SPICES AND CONDIMENTS. 175 



These analyses, whether regarded from a scientific or practical point of view, are 

 possessed of much interest. 



The small quantity of sugar found in mustard would, from the method of analysis 

 pursued, be included under the bitter principle and the gum with cellulose. 



Of the methods of analysis, Hassall writes : 



Estimation of myronic acid. Myronate of potash decomposes, under the influence 

 of the nitrogenous matter contained in brown mustard, into volatile oil, glucose, and 

 acid sulphate of potash. The quantity of each of these products of decomposition 

 gives, therefore, by simple calculation, the quantity of myronic acid. One hundred 

 parts of this acid yield 23.85 parts of volatile oil. From 40 to 50 grams of the mus- 

 tard farina are placed in a flask of about one-half liter capacity ; 250 c. c. of tepid 

 water are poured over it, the flask closed with a cork, and the whole is well shaken. 

 After twenty-four hours' standing the flask is connected with a Liebig's condenser, 

 and its contents are heated to boiling. Into the receiver 30 c. c. of strong ammonia 

 are poured, and the end of the condenser is dipped below the surface of the liquid. 

 Water and the volatile oil pass over, the latter at first floating in the shape of oily 

 drops on the surface of the liquid, which soon sink to the bottom, especially when the 

 liquid is gently agitated. When the distillation is finished, which is the case when 

 no more oil globules pass over, the receiver is closed with a cork and allowed to stand 

 twenty-four hours. At the end of that time all the oil is dissolved and is now con- 

 tained in the liquid in the form of thiosinnamin. This solution is evaporated on the 

 water bath in a weighed platinum basin, the residue dried and weighed. The quan- 

 tity of thiosinnamine obtained, minus one molecule of ammonia, represents the 

 amount of volatile oil. 



Estimation of the myrosin or albumen and of the sulphocyanide of sinapin. The total 

 amounts of nitrogen and sulphur contained in the mustard are next ascertained. 

 The former by combustion with soda-lime in the well-known manner, the latter by 

 deflagration of the mustard and oxidation of its sulphur in a mixture of nitrate of 

 soda and carbonate of potash. The fused mass is dissolved in water or dilute acid, 

 and the sulphuric acid contained in the solution is estimated by means of chloride of 

 barium. From these data the amounts of the inyrosin and of the sulphocyanide of 

 sinapin, the acrid principle, are thus calculated ; as much sulphur and nitrogen are 

 first deducted from the totals of these substances obtained as is contained in the 

 quantity of myrouic acid previously determined. Next, the whole of the remaining 

 sulphur and as much of the nitrogen as is required are then calculated into the acrid 

 principle ; lastly, the surplus nitrogen is calculated into inyrosin, which has the same 

 formula as vegetable albumen. But now, having got approximately the amounts of 

 the acrid principle and of the myrosin, a further calculation has to be made, since 

 myrosin contains about 1 per cent, of sulphur. This has to be deducted from the 

 total acrid principle, a corresponding quantity of nitrogen being in its turn calculated 

 into myrosin. By those acquainted with algebra it will readily be perceived that a 

 more precise calculation may be made, but the results would not, even then, differ to 

 any practical extent. 



Acting on this method, Hassall made several analyses of genuine 

 mustards of the trade and also of adulterated articles, which are here 

 presented, merely dropping the third place in decimals, which is of no 

 value. 



