Symptoms of poisoning having been observed in feeding colza cakes to animals, B. Sjollema1) examined the oil obtained from the seeds of Brassica Napus, L. (B. campestris, L). After the bulk of the fatty oil had been expressed, the oil cakes were placed in hot water. When cooled, ground white mustard seed was added. The resulting mustard oil was distilled from a water bath under reduced pressure. Part of the oil floated on the surface of the aqueous distillate, another part was shaken out of the aqueous solution with ether. The yield amounted to as much as 0,8 p.c. Its density was d11/4o0,9933; aD inactive; b.p. (not corrected) about 174°. The mustard oil in question is a crotonyl mustard oil, the thiourea (white needles) of which melted at 64°. A comparison of the molecular refraction and molecular dispersion of the thioureas of allyl mustard oil and of this crotonyl mustard oil by Eykman pointed to the probable homology of these two compounds, hence the formula Csn. Ch2. CH2. CH:CH2 may be assigned to the crotonyl mustard oil of Brassica Napus. Apparently this crotonyl mustard oil is not identical with the one obtained later by Schimmel $ Co.-) from the seed of Brassica juncea, the thiourea of which melted at 69 to 70°.
l) Recueil trav. chim. des P.-B. 20 (1901), 237; Chem. Zentralbl. 1901, II. 299. *) Report of Schimmel & Co. October 1910, 83. See mustard oil, p. 524.