1920] AGRICULTURAL CHEMISTRY — AGROTECHNY. 503 



It is extremely proliable that acetic and butyric acids are not tlie only acids 

 present. The type of infection most frequently observed in the fermentinfj mash 

 produces lactic acid. When the mash is infected in this way, the amount of 

 volatile acid accounted for by the Duclaux estimation is lower than in the case 

 of a normal fermentation. 



" When acetic acid is added to the fermenting mash, an increased yield of 

 acetone is obtained, the yield of ?)-butyl alcohol being unchanged. Propionic, 

 and butyric acids when added appear to be converted into the corresponding 

 alcohols. An increased yield of acetone has been obtained by the addition of 

 aceto-acetic ester." 



The properties of a specially prepared enzymic extract, polyzime, com- 

 paring its starcli liquefying power with malt diastase, J. Takamink, jr. 

 and K. Oshima (Jour. Amcr. Chem. .S'oc, .'/2 (1020), 2\^o. 6, pp. 1261-1265).— 

 A comparison of the properties of polyzime, a commercial enzymic extract of 

 AspcrffiUus on/zce, with those of standard malt is reported, together with a 

 chemical analysis of polyzime. The amyloclastic power was determined by 

 the Wohlgenuith method (E. S. R., 20, p. 208) and the saccharogenic power 

 by the Lintner method. 



The o|)tinnim temperature of starch liquefaction by both polyzime and malt 

 extract was ">° C. for a digestion period of from 30 minutes to 2 hours and 

 -10° for 24 hour-s. The optimum reaction of the solution in both cases was 

 neutral or faintly acid. 



The amyloc'astic power of polyzime proved to be from three to five times 

 as great as that of malt extract, while the saccharogenic power was consider- 

 ably less. The diastatic power of polyzime showed no decrease at tempera- 

 tures below -10° but a progressive increase with increasing temperatures 

 above 40°. 



An improved comparator, L. H. Cooi.kdge (Jour. Indus, and Engin. Chem., 

 1.2 ilfl20), No. 5, pp. 400, 500, figs. 2). — This is a modification of the comparator 

 of Hurwitz, Meyer, and Ostenberg.^ 



Two sliding test-tube racks each containing six tubes are so arranged in the 

 comparator that the one carrying the standard tubes can be slid back and 

 forth until a tube is found that compares in color with the first unknown in 

 the second rack. The second rack is then moved along one place and the read- 

 ing of the second unknown found in the same way. The readings may be 

 made by using light directly transmitted, or the comparator may be tlltetl so 

 that light is reflected from a white surface through the tubes. 



This modified apparatus is said to make it possible to compare in a short 

 time a large number of unknowns with the standard tubes. 



The combination of fractionation with si>ectrophotometry in proximate 

 organic analysis, W. K. Matiiewsox {.Jour. Anirr. Chcni. Soc, 1/2 (1020), Xo. 

 6, pp. 1277-121/0).— Tliifi contribution from the Hureau of Chemistry, U. S. De- 

 partment of Agriculture, consists of a brief description of a procedure for the 

 estimation of small amounts of organic compounds by converting them into 

 colored derivatives, separating them from the excess of the reagents and 

 from any other colored substances present by fractionation with immiscible 

 solvents, and finally estimating them by the spectrophotometric method. 



A few experiments illustrating the method are described. 



A method for the determination of bromin, F. WOnsche (Arch. Expt. 

 rath. V. Pharmnhol., 8.} (,1019), Xo. 6, pp. 32H-S.3S. fig. i).— The method de- 

 pcribe<l, which is said to be applicable to the determination of small amoimts 

 of bromin in organic substances, consists in oxidizing the substance first with 



» Johns Uopkins Hosp., Bui. 27(1916), p. IG. 



