I 



1917] AGRICULTURAL CHEMISTRY AGROTECHNY. 415 



it is desired to separate the ammonia from the amins and otlier bases the pre- 

 cipitation of ammonia as ammonium-matrnesium phosphate is recommended. 



The procedures which are applicable to fermented and unfermented fruit 

 wines and juices, together with analytical data relative to the effect of other 

 substances present on the determination of ammonia, are described in detail. 



The amount of ammonia in wines was found to vary from nothing to 150 mg. 

 per liter. The French limit of 20 mg. per liter for maximum content is con- 

 sidered to be unsatisfactory. Fruit wines appear to be very poor in ammonia. 



The significance of the determination of ammonia for both practical and 

 scientific purposes is indicated. 



The determination of ammonia in wine, W. J. Baragiola and O. Schuppli 

 (Ztschr. JJntersuch. NaJir. u. GeniissmtL, 32 {1916), No. 10, pp. .^^i-^^^).— Sup- 

 plementary to the study noted above the distillation with magnesium oxid is 

 again strongly recommended. The use of the precipitation procedure is advised 

 only in cases where it is desired to determine small amounts of volatile amins 

 and other bases that might be present. 



The precipitation of ammonia was found not to be complete except in an 

 excess of sodium phosphate. The use of 12 gm. of sodium phosphate rather 

 than 5 gm. as in the previous procedure is recommended. 



A method for the exam.ination of methyl salicylate, A. R. Albbight {Jour. 

 Ainer. Chem. Soc, 39 {1917), No. 4, pp. 820-82.5).— A method for examining a 

 methyl salicylate ail and other phenolic substances or impurities present which 

 depends on the conversion of the substances into the same crystalline deriva- 

 tive (the benzoate) and the microscopical examination of the resulting crystals 

 is described and discussed. 



A study of certain ferments with, a view to determining- a method for the 

 differentiation of pasteurized milk from raw milk. — I, Reductases, R. E. 

 Lee and M. G. Mellon {Jour. Indus, and Engin. Chem., 9 {1917), No. 4, pp. 

 360-367, figs. 7). — From the study reported the authors conclude that methy- 

 lene blue, as it occurs in Schardinger's F. M. reagent (5 cc. of a saturated 

 alcoholic solution of methylene blue, 5 cc. of 40 per cent formaldehyde, and 

 190 cc. of water), is not decolorized by normal milk in less than 20 minutes. 

 In cases of decolorization effected in 10 minutes or less the milk was found 

 to contain 1,000,000 or more microorganisms per cubic centimeter. Milk pas- 

 teurized at 70° C. for 10 minutes, unless allowed to stand for 48 hours before 

 testing (or until the bacterial content was largely inci'eased), or old milk in 

 which the preservative (formaldehyde) inhibited the growth of bacteria, also 

 did not decolorize methylene blue. The reagent was ordinarily decolorized by 

 normal milk which had stood imder ordinary temperature conditions for from 

 24 to 48 hours. Pasteurization increased the time required for the decoloriza- 

 tion of the reagent. 



In general, no ratio was found to exist between the time required for de- 

 colorization and the number of bacteria in the milk. A general relation, how- 

 ever, appeared to exist between these two factors up to a given point of acidity. 

 Because of a lack of parallelism between these two factors it is indicated that 

 " reductase is of bacterial origin but that not all bacteria found in milk pro- 

 duce this enzym. ... It seems probable that formaldehyde either gradu- 

 ally retards the action of the reductase or destroys it. This is a matter, how- 

 ever, for more careful investigation in the future." 



The experimental data are submitted in tabular and graphical form. 



Characteristic milk powder forms, C. Griebel {Ztschr. JJntersuch. Nahr. v. 

 Oenussmtl., 32 {1916), No. 10, pp. JiJi5-U7, figs. 2).— Some notes on the differ- 



