SEMEN SINAPIS NIGR^. 67 



nitrate. These cliemists obtained sinigrin from the seeds in the pro- 

 portion of 0-5 per cent. ; Will and Korner got 0'5 to 6 per cent. The 



extraction of the substance is therefore attended with great loss, as the 

 minimum yield of volatile oil, 0'42 per cent, indicates 2-3G of potassium 

 myronate. 



The aqueous solution of myrosin coagulates at 60° C. and then 

 becomes inactive : hence mustard seed which has been heated to 100° C. 

 or has been roasted yields no volatile oil, nor does it yield any if 

 powdered and introduced at once into boiling water. The proportion of 

 myrosin in mustard has not been exactly determined. The total amount 

 of nitrogen in the seed is 2-9 per cent. (Hoffmann) which would corre- 

 spond to 18 per cent, of myrosin, supposing the proportion of nitrogen 

 in that substance to be the same as in albumin, and the total quantity 

 of nitrogen to belong to it. Sometimes black mustard contains so little 

 of it, that an emulsion of white mustard requires to be added in order 

 to develop all the volatile oil it is capable of yielding. 



An emulsion of mustard or a solution of pure sinigrin brought into 

 contact with myrosin, .frequently deposits sulphur by decomposition of 

 the allyl sulphocyanide, hence crude oil of mustard sometimes contains 

 a considerable proportion (even half) of Allyl cyanide, C'^ffN, distin- 

 guished by its lower sp. gr. (0-839) and lower boiling point (118° C). 



The seeds, roots, or herbaceous part of many other plants of the order 

 Cruciferce yield a volatile oil composed in part of mustard oil and in part 



of allyl sulphide CH^S - %^, I S, which latter is likewise obtainable 



from the bulbs of garlic. Many Cruciferce afford from their roots or seeds 

 chiefly or solely oil of mustard, and from their leaves oil of garlic. As 

 to other plants, the roots of Reseda lutea L. and M. luteola L. have 

 been shown by Volhard (1871) to afford oil of mustard.' The strong 

 smell given off by the crushed seeds or roots of several Mimoseae, as for 

 instance, Alhizzia lophantha Benth. (Acacia Willd.) is perhaps due to 

 some allied compound. 



Hie artificial preparation of mustard oil was discovered in 1855 by 

 -^inm, and at the same time also by Berthelot and De Luca. It may be 

 ootamed in decomposing bromide of allyl by means of sulphocyanate 



of ammonium : 



'ff Br . SCN(NH') - NH^Br . CH 



. . -^he liquid C'H 



It IS 



th^^ gently warmed with a little alcoholic potash, and then acidulated, 

 e red coloration of ferric sulphocyanate is produced on addition of 



dUn •^^'^ pf iron, but by submitting the sulphocyanate of allyl to 



stuiation it is at once transformed in the isosulphocyanate, i.e. in 



^ustard oil; the latter is not coloured by ferric salts, but it would 



suhT^ ^^at in the cold emulsion of mustard, even at 0°, a little 



idiocy anate makes also its appearance. 



^viustard submitted to pressure affords about 28 per cent.' of a mild- 

 atid ' ^P^^^^^^S' non-drying oil, solidifying when cooled to - 17-5° C., 

 or p^^^^.^^^^^g of the glycerin compounds of stearic, oleic and Erucic 



I fee also Hadi 



(T^H^ 



I havA ^^'^ ^rmorac'm, p. 68. per cent, by means of boiling ether, 



^e obtained aa much as 33-8 P. A. F. 



