PRESIDENTIAL ADDRESS, 1916 45 ABSTRACTS OF PAPERS PUBLISHED IN OTHER JOURNALS. FOOD AND DRUGS ANALYSIS. Sensitive Colour Reaction for Atropine, Hyoscyamine, and Scopolamine. R. Wasicky. (Zeitsch. anal. Chem., 1915, 54, 393-395.)-Tne reagent used is pre- pared by dissolving 2 grms. of p-dimethylaminobenzaldehyde in 8 grms. of con- centrated sulphuric acid, and then adding 0.4 grrn. of water. When a trace of either atropine, hyoscyamine, or scopolamine, is heated with a drop of the reagent, an intense red coloration develops.On removing the source of heat the colour changes to a more intense cherry-red, and then to violet-red. The reaction is obtained with as little as 0*0002 mgrm. of the alkaloids. Whilst these three alkaloids do not give a, coloration with the reagent in the cold, others-morphine and codeine -at once give a red colour ; other alkaloids, again, give reactions when warmed with46 ABSTRACTS OF CHEMICAL PAPERS the reagent, but the colorations obtained are quite distinct from that yielded by atropine, hyoscyamine, and scopolamine.w. P. s. Estimation of the Amino-Acids of Feeding-Stuffs by the Van Slyke Method. H. S. Grindley and M. E.Slater. ( J . Amcr. Chem. sot., 1915, 37, 2762-2769.) -Results of estimations of the amino-acids of certain feeding-stuffs (cot ton-seed meal, taukage, and alfalfa hay) have besn recorded previously (ANALYST, 1915, 40, 399) by the authors. Additional results are now given as follows, the figures being expressed as percentages of the feeding-stuff : Ammonia nitrogen .. . .. Humin nitrogen . . . ... Arginino nitrogen . . . ... Cystine nitrogen . . . ... Histidine nitrogen . . . Lysine nitrogen . . . ... ... Amino-nitrogen i n filtrate from bases.. . ... ... Non-amino-nitrogen in fii- trate from bases ... ... Total nitrogen . . . ... Blood Meal. 0.818 0.539 1.281 0.096 1.179 1.360 7-87 1 0.618 -3.772 Wheat. 0.380 0.199 0.173 0.029 0-036 0.055 1.029 0.294 2.195 Rollel3 Wheat.0.276 0.147 0.133 0.027 0.052 0.041 0.772 0.237 1.675 Barley 0.359 0.208 0.224 0.030 0.086 0.052 1.085 0.328 2,372 Oats. 0.289 0.218 0.251 0.026 0.095 0.077 1.136 0.174 2.264 White Soya Beans. 0.578 0.378 0.726 0.038 0.329 0.351 2.839 0.488 5.727 The high results for humin nitrogen are probably due, in part, to the presence of soluble carbohydrates during the hydrolysis of the proteins, and also to the presence of cellulose which mechanically prevents the complete hydrolysis of the proteins.There is thus a source of error in the results obtained by the direct application of the Van Slyke method to the estimation of the free and combined amino-acids and amides of feeding-stuffs. w. P. s. Estimation of Shell in Ground Cocoa.R. Wasicky and C. Wimmer. (Zeitsch. Untersuch. NahT. Genussm., 1915, 30, 25-27 ; through Bull. Agric Intelli- gence and Plant Diseases, 1915, 6, 1528- 1529.)-When examined in ultra-violet light, the powder of the cocoa bean appears violet-blue, while powdered shells have a brownish appearance. I n particular the mucilaginous tissue of the shell varies from dull white to yellowish-green, and the author’s experiments have shown that the presence of one fragment of such tissues in three prepared samples of the cocoa in- dicates the addition of 1 per cent.of shell. The samples are prepared by treating 0.01 grm. of the cocoa, with 5 C.C. of a mixture of alcohol and glycerol for an hour ; then centrifuging the mixture, and replacing the liquid by 1 C.C. of a solution of borax and glycerol, One drop of the thoroughly stirred mixture is then examined under a cover-slip in ultra-violet light by means of a special microscope, and compared with standard samples prepared from decort icated cocoa beans mixed with definite pro-FOOD AND DRUGS ANALYSIS 47 portions of shell from 1 per cent.upwards. estimating minute quantities of ergot in flours.The method is also suitable for C. A. M. Molecular Weights of Certain Vegetable Oils. H. J. Backer. (Chenz. Weekblad, 1915, 12, 1034-1040.)-The molecular weights of typical vegetable oils were cdctulated from the lowering of the freezing-point observed on dissolving The following 0.5 grm. of the oil in 15 C.C. of benzene : M = Depression (o,5y mean results were obtained : Coconut oil, 613 ; ctohune nut oil, 625 ; arachis oil, 803 ; cato seed oil, 803 ; cato seed oil (hydrogenated), 884 ; linseed oil, 796 ; maize oil, 796 ; mustard seed oil, 928 ; olive oil, 803 ; palm kernel oil, 644 ; rape oil, 892 ; castor oils, 844 and 1031; sesame oil, 800; and soya bean oil, 783. A commercial sample of blown rape oil had the following characters : Sp.gr. at 15' C., 0-958 ; [?&ID 250 c., 1.4769 ; iodine value, 65.7 ; acid value, 3-82 ; saponification value, 195 ; and molecular weight, 1355.185.6 C. A. M. Oil of the Wild-Grape Seed ( Vdtz's R&pCtrz'ct). G. D. Beal and C. K. Beebe. (J. Ind. and Ercg. Chem., 1915, 7, 1054.)-The crushed seeds of the wild-grape, on extraction with lighrt petroleum spirit, yielded 19.38 per cent. of a greenish amber- coloured oil with a peculiar amid odour and taste like castor oil, The examination showed : Sp.gr. at 15' C., 0.9425 ; [ n ] ~ 1 5 O c., 1.4781 ; saponification vdue, 187.8 ; iodine value, 76.47 ; acetyl value, 61-29 ; insoluble, 90.0 per cent. ; neutralisation value of fatty acids, 173.4. Total fatty acids : liquid, 95 per cent. ; solid, 5.0 per cent. ; iodine value of the acids : liquid, 91.8; solid, 3.12 ; mean moleculax weight, 268.6.The chemical characters of this oil all tend to place it in the group with the other oils of the grape family, and with castor oil, by which the group is headed. J. F. B. Resins in Hops from Various Geographic Localities. G. A. Russell. (J. Ind. and E y . Chem., 1915,7, 1033-1035.)-The soft resins were extracted by maceration and percolation with light petroleum spirit.Drying the extract in vacuo did not yield good results, as it showed a continuous loss of weight; concordant results were obtained by allowing the last trace of solvent to evaporate spontaneously, and weighing as soon as this solvent was removed. In 8 portion of the product the co-extracted wax was estimated by redissolving in light petroleurn and precipitating the wax by methyl alcohol.The hard resin was estimated by extracting the previously treated residue from the soft resins with ether in a Soxhlet apparatus for about six hours and drying the evaporated extract in an electridly heated omn for thirty minutes. Results showed that a single sample weighing 10 grms., whether selected at random or selected from perfect oones, does not give a correct indication of hhe amount of soft resins in a quantity of hops.The average of a number of estima- tions in samples weighing 10 grms. picked at random gives a true indictation, as likewise does one large representative sample of about 1,500 grms. taken for extrac- tion. The methods outlined above give accturate comparable results. The yield of soft resins varies from season to season in the same and different localities, making48 ABSTRACTS OF CHEMICAL PAPERS necessary the determination of the percentages of soft resins in every bale of hops at the time it is used. The time of storage plays a large part in the variations of per- centage of soft resins. The percentage of ash in hops varies in samplee from different localities, but remains approximately the same in samples from the same locality from year to year. J. I?, B.