ON THE ASSAY OF ALKALOIDS IN EXTRACTS. 
273 
a soluble form, is poured into a long test-tube, to it is added an excess of bi¬ 
carbonate of potass, and the whole shaken with four or five times its volume 
of pure ether. The recovered ether washed with acidulated water yields 
to it the alkaloids it had abstracted. The weak point of the process is this, 
that morphia is exceedingly insoluble in ether, in fact, unless when recently 
precipitated and in the hydrated state, it is practically insoluble in that fluid. 
M. Yalser has fortunately hit on a solvent that deprives the process of all 
ambiguity. He treats the liquor that has been washed with ether with a 
second washing with acetic ether. In this fluid morphia is readily soluble, 
and rises with it to the surface, whence it is obtainable in a pure state. It 
would also be preferable to use chloroform when strychnia is present. In 
fact the process is not mechanical, but demands in each case some peculiarity 
of treatment that must be left to the skill of the operator. 
I think it can hardly be expected of a pharmaceutist that he shall, for the 
purpose of verifying his extracts, go through the details of this long and ex¬ 
pensive process ; for it requires a liberal consumption of alcohol and ether, 
as well as the expenditure of considerable time, to arrive at correct results. 
Nevertheless, I am unable to recommend a better or shorter, applicable in all 
cases. I will, however, shortly relate some experiments in that direction, 
leaving others to improve what I have not been able to perfect. 
Dr. Attfield’s paper on the solution of alkaloids in oils, wherein he recom¬ 
mended the alkaloid to be first united with oleic acid, suggested to me at the 
time the possibility of applying that acid to the elimination of the active 
principles of extracts. Oleic acid dissolves all alkaloids, is remarkably dis¬ 
criminative in its solvent power, is very cheap, and neither liable to loss from 
evaporation nor demanding thgt care in use exacted by such volatile solvents 
as alcohol and ether. 
In experimenting on its applicability, I have added known quantities of 
alkaloid to extract of cabbage, which I had ascertained by previous trials to 
contain no body capable of being mistaken for the alkaloid. But I will first 
describe some blank experiments on pure solutions of alkaloid. My plan of 
proceeding was to take 100 grain measures of the alkaloid (hi the case I am 
describing, strychnia— tuVo equivalent or ‘334 grain), exactly neutralize the 
free acid it contained, then acid 10 grain measures of volumetric ammonia, 
and about ^ ounce of oleic acid. The mixture when shaken formed an emul¬ 
sion which was heated for a few minutes by water-bath with occasional agi¬ 
tation. The vessel was kept tightly closed to prevent loss of ammonia. Re¬ 
moved from the bath and cooled, it was treated with 10 grain measures of 
volumetric oxalic acid. This combined with and exactly neutralized the am¬ 
monia, and so destroyed the emulsion. The fluids were encouraged to sepa¬ 
rate by a second immersion in the bath. The oily stratum removed by pipette 
was washed with dilute hydrochloric acid, and the washings estimated volu- 
metrically by the iodohydrargyrate. I recovered in this way fb of what I 
had inserted, and obtained the same result when quinine was substituted for 
strychnia. On comparing these figures with those obtained by the use of 
ether, I found them identical, but the time consumed by one was more than 
double that of the other, viz. oleic acid, one hour, ether, twenty-five minutes. 
On the other hand, the cost of one was nil, the other involved a certain un¬ 
avoidable loss of ether. With aqueous solutions of extracts this comparison 
would be more favourable to the oleic acid, as it rises from such mixtures 
more readily than does ether, which gives much trouble by forming ether- 
bubbles, that are to be broken up by long standing, or addition of alcohol, 
which involves a loss of ether. 
With morphia the process did not succeed. The acid removed only the 
suspended alkaloid, leaving untouched that portion in watery solution. This 
VOL. vi. x 
