478 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS, 
[December 9, 1871 
tainly appeared to be rather satisfactory. The only 
question which arose in his mind was as to the use of 
the eye of the operator in arriving 1 at a conclusion. 
Different operators might arrive at different conclusions 
on the same specimen, and some people could not distin¬ 
guish colours at all. 
Professor Attfield said Mr. Miller did depend upon 
the colour of his solution of iodine in disulphide of car¬ 
bon ; but his experiments showed that his eye could be 
trusted, for he had performed other experiments in 
which he did not trust his eye, but estimated the iodine 
by another method. Moreover, Mr. Miller referred to 
the possibility of any operator not being able to distin¬ 
guish accurately the differences in nearly similar shades 
of colour, and showed that this difficulty could be con¬ 
trolled, if an operator wished to control it, by another 
method,—Dupre’s method. It occurred to him that, if 
there was any objection to this process of Mr. Miller, it 
was not exactly the usual one against volumetric 
methods, viz. that it would occupy far more time to 
prepare standard solutions than to make a gravimetric 
determination, because, although that was a very tan¬ 
gible and valid objection in many cases, still operators 
had frequently to examine a great number of samples, 
and then the volumetric method was immensely useful, 
and saved an enormous amount of time. That was not 
an objection which seemed to him to attach to Mr. 
Miller’s method; but it was this, that this process most 
peculiarly seemed to depend more than most volumetric 
processes on the observances of a great number of 
conditions, and, therefore, it was not likely to be so 
popular a process as when a volumetric method de¬ 
pended upon some definite constant reaction. How- 
ever, he thought the Society was greatly indebted to 
Mr. Miller for the labour which he had undergone in 
carrying out this investigation, because there were many 
other points of view from which it was excessively in¬ 
teresting. The nature of the reaction was peculiarly 
so. He believed that many years ago the reaction of 
iodic acid on morphia was investigated, but without any 
definite results. There was enough done, however, to 
show that by careful working the nature of this reaction 
might probably be made out; and if this paper of Mr. 
Miller’s should lead him, or induce any other gentleman, 
to continue the investigation and ascertain what the 
reaction actually was between iodic acid and morphia, and 
the exact conditions under which the reaction occurred, 
then his process might have a considerable value, for 
he supposed every one who had attempted to estimate 
the amount of morphia in opium (at all events any 
number of times) would have found a very great deal of 
difficulty, and would hail with pleasure any suggestion 
which would be likely to economize the time, and enable 
him to get at better results than he could now obtain by 
the current processes. 
Mr. Williams said ho thought the paper was a very 
important and interesting one. He wanted to ask this 
question:—Was he to understand that the iodic acid 
solution was merely made from 200 grains of iodine 
mixed with six ounces of water, after a very complicated 
chemical process, in which the iodate of barium was 
thrown down and washed, and afterwards decomposed F 
Was there no other way of standardizing that solution ? 
Professor Attfield : Yes, by a weighed quantity of 
morphia. 
Mr. Williams said it seemed to him that it should be 
standardized. He thought there were the germs of a 
good process, but it required working out still more; 
and the point with regard to the standard character of 
the iodic solution was one that must be decided in a 
very different way from the process given in the paper. 
Professor Redwood said that one obj ection which seemed 
to attach to this process, and one which Mr. Miller had, in 
fact, himself indicated in his first experiments, was that 
the iodine first set free was soon lost to a great extent. 
Mr. Miller had attempted to overcome that difficulty, 
and probably he had succeeded, in some degree, by 
removing the iodine from contact with the organic matter 
in the solution as quickly as possible. 
Professor Attfield : In half a minute. 
Professor Redwood said that, although it might be 
removed in half a minute, still there was a race between 
two reactions. They knew what iodine as well as chlo¬ 
rine would do when brought into contact with organic 
substances. There was a loss of free iodine, and the 
extent could not be known, and the whole of the iodine 
did not at last contribute to the colour. That seemed to 
be a fundamental objection ; and any of those persons 
who had had experience in testing for the presence of 
starch in complex organic liquids by means of iodine, 
must have met with frequent cases in which they could 
get no reaction at all, the iodine being disposed of as 
free iodine before even the colour-test of starch could 
be produced. He had met with cases of that descrip¬ 
tion in testing for the presence of starch in sarsa¬ 
parilla solutions, and other complex organic liquids. 
The reason why Mr. Miller could not at first get any 
results that were reliable was that the iodine was left- 
in the presence of organic matter, and was so disposed 
of, and hence did not contribute to the colour. This 
objection to the process of Mr. Miller might not be 
so serious as it appeared; but he (Professor Redwood) 
coofessed that he should feel greater reliance on a 
direct method by which the morphia was got out, so 
that it could be weighed and tested, than on an in¬ 
direct method of this description, more especially 
when it was considered that although the object of 
the process now described was to economize time and. 
to save trouble, it seemed to be a more complicated pro¬ 
cess than that given in the Pharmacopoeia. He might 
say that he had himself been working upon this subject 
for a considerable time, and had made a great number 
of determinations of the quantity of morphia in opium, 
by the several known processes, including that described 
in the Pharmacopoeia. He should hail with groat satis¬ 
faction a good volumctrical method of estimating mor¬ 
phia, but he feared that the process of Mr. Miller was- 
rather an untrustworthy one. He (Professor Redwood) 
had arrived at the conclusion that the process given iix 
the Pharmacopoeia was the best. He admitted with. 
Mr. Miller that the Pharmacopoeia process was some¬ 
what tedious, but he thought that the details of it 
might be modified so as to render it less tedious. The. 
time occupied was taken up chiefly in percolating and 
exhausting the opium by percolation. The process 
might perhaps be improved in that respect. 
Mr. Allchin said that perhaps he might be allowed 
to describe a process which he had followed for some 
years in the estimation of morphia in opium. It con¬ 
sisted merely of exhausting the opium with water, and 
evaporating down the aqueous solution. He took 100 
grains, and evaporated the solution to an ounce and a half. 
He then dissolved a drachm of sesquicarbonate of am¬ 
monia, and mixed the two solutions; collected the pre¬ 
cipitate on a filter, and washed it until the solution, 
ceased to pass through coloured. He found that opium, 
gave about 21’5 grains of impure morphia. He was aware 
that in some cases this would not be a proper way of esti¬ 
mating opium, but it would be very easy for those who 
prepare opium to introduce a little chloride of calcium to 
procure a corresponding precipitate. He believed, how¬ 
ever, it was a very correct way of estimation. At the 
time opium was dear he obtained various specimens, and 
tested them by this process, and, curiously enough, each, 
result corresponded with the price of the opium, proving 
to him that there was a very correct estimate in tho 
market of the value of the opium. If the sample was. 
likely to contain lime or some salt, it would be necessary 
to carry the process one step further; perhaps liquor 
potassre might be U3ed to dissolve out the alkaloid, leaving 
the inorganic salt behind. 
Mr. Gtroves said that there was no doubt that Professor 
