12 EXPERIMENT STATION RECOED. 



The sulphur compounds of the onion (Allium cepa), ^V. D. Koopeb {Ztsehr. 

 Untersuch. Nahr. u. Genussmtl., 19 (1910), No. 10, pp. 569-511; abs. in Chcm. 

 Abs., Jf {1910), No. 17, pp. 2337, 2338 ) .—Considerable quantities of thiocyauic 

 acid were found in the weakly acid juice of freshly expressed onions. The allyl 

 ester of the acid was also present, but no allyl aldehyde. The author gives a 

 brief review of the existing literature on the subject, and reports his analyses 

 of onions. He found 0.047 per cent of mustard, oil and 0.015 per cent of sulphur 

 in organic combination. 



The erepsin of the cabbage (Brassica oleracea), Alice F. Blood {Join: 

 Biol. Cheiii., 8 {1910), No. 3, pp. 215-225). — "An active solution of a vegetable 

 erepsin can be prepared from the wbite cabbage by the ammonium sulphate 

 method. This solution deteriorates only slowly if kept in a cool place under 

 toluene. Cabbage erepsin splits tryptophan from Witte's peptone and casein, 

 .•md tyrosin from peptone 'Roche.' It clots milk and liquefies gelatin. It does 

 not digest fibrin, coagulated egg white, or edestiu in neutral, acid, or alkaline 

 solution, or in the presence of HCN. It does not liberate any tryptophan from 

 the protein precipitated with it from the cabbage by ammonium sulphate. The 

 erepsin is active over a considerable range of acidity and alkalinity, but is 

 inhibited by a concentration of hydrogen ions corresponding to acidity to methyl 

 orange. No evidence was obtained that hydrolysis is favored by high temper- 

 atures or that It is greatly accelerated by HCN." 



The presence of some organic bases in Boletus edulis, K. Yoshimuea 

 {Zfschr. Untersuch. Nahr. u. Genmsmtl., 20 {1910), No. 3, pp. 153-155) .—From 

 the analysis of 1 kg. of air-dry fungus there was obtained adenin 0.12 gm., 

 liistidin 0.14 gm., and trimethylamin 0.15 gm. Arginin and cholin were not 

 found. 



The composition of malt vinegar, E. Russlll and T. Tl. Hodgson {Analyst, 

 35 {1910), No. 413, pp. 3//6-3//8).— Analyses of 13 samples of vinegar, 9 of which 

 were genuine, 2 wood vinegar, 1 prepared without malt, and 1 of doubtful origin 

 but sold as malt vinegar, are reported. From these analyses it appears that 

 pure malt vinegar varies but little as to the total solids (from 1.47 to 3.15 per 

 cent), these being higher than those contained in wood vinegar. The actual 

 acetic acid present varied from 3.85 to 6.36 per cent. The ash content was 

 from O.IS to 0.6 (higher than in wood vinegar), the phosphates from 0.047 to 

 0.092 per cent. Phosphates were absent in wood vinegar. The vinegars made 

 without malt showed very little difference in constituents from those made from 

 malt, except possibly in the phosphorus content, and could easily have passed 

 the United States standard as genuine. The alkalinity of the ash was found 

 to be of no value in differentiating between wood and malt vinegars. 



An accurate method, for estimating the caffein in tea and in green and 

 roasted coffee, J. Burmann {BhI. Soc. Chim. France, //. ser., 7 {1910), No. 6, 

 pp. 239-21,4, flfj. 1; abs. in Cliem. Ztg., 34 {1910), No. 92, Repert., p. 380, fig. 1).— 

 To 5 gm. of the air-dry, fat-free substance 150 cc. of chloroform and 5 gm. of 

 a 10 per cent solution of ammonium hydrate are added. The solution is filtered 

 and the filtrate concentrated in an Erlenmeyer flask, dried, and weighed. The 

 residue, which has a dark brown color, is then dissolved in a little chloroform, 

 brought into a glass tube which has two constrictions (illustrated in the origi- 

 nal article), the chloroform evaporated on the water bath, and the residue 

 finally dried in vacuum at 100° C. In the lower constriction of the tube is 

 l)laced an asbestos plug, and in the upper one a cotton plug. The whole appa- 

 ratus is then put into a paraffin bath and heated at from 210 to 240°. After 3 

 hours, when the caffein has sublimed, the portion of the tube below the lower 

 constriction is cut and the caffein therein taken up with chloroform, dried, and 



