Janttaet 6, 1922] 



SCIENCE 



27 



The manufacture of chemically pure dextrose: 

 C. E. G. PoRST AND N. V. S. MuMFORD. The de- 

 velopment of a method of manufacturing chem- 

 ically pure dextrose using crystallization from 

 water only is described. The first method nsed 

 necessitated an alcohol wash and a crystallization 

 from alcohol. This method had to be abandoned 

 owing to excessive cost and another method de- 

 veloped. This method used "Cerelose" as a raw 

 material and ' ' Eponite " as a decolorizing agent. 

 This method had to be abandoned to allow an 

 increase in capacity. Boneblack is now used for 

 decolorizing and the raw material is "Eefined 

 Cerelose ' ' made by the Porst and Newkirk 

 method. Difficulties encountered and methods of 

 overcoming them are described. 



The purification and concentration of enzyme 

 solutions for the rapid analysis of sugars by 

 enzymatic hydrolysis: F. W. Beynolds. Prep- 

 arations of the enzymes invertase and melibiase 

 were purified by dialysis followed by treatment 

 with a very small proportion of acetic acid, which 

 caused flocoulation of impurities. Substances 

 which stabilize the impurities flocculated by acetic 

 acid are apparently removed by dialysis. This 

 treatment is fully as efficient as clarification with 

 neutral lead acetate and does not cause loss of 

 enzymic activity. The filtrate may then be con- 

 centrated to practically any desired extent bj' 

 ultra-filtration, using collodion filters of special 

 composition. Highly active and brilliantly clear 

 solutions of invertase and melibiase of great sta- 

 bility were thus obtained. This method of puri- 

 fication and concentration permits the use of these 

 enzymes as analytical reagents, for rapid analysis 

 of sucrose and rafiinose. The construction of a 

 suitable ultra-filter from materials generally 

 available is described. 



The estimation of rafjinose and sucrose in beet 

 products: E. P. Jackson. A modification of 

 the enzyme method permits an accurate determina- 

 tion of true rafiinose without the difficulty of 

 measuring small changes in polarization in the 

 presence of large amounts of invert sugar. After 

 sterilization of the molasses, the greater part of 

 the invert sugar is removed by fermentation with 

 bakers' yeast. The solution containing the meli- 

 biose is filtered, evaporated and divided into two 

 aliquots, which are diluted one tenth, one with 

 water, the other with the invertase-melibiase solu- 

 tion extracted from brewers ' yeast. After hy- 

 drolysis, both are analyzed for reducing sugar. 

 The diff^erenee between them is a measure of 

 rafiinose. The method is not standardized against 



pure rafiinose. By the above method analyses 

 were made of samples of Colorado beet molasses. 

 True rafiinose was found to be sometimes less 

 and sometimes greater than that indicated by 

 Clerget. Prom the true rafiinose and true sucrose, 

 the direct polarization of the sugars was com- 

 puted. The difference between the calculated and 

 observed direct polarizations give the rotation of 

 the non-sugars. In every case these proved to. be 

 negatively rotating. 



A simple diffusion battery for laboratory and 

 lecture room experiments : M. J. PRorriTT. Each 

 cell of the battery consists of a friction top tin 

 can to the inner walls of which near the bottom 

 is soldered a circular woven wire screen molded 

 to a concave shape. A suitably bent copper tube 

 is soldered with a perforation in the side of the 

 can below the screen, and it extends on the outside 

 above the top of the can, to connect with the juice 

 line. It may be provided with a steam jacket for 

 a colorisator. Two short copper tubes are soldered 

 into perforations in the Ud of the can, one for an 

 air-vent and the other for connecting to the 

 water-line. The juice, water and cross-over lines 

 consist of glass T-tubes with rubber connections 

 and pinch-cocks. A 14-cell battery without 

 colorisators requires 14 friction top cans, enough 

 v.irc screen to make the screens, depending upon 

 the size of the cans used, about 60 pinch-cocks, 

 60 glass T-tubes, 20 feet of copper tubing, some 

 solder, and 50 feet of thin-walled rubber tubing. 

 At current prices, it will cost about $30 and 

 require one day's time to set up. It serves for 

 experiments on water extractions and for familiar- 

 izing students with the actual operation of the 

 difi'usion process as carried out in the manufac- 

 ture of beet sugar. 



Frecipitation of gum from beet molasses: H. S. 

 Paine and C. P. Walton, Jr. In order to permit 

 a study of the properties of the gums present in 

 beet molasses, and the effect of such gums on the 

 analytical control and certain phases of the fac- 

 tory process, the following method of preparation 

 was evolved. It is considered more rapid than 

 the dialysis method previously described. Each 

 kilogram of molasses is diluted with 10 liters of 

 water, and to this solution are added 1.4 liters of 

 ammoniacal lead acetate and 0.4 liter of strong- 

 ammonium hydroxide. After filtration of the 

 precipitate, it is suspended in water and decom- 

 posed with 1:4 H^SO in carefully regulated 

 amount. The filtrate is neutralized with solid 

 barium hydroxide in the cold, concentrated in 

 vacuo and dialyzed against running tap water. 



