AGRICULTURAL CHEMISTRY — AGROTECHiSrY. 715 



The chemical processes involved in the fermentation of koumiss and 

 kefir. — II, Artificial koumiss and kefir, A. Ginzberg (Biochem. Ztschr., 30 

 {1910), No. 1-2, pp. 25-38, pi. 1, dgm. 1). — The koumiss utilized in this work 

 was prepared with beer yeast for the production of the alcohol and GrigorofC's 

 Bacillus bulgaricus for the production of lactic acid, etc., and with mares' and 

 cows' milk. The kefir was prepared with kefir grains. 



The work shows that the various processes in the kefir fermentation proceed 

 much slower and less intensely than the koumiss fermentation, and that only 1 

 per cent of alcohol is produced and one-half of the quantity of the lactose is 

 decomposed. With koumiss the alcohol content rises as high as from 2 to 3 

 per cent. 



The author points out the advantage of establishing purely chemical limits 

 which are based on the intensity of the fermentation process, and to eliminate 

 such terms as weak (young and old), medium (young and old), and strong 

 (young and old). 



A number of practiciil hints on the preparation of koumiss and kefir are also 

 given. 



The determination of camphor, H. C. Fulleb (U. .S. Dept. Agr., Bur. Vhem. 

 Circ'. 11, p. 1 ) . — As camphor is extensively used in medicine, and the United 

 States Pharmacopoeia contains preparations which must legally contain definite 

 amounts of camphor, the author has elaborated a procedure for determining 

 this substance. It is based on the fact that camphor forms with hydroxylamin 

 a well defined oxim (CioH,uNOH). 



Quantitative estimation of nitric acid in veg'etable products, K. Keog 

 and J. Skbelien {Chvin. Ztg., 3'> (19/1), Xo. 11. pp. I ',■',. I ',r, ; nhn. in Annhj-^t, 36 

 (1911), No. Ji21, pp. 163, 16.'t). — According to the authors Tiemann's modification 

 of Schloesing's method, when used for determining niti-ic acid in vegetable 

 products which contain much sugar (beets), yields inaccurate results owing to 

 the reducing infiuence of the carbohydrates. While it is possible to remove the 

 saccharose by precipitation as barium sucrate, the invert sugar which accom- 

 panies it can not be removed in this way. 



In this connection the authors tested the value of Busch's nitron method 

 (E. S. R., 16, p. 945) with aqueous and alcoholic extracts. The method gave 

 with an alcoholic extract 1.65, and with the aqueous extract 1.63 per cent. 

 Schloesing's and Tiemann's methods, on the other hand, yielded only 1.38 per 

 cent. The authors have introduced certain modifications into the Busch method. 



Determination of malic acid, P. B. Dunbar and R. F. Bacon (U. S. Dept. 

 Agr., Bur. C'hcm. Circ. 16, pp. 12). — A neutralized solution of malic acid when 

 treated with uranyl acetate shows an increase in rotation which corresponds to 

 approximately 28° Yentzke for each per cent of malic acid present in the solu- 

 tion. This principle is recommended by the authors for estimating malic acid 

 quantitatively in substances free from d-tartaric acid, which is affected in the 

 same way, by ti*eating its solution with uranyl acetate, polarizing, and multi- 

 plying the difference obtained between this reading and a reading made of an 

 untreated portion of the solution by 0.036. This x'epreseuts the amount of 

 malic acid present. 



The most favorable limits of concentration for the method were found to He 

 between 0.2 and 2.5 iier cent, and the percentage of error was never found to 

 exceed '5 per cent of the malic acid present. The method, according to the 

 authors, differs materially from the one previously noted (B. S. R., 24, p. 612), 

 and with it 12 determinations can be made with ease in a few hours' time. If, 

 however, more than 10 per cent of reducing sugars and less than 0.25 per cent 



