25 
ESSENTIAL OIL OE MUSTARD. 
BY C. UMNEY, F.C.S. 
Although the British Pharmacopoeia has been so short a time in the hands 
of the pharmaceutist, scarcely long enough for a decided opinion to he given 
of the merits of its preparations, or for their efficacy to be tested by the 
medical profession throughout the country; a sophistication of one of its 
most potent remedial agents has been noticed, which, if allowed to pass 
without censure, may brin^ into disrepute the liniment in which it forms an 
active ingredient, as either being uncertain or varied in its action, or probably, 
in some case or other, to a loss of confidence by a patient in the dispenser of 
the adulterated medicine. 
“01. Sinapis B.P.,” is one of those very few bodies that not one chemist 
in a thousand would venture to prepare ; it would also, in the majority of 
cases, be received into stock after purchase without inspection, as it is of such 
a dangerous nature, and anything but agreeable to experiment upon, on ac¬ 
count of its penetrating odour, and instant vesication if applied to the skin. 
It will be seen therefore, that for a supply of a pure oil the pharmaceutist 
will have to depend almost solely upon the integrity of his manufacturing 
chemist. 
It may not be generally known that very little, if any, of the oil is distilled 
in this country ; our market is chiefly supplied by Germany. Two samples 
obtained in London, one from a manufacturing pharmaceutical chemist, the 
other from a commercial house, were taken for examination. The first test 
applied was the determination of their specific gravities ; one was found to 
be 1‘015, the other only ’966 (60° Fahr.). The presence of alcohol in the 
latter was immediately suspected from its having this density. It was evident 
by the following calculation that a mixture of genuine oil and spirit must 
contain at least 20 per cent, of the latter, to be of such a specific gravity. 
Sp. gr. 
4 volumes oil of mustard at 1*015 = 4*060. 
1 volume of alcohol . . *795 = *795. 
5 volumes. 4*855. 
4*855 
—-— = *971 sp. gr. of mixture (supposing no contraction in volume 
to take place). 
A portion of the suspected oil was then placed in a retort, with a thermome¬ 
ter passing into the liquid ; when heated to about 200° Fahr., the spirit 
readily distilled over, although of course contaminated with the essential oil 
which passed over in its vapour. 
Oil of mustard has a boiling-point of 298° Fahr. The great difference 
therefore, between the boiling-point of the oil and the alcohol, affords a ready 
means for their separation. To purify the alcohol for further examination is 
somewhat difficult, as the odour of the oil is not entirely destroyed, even 
when treated with ammonia and distilled, and subsequently treated with 
binoxide of mercury and re-distilled. . , 
It is to be hoped the Lin. Sinapis Comp. B.P. will have a fair trial, and 
the fraudulent adulteration of the oil of mustard be immediately discontinued, 
or the profession will soon have great and just cause to complain, and the 
compilers of the Pharmacopoeia will be ill repaid for the immense pains they 
have taken to produce so valuable a work. 
40, Aldersgate Street, E.C. 
