376 EXPERIMENT STATION RECORD. 



alcohol and was found to be identical with the diastatic achroodex- 

 trin isolated by Lintner and the achroodextrin found in beer wort 

 by Mittelmeier. It could not be crystallized, and by the freezing 

 method gave the molecular weight 1,962, corresponding to the formula 

 (C,2H2oOin),iH,0=l,9G2. 



Prejmration of the disaccharid. — All fractions remaining from the 

 preparation of the dextrin whose rotation did not exceed +145° were 

 united and the disaccharid separated by precipitation with alcohol and 

 dialysis. The dialysate gave an osazone consisting of light yellow 

 needles, 0.32 gm. of which, dissolved in 100 cc. absolute alcohol, gave 

 [a] D =+54o. The melting point was 184 to 186°. Although maltosa- 

 zone has [a] D = +61° and a melting point of 202 to 206°, the disac- 

 charid of honey dextrin is probably maltose. — w. h. kritg. 



Contributions to the analysis of honey, E. Beckmann {Ztschr. 

 analyt. Chem,, 35 {1890), Ko. 2, p.263 ; ahs. in Cheni. Ztg., 20 [1896), ¥o. 

 70, Iiepert.,p. 221). — Konig's method for the detection of glucose in honey 

 does not alwaj's yield reliable results, as many honeys can contain from 

 15 to 20 per cent of starch sirup or starch dextrin without showing 

 dextrorotation after precipitating with alcohol. The author uses ace- 

 tone or methyl alcohol and tinds that all, even dextrorotatory honeys, 

 are tahen up by these solvents, while a honey mixed with glucose sirnp 

 gives a copious precipitate of dextrinous substances. The reaction of 

 such a honey with an iodin solution is also characteristic. It becomes 

 intensely red, or even violet, while a pure honey is colored only slightly. 



To detect adulteration witli glucose the following method is proposed: 

 Five cubic centimeters with a 20 per cent honey solution is mixed with 3 

 cc. of a 2 per cent barium hydrate solution and 17 cc. of methyl alcohol 

 and well shaken. The presence of even slight amounts of glucose,or glu- 

 cose sirup, is shown by the resulting turbidity. When a clear solution of 

 honey can not be obtained, the polarization must be united with this 

 test. — Av. n. KRua. 



The determination of sugar in chocolate, Kocques [Ann. Chim. 

 anal, appluj., 1 {1896), p. 288 ; ahs. in Chem. Zf(/.,20 {1890), N^o.72,Repert., 

 p. 229). — Fifteen grams of the powdered chocolate is heated to 40° C. 

 with 90 cc. of water until the cocoa butter has melted, and the mixture 

 is well stirred. Fifteen cubic centimeters of a 10 per cent basic lead 

 acetate solution is then added, the li<]uid filtered, and the lead removed 

 by adding to 70 cc. of the filtrate 30 cc. of a solution consisting of 20 cc. 

 of a 20 per cent sodium sulphate sokition and 10 cc. of glacial acetic acid. 

 This gives a very clear filtrate, which can be easily polarized. — w. ii. 



KRUG. 



The estimation of tannin, B. Weiss {Der Gerber, 22 {1890), p. 02; 

 abs. in Jour. 8oc. Chem. Ind., 15 {1890), No. 8, p. 020).~T\\(i author finds 

 that it is essential to use a constant weight of extract dissolved in 

 a constant volume of water and to work at the same temperature. 

 It is shown that hide powder which has been washed and dried as 



