NOTES ON THE PHARMACOPfEIA. 
519 
that economically ; that the utmost amount of tolerably pure sulphate of quinine 
he ever got from it was something less than 3 per cent. He had once obtained 
2-6, but then he went to work in a somewhat different way from that described 
in the Pharmacopoeia. He believed if those directions were followed it would 
be quite impossible to exhaust a pound of bark with the quantity of acidulated 
water which was there mentioned. In the first place, they were directed to take 
yellow cinchona bark in coarse powder. It appeared to him that it was utterly 
impossible that the process of percolation could be followed out with advantage 
with such substances as bark unless the bark were reduced to a tolerably fine 
powder, so as to thoroughly disintegrate and break up the cells, otherwise a large 
portion of the soluble matter -would remain locked up, as it were, in the interior 
of the cells. It seemed to him that the quantity of hydrochloric acid men¬ 
tioned was larger than was necessary ; and this, he conceived, was also a defect 
in the process. And with regard to the use of distilled water, he considered 
that an unnecessary refinement, as the very small portion of lime and other 
matters contained in ordinary water was sure to come out in the purification. 
He had found it necessary, in order to exhaust the bark, to do something in this 
way : after the first portion of the stronger solution had run off, he had an in¬ 
termediate process. It was necessary that the solvent should be in actual con¬ 
tact with the bark for some considerable time ; and if the process was carried on 
continually, an immense quantity of the acidulated water must be used to ex¬ 
haust the bark. By that means he had succeeded in practically exhausting a 
pound of bark with not much more than a gallon of water. He then evapo¬ 
rated that at a low temperature, not exceeding 150° F., keeping it nearly neutral 
by successive additions of small portions of chalk or lime, until the whole liquid 
was reduced to somewhere about a pint. By this means, nearly the whole of 
the colouring matter fell down insoluble, and was separable by filtration. After 
that, the precipitation of the alkaloid and its subsequent combination with sul¬ 
phuric acid were easy matters. There were several other matters of interest, 
but he felt reluctant to occupy so much of their time. He would only refer to 
the solution of chloride of gold. That was inserted in the Pharmacopoeia as a 
chemical test, and not as a pharmaceutical substance; but he thought the 
formula was objectionable with respect to the enormous quantity of acid which 
w r as directed, which he could only conceive had crept in by a clerical error, as it 
■was certainly six or eight times as much as was necessary to dissolve the gold. 
They were told to take fine gold reduced by a rolling machine. He supposed 
that to get fine gold they should go to the refiner’s, and he had found that what 
they called fine gold invariably contained as much as 3 or 4 per cent, of silver, 
lie considered it quite needless to reduce gold by a rolling machine. He thought 
the best method of procuring gold for their purpose was to take Australian so¬ 
vereigns,—that was what he had been in the habit of doing himself,—and to 
reduce it by solution in a Florence flask in acid. All that was required was to 
dilute the solution in order to get rid of a large amount of chloride of silver, 
which was taken up by the strength of the acid. Before he sat down he should 
like publicly to express his sense of the great kindness and courtesy with 
which he had always been met, not only on this, but on every occasion on which 
he had come in contact with Hr. Itedwood. 
NOTES ON THE PHAEMACOPCEIA. 
BY WILLIAM MARTINDALE, 
DISPENSER, AND TEACHER OF FHARMACY TO THE UNIVERSITY COLLEGE HOSPITAL. 
As we are invited to bring before these meetings suggestions regarding im¬ 
provements, or necessary alterations in the formulae of the Pharmacopoeia, I beg 
leave to draw your attention to one or two this evening. 
