AGEICULTUEAL CHEMISTEY — AGROTECHNY. 413 



Practicum of milk chemistry, O. von Soube {MUchchemisches Praktikum. 

 Lcipsic, 1913, pp. V-\-162). — This book is designed for self-instruction and for 

 dairy laboratories, in place of the author's previous work called the A B C 

 des Molkereibeamten (A B C of the Dairy Official). In addition to the usual 

 nietbods for examining dairy products the chemicr! iiud biologic methods em- 

 ployed on the Euroi)ean Continent are described with much detnil. 



A new method for the determination of the proteins i,i milk, W. C. de 

 Graaff and Mlle. A. Schaap (Ann. Falsif., G {1913), No. 53, pp. 149-157).— 

 This is a study and criticism of Steinegger's method. 



It was found that with unboiled cow's milk the factor for 1 gm. of protein 

 obtained by the authors agreed well with the figure found by Steinegger, 2.06 

 (E. S. R., 17, p. 696), but not with that noted by Richmond, 2.23 (E. S. R., 22, 

 39). Steinegger's claim that no change of the aldehyde index after heating the 

 milk to 120° C. takes place could not be borne out because the figures obtained 

 by these workers were very variable. Ordinary pasteurization or sterilization 

 evidently produces some changes in the protein substances. Dilution did not 

 alter the aldehyde index. 



Six samples of women's milk were also studied in this regard, and the 

 aldehyde index for 1 gnj. of woman's milk j)roteiu was found to be 2.26. The 

 aldehyde index for 1 gm. of the protein of buttermilk was 3.15. The difi'erence 

 in value between the normal proteins and the proteins of buttermilk is not 

 believed to be due to the development of lactic acid but probably to cleavage 

 of protein taking place under the influence of the micro-organisms present. 



The addition of lactic acid did not affect the results. See also other notes 

 (E. S. R.. IS. p. S; 27, p. 209). 



A simple method for determining the fermenting capacity of various 

 feeding stuffs, milk, and the galactase of milk, A. Rosam {Milchiv. Zentbl., 

 42 (1913), No. 7, pp. 193-195, flgs. 2).— Infant foods and feeds for animals 

 often contain micro-organisms which gain entrance to the gastrointestinal 

 tract where they exert a detrimental effect. For determining the fitness of 

 such foods, a method is proposed which is said to be a modification of the 

 author's prior procedure. 



The apparatus consists of a tall, tapered, flat-bottomed flask supplied with 

 a rubber cork through which a glass tube passes. The tube dips into the flask 

 5 cm. below the cork while the outside portion of the tube is from 30 to 50 

 cm. above the cork. If a food is to be examined, a definite portion is mixed 

 with water and the apparatus with its contents is attempered at 35 to 40° C. 

 The height to which the fermenting mixture rises in the glass tube at the 

 end of three hours is compared with the standard set down. As a basis for the 

 test a rise of 30 cm. in three hours is taken. This fermentation is designated 

 ^=10=100 per cent. 



If the effect of feces or other contaminating substances upon milk is to be 

 studied, sterile milk is substituted for the water. 



Tests made gave the following figures : Feed beets, 43 to 60 per cent ; fresh 

 beet chips, 30 to 50; soured beet chips, 10 to 18; dried chips, 25 to 40; green, 

 dirty cabbage leaves, 40 to 60; bran, 50 to 70; hay, 30 to 45; fresh brewers' 

 grains, 0.5 to 5; unclean straw, 65; feces, 50 to 70; and milk, 4 to 20 per cent. 



As the results obtained with the different materials vary, it is necessary to 

 set up a standard for each kind of material to be tested. The fermenting 

 ]wwer of feces depends very much upon the kind of feed an animal receives. 

 The feces of animals affected with dysentery yield high figures. 



The apparatus described can also be used for catalase determination. 



The determination of nitrobenzol in peanut oil, H. J. Lucas {Jour. Indus, 

 and Engin. Clicm., 5 {1913), No. 7, pp. 576, 577).— Nitrobenzol is usually added 



