NOTES ON SCIENTIFIC RESEARCH. 59 
In conformity with Griitzner’s method‘), mustard oil is not oxidized direct, but 
first transformed, with the aid of ammonia, into thiosinamine, which is then oxidized 
with sodium peroxide. Wehrmann allowed the sodium peroxide to act at first in the 
cold and then heated the mixture. For 1 g. of mustard oil he used 5 g. of sodium 
peroxide. The method affords very good results and is easily carried out. 
In order to estimate mustard oil, one may likewise determine its content of 
nitrogen, for instance after Kjeldahl. For this purpose, Wehrmann weighed pure 
mustard oil in small bulbs, which he had made himself from a glass tube and sealed 
after having filled them. He broke. such a bulb, in a vessel as recommended by 
Kjeldahl, below the required sulphuric acid, destroyed the mustard oil in the usual 
way and then determined the ammonia formed. From the quantity of nitrogen deter- 
mined from the ammonia he then calculated the corresponding amount of mustard oil. 
The values found were fairly good, but the process is too complicated and suitable 
only for pure mustard oil, not for the evaluation of mustard oil in mustard seed. 
Passon?) found that mustard oil may be distilled from oil-cake, mustard powder 
or mustard paper into glacial acetic acid, in which solution he determined the content 
of nitrogen according to Kjeldahl. One adds some powdered zinc or iron to the 
glacial acetic acid in the receiver, so as to bring about a partial reduction of the 
mustard oil to the amine. In order to avoid losses of mustard oil during the distil- 
lation, a vessel with a little concentrated sulphuric acid is connected with the receiver © 
containing the glacial acetic acid. The solution of mustard oil in glacial acetic acid 
and the concentrated sulphuric acid are then united in a flask of the kind recommended 
by Kjeldahl for the purpose, and the content of nitrogen is determined in the usual way. 
Wehrmann tested this method on a solution of mustard oil in alcohol and recovered 
in two experiments 98 and 99.6 p.c. of the mustard oil employed. As may be seen, 
the process gives good results, but it is very intricate, takes time and requires much 
practice. 
The method recommended by Jorgensen?), after which not the mustard oil but the 
thiosinamine, obtained with the aid of ammonia, is determined according to Kjeldahl, 
has been examined by Wegener, who in two instances found 96.98 and 97.8 p.c. of 
the mustard oil used. 
Wehrmann concludes from the results of his investigations that out of the methods, 
based upon oxidation of the sulphur, Grtitzner’s is the most useful. As regards the 
methods for determining the sulphur as metallic sulphide, Dieterich’s gives the best 
results, and the best titrimetric process is that prescribed by the German Pharmacopoeia, 
5th edition. . 
Wegener verified some other tests, which Wehrmann had not taken into con- 
sideration. 
Following Pleijel’s method’), Wegener found 98.21, 97.82 and 98.0 p.c. of the 
mustard oil employed. 
In the commentary to the German Pharmacopoeia, Fischer and Hartwich indicate 
Gadamer’s prescription with the addition that the mixture of distillate, ammonia and 
N/10 silver nitrate solution ought to be heated to 80° after a 24 hours’ standing. 
The results of three experiments were 98.27, 98.56 and 97.98 p.c. 
Holz*) recommended the method of the German Pharmacopoeia, 4 edition, with 
the modification that the mixture of distillate, ammonia and silver nitrate solution 
1) Arch. der Pharm. 237 (1899), 185; Report October 1899, 37. — %) Zeitschr. f. angew. Chem. 9 (1896), 
~422. — *%) Chem. Zentralbl. 1898, Il. 927. — *) Farmac. Revy 1907, 204; Report October 1907, 64. — 5) Ver- 
Ofentl. a. d. Gebiete d. Militér-Sanitdtswes. 1915, number 29. 
