 measures of the solution. 
One fluid ounce, or 28-349 cubic centimetres, corre¬ 
sponds to 4 - 375 grains, or 0 - 283 gram, of arsenious acid. 
In this case I have assumed that the process has 
been so altered as to jneld a 1 per cent, solution. 
I think I have now referred to the various condi¬ 
tions under which the substitution of proportional or 
relational numbers for specified weights and measures 
might be effected. I submit the proposition to the 
judgment of those members of the medical and phar¬ 
maceutical bodies who are anxious to make the 
British Pharmacopoeia a credit to this nation, and 
available for use in all other countries. 
\_The discussion upon this paper is reported at p. 476.] 
A METHOD FOR THE ESTIMATION OF 
MORPHIA IN OPIUM.* 
BY JOHN T. MILLEU. 
The narcotic power of opium is mainly owing to 
morphia, the proportion of which in different speci¬ 
mens is subject to great variation. As the appear¬ 
ance of the drug affords no clue to its strength, 
the pharmaceutist can solve that problem only by 
the emplojnnent of chemical means. A morpliio- 
metric method at once “ ready, easy, accurate and 
precise,” is still, I believe, as it was when Pereira 
wrote, a desideratum. 
The process given in the British Pharmacopoeia 
is, perhaps, as good as any of the kind, yet it is 
tedious, and, judging from my own experience, un¬ 
certain. Not being satisfied with it, I resolved to 
try whether a method of moderate accuracy and 
readiness could be based on the reduction of iodic 
* Read at the Evening Meeting of the Pharmaceutical 
Society of Great Britain, l)ec. 6, 1871. 
acid by morphia. The scheme did not seem very 
promising, for that acid is decomposed by many or¬ 
ganic bodies besides morphia; but as their action is, 
for the most part, much slower than that of the 
alkaloid, I thought it might be possible (supposing 
such bodies to be present) to separate with suffi¬ 
cient sharpness, their effect from that due to the 
morphia. It will be seen presently, however, that 
the chief difficulty met with was not of the kind 
anticipated. 
With a weighed quantity of the sample to be 
tested, a solution was prepared as free as possible 
from resinous, mucilaginous and colouring matters ; 
but it was not considered necessary to remove any 
of the opium principles, as they do not, with the 
exception of morphia, decompose iodic acid. To a 
certain volume of this solution some aqueous iodic 
acid was added, and after the lapse of a few minutes 
the liberated iodine was washed out by shaking the 
mixture with carbon disulphide. The sample colour 
thus produced was then compared with another— 
the standard colour —prepared in the same manner, 
but from a solution of morphia of known strength; 
and their intensity was equalized by adding carbon 
disulphide to the deeper. From the data thus ob¬ 
tained the percentage of morphia in the sample was 
calculated. 
When a number of specimens had been thus exa¬ 
mined, they were next tested by the B. P. process. 
The results obtained were higher—sometimes con¬ 
siderably higher—than those yielded by the former 
method. However, as the precipitates were not 
pure, each was washed with half a fluid ounce of cold 
chloroform, dried and reweighed. All had lost more 
or less in weight; but very little of the matter dis¬ 
solved out could be morphia, as a fluid ounce of chloro¬ 
form takes up only about 0T grain of that substance. 
A portion of each washed precipitate was next accu¬ 
rately weighed off and made into a solution similar 
to the standard, with which it was carefully compared 
in reducing power, and the amount of real morphia 
in the precipitate thereby determined. The accord¬ 
ance of the two series of figures was now much 
closer than before ; but a suspicion arose that some 
of the reduction results were too low, and soon 
reached certainty. To clear up this point numerous 
experiments were tried, only a few of which need 
be mentioned :—- 
1. Some narcotine was added to the standard 
morphia solution, then iodic acid, and after the mix¬ 
ture had stood a few minutes, it was shaken with 
carbon disulphide. The feeble colour of the latter 
showed plainly that it contained less than the usual 
quantity of iodine. 
2. The experiment was repeated, but with this 
difference, viz. the shaking with carbon disulphide 
was performed immediately after adding the iodic 
acid. The full colour was now obtained, the libe¬ 
rated iodine having been seized by the disulphide 
before the secondary reaction could take place. 
3. Similar ■experiments were tried with codeine, the 
invariable result being a diminution in the amount 
of iodine set free. 
4. Thebaine was found to act in the same direction 
as codeine. 
5. Iodine water, when added to a slightly acid 
solution of papaverine, produces a red-brown pre¬ 
cipitate, which gives with chloroform a yellow or 
brown solution; but carbon disulphide abstracts the 
iodine from the compound and liberates the papave- 
