268 BRITISH PHARMACEUTICAL CONFERENCE. 
I thought this fact might have a bearing on some of the awkward circum¬ 
stances that have occurred in the dispensing of prescriptions containing 
phosphoric acid and iron salts, one of which is mentioned by Mr. Deane 
(Pharm. Journ. vol. iv. p. 508), and one which came to my own knowledge 
where a prescription ordering, Tinct. Eerri Mur. 5ss, Acid Phosph. Dil. ^ss, 
Aqua ad ^xij, was made turbid at one place and clear at another. The case 
mentioned by Mr. Deane is however, as he found, independent of any pre¬ 
sence of metaphosphoric acid, strength and mode of mixing being the causes 
of the difference of appearance in the mixtures in question. The other case 
is so dependent. The acid which produced the turbid mixture contained the 
monohydrate. In experimenting on this, I found sesquichloride of iron to 
be equally as delicate a test for this hydrate as nitrate of silver. It gives 
with it a yellowish-white precipitate, insoluble in free acid. I was induced, 
on noticing the above, to see how long glacial phosphoric acid, when simply 
dissolved in cold water, would retain any monohydrate. Maisch (Pharm. 
Journ. vol. iii. p. 278), as already mentioned, shows that the conversion is not 
so rapid as was supposed, but found that at their American summer tem¬ 
perature it was complete in two or three weeks. In the beginning of De¬ 
cember, I made some dilute acid, L. P. strength, from glacial, by solution 
in cold water. This gave a white precipitate with nitrate of silver, also 
with sesquichloride of iron, as noted above. I tried this in the same way, 
at intervals, to the end of March, nearly four months,—the turbidity of the 
iron mixture certainly somewhat decreasing, but unmistakably present. I 
then, from other engagements, did not try it again till the middle of July, 
then it gave a clear mixture with iron and also no precipitate with nitrate of 
silver. 
Bradford , Yorkshire. 
ON THE ASSAY OP THE ALKALOIDS IN PHARMACEUTICAL 
EXTRACTS. 
BY THOMAS B. GROVES, F.C.S. 
(Read at the Bath Meeting of the British Pharmaceutical Conference, Sept. 1864.) 
The proneness to change, characteristic of all watery extracts, added to the 
frequent mal-preparation and sophistication of those devoted to medicinal 
uses, point to the desirability of inventing a method by which their degree 
of activity may be readily ascertained ; and, although I have strong doubts 
of the possibility of arriving at exact results by a ready process, I hope my 
experiments in that direction may not be deemed wanting in interest or other¬ 
wise undeserving attention. 
The subject naturally divides itself into two parts—the preliminary pro- 
cesses for getting the active part of the extract into a state adapted for esti- 
timation ; tec estimation itself. 
I am co npelled, as it were, to put the cart before the horse, by taking up 
the latter peint first, in order to decide on the kind and degree of preparation 
necessary icr a near approach to accuracy. 
The ease and nicety of well-devised volumetric methods are so well appre¬ 
ciated by all, that it would be superfluous to insist on the desirableness of 
a Pplyi n £b if possible, some such method to the estimation of the alkaloids. 
Professor Mayer, of New York, has recentl} r made that attempt, having 
published his results in the 1862 volume of the Proceedings of the American 
Pharmaceutical Association. The same subject was also very ably and fully 
treated in the same year by M. Valser, whose thesis, presented to the autho¬ 
rities of the superior school of pharmacy of Paris in order to obtain the title 
