714 EXPERIMENT STATION RECORD. 



other hand, it is cheaper, safer, and more portable, and might be safely recom- 

 mended to dairy farmers and others, to replace the acid method where this 

 offers serious disadvantages; but the introduction of another possible error 

 will prevent it from replacing the original Gerber method for more accurate 

 work, though the method is a great advance on the previous alkaline methods." 



Influence of various preservatives upon the results obtained with the 

 "sal" method in the examination of milk and cream, Hesse (Milch Ztg., 

 39 {1910), No. Jf6, pp. S.'i'i, 5fi5). — The results of a comparative study between 

 the "sal" method and the Gerber method with milks preserved with formalde- 

 hyde, potassium bichromate, and copper ammonium sulphate are reported. The 

 Gerber method was found to be influenced to a greater extent by the presence 

 of preservatives in milk aud cream than the " sal " method. 



Determination of fat in butter by the " sal " method, M. Kersten {Molk. 

 Ztg. [Hiklesheim], 2Jt {1910), No. 18, pp. 311-313).— In order to determine the 

 value of this method for butter in the hands of practical men, the author se- 

 lected a number of students, etc., to try it out. The results obtained were com- 

 pared with gravimetric determinations with the same material, and showed 

 that the " sal " method, when conducted according to si>ecifications and taking 

 particular precaution not to shake the mixture, is a good accurate method. 



Recent methods for examining butter for foreign fats, especially veg'etable 

 fats, C. Barthel {Svensk Kern, Ticlskr., 22 {1910), No. 5, pp. 106-110).— A 

 resume of methods, with particular reference to the detection of coconut fat 

 by means of the phytosterin acetate method and the Polenske number. 



Methods of determining ice cream thickeners and household tests for 

 renovated butter and oleomargarine, G. E. Patrick {Amer. Food Jour., 5 

 (1910), No. 8, pp. y,-7).— Previously noted (E. S. R., 13, p. 321 ; 20, p. 168). 



The chemical processes involved in the fermentation of koumiss and 

 kefir. — I, Investigations of koumiss in the Steppes, A. Ginzberg {Biochem. 

 Ztschr., 30 {1910), No. 1-2, pp. 1-2^, dgms. 3). — Inasmuch as there are various 

 processes going on at the same time in the fermentation of koumiss and kefir, 

 the author points out the impossibility of controlling the process by determining 

 only the acidity. When utilizing various titration solutions such as tenth 

 normal barium hydrate, tenth normal potassium hydrate, or a saturated solu- 

 tion of calcium hydrate, a disagreement among the final results was noted. The 

 author, however, recommends diluting the koumiss with an equal amount of 

 milk and then dividing it into 3 portions. Each of the 3 portions is allowed to 

 ferment 6, 24, and 36 hours, respectively, and at the end of the fermentation 

 period the total acidity, alcohol, and sugar are determined. A parallel bio- 

 logical examination is also made. 



The flora most active in the fermentation of Katyk koumiss from mares' 

 milk was found to consist of a long rod which often appeared in chains, simu- 

 lated leptothrix, and an organism belonging to the true saccharomycetes or, 

 possibly, to the torulte. 



The author further points out that the formation of peptones is not directly 

 the result of a biological process, but is simply an ordinary hydrolysis of the 

 proteins by acids. 



As a result of making a parallel study of the decomposition of lactose and 

 the formation of alcohol and lactic acid, it could be noted that at the beginning 

 of the process only a slight production of alcohol took place, but it increased 

 abruptly as soon as the yeast began to multiply and the sugar began to be 

 decomposed. The lactic acid and alcohol formation became intense only when 

 a certain equilibrium was established, and the competition between the yeast 

 fungus and lactic acid bacterium became less. 



The coniiwsition of koumLss and kefir is given and compared. 



