198 EXPERIMENT STATION RECORD. 



Gerrakd [Jour. Pharm. et Chim., ser. 6, 3 {1896), j)' 250; ahs. in Chem. 

 Ccnthl., 1890, II, No. 3, p. 135). — The reagent originally described by 

 the author' is not stable, and the following modification is therefore 

 projiosed: Ten grams of Eehling's solution and 40 gm. of water are 

 heated to boiling in a casserole and a 50 i^er cent solution of potassium 

 cyanid slowly added until the liquid is decolorized or only slightly blue. 

 Another 10 gm. of Fehling's solution is then added and the sugar solu- 

 tion run iu from a burette, the liquid being kept constantly boiling, 

 until the blue color disappears. The solution thus prepared is stable 

 through the formation of the double salt CuCyi* 2KCy. — w. h. keug. 



On the determination of glucose, Causse [Jour. Fharm. et Chim., 

 ser. 6, 3 {1896), p. 433). — In connection with Garrard's method (see 

 above), the author calls attention to the fact that in 1889 he proposed 

 the use of potassium ferrocyauid to accomj)lish the same purjDOse. — 



W. H. KRUG. 



A method for the separation of galactose and arabinose, E. 



SuBASCHOW {Ztschr. Ver. Rlihcnz. hid., 1896, pp. 270-273 ; ahs. in Ghem, 

 Centhl., 1896, II, No. 2, p. 134). — The method of separating arabinose 

 and galactose depends on the difference in the rapidity with which the 

 respective hydrazids are formed as well as the difference in solubility 

 of these compounds. 



Galactosebenzhydrazid is formed when one part of galactose is 

 heated on the water bath under a reflux condenser with the calculated 

 amount of benzhydrazid and 20 to 23 parts of 96 per cent alcohol 

 according to the reaction : C6H12O6 + C7H8N2O = CiaHisXaOe + H2O. 

 After 1^ to 2 hours the whole mass is liquid, and on cooling a small 

 amount of galactosebenzhydrazid separates. The greater portion is 

 obtained only after evaporating to ^ or J of the original volume. Ara- 

 binosebenzhydrazid is formed in a similar manner. The arabinose 

 dissolves almost immediately, and after 15 to 20 minutes the arabin- 

 osebenzhydrazid begins to separate. After further boiling for half an 

 hour and cooling the compound separates completely. — w. H. krug. 



Determination of the diastatic power of malt, W. J. Sykes and 

 C. A. Mitchell {Analyst, 21 {1896), May, pp. 122-128).— The authors 

 give the following method, which is a combination of those of Kjeldahl 

 and Lintner. The soluble starch, malt extract, and diastase solution 

 are prepared as usual. One hundred cubic centimeters of the soluble 

 starch solution and 1 cc. of the malt extract are placed in a 200 cc. 

 flask having a wide neck, well shaken, and allowed to stand 1 hour at 

 70° F. Fifty cubic centimeters of Fehling's solution is then added, the 

 mouth of the flask covered with a watch glass, and the liquid heated 

 to 98°. The flask is then placed in boiling water for 7 minutes. The 

 CU2O is collected in a Soxhlet tube, reduced with hydrogen, and the 

 copper weighed. The weight of the copper divided by 0.438 and 

 multiplied by 100 gives the diastatic power. — w. n. krug. 



1 Chem. Centbl., 1893, I, No. 9, p. 445. 



