612 EXPEBIMENT STATION RECORD. 



former toward the neutral point. Calcium chlorid, apart from its effect upon 

 [H.], increases the activity of the rennin ferment from the beginning of the 

 digestion process." 



Determination of the degree of homogenization of milk, O. von Sobbe 

 {Milchio. Zenibl., 43 {19lJi), Ko. 20, pp. oOS-oOG ; abs. in Jour. Soc. Cliem. Indus., 

 SIf (1915), No. IJf, p. 813). — "Two hundred and fifty cc. samples of treated and 

 untreated milk are placed in graduated tubes and allowed to stand for 72 hours 

 at room temperature. Each sample is then divided into three layers of 50, 

 150, and .50 cc, respectively, and the fat content of each of these is determined 

 by Gerber's method, except in the case of the lowest layer, or untreated milk, 

 when Kohler's method is preferable. Prior to the analysis, each sample is 

 treated with formalin (1 drop to 100 cc. of milk). The fat content of the 

 lowest layer expressed as a percentage of that of the original milk is termed 

 the decree of homogenization." 



An easy test for bacteria in milk and cream (Barthel's reductase test im- 

 proved), H. JoNE {Brooklyn, N. Y.: Author, 1915, pp. 23, fig. 1). — Tliis publica- 

 tion is designed primarily to meet the needs of milk dealers, creamery em- 

 ployees, condensary employees, etc. Simple and detailed directions for the use 

 of the methylene blue reductase test for the determination of the bacterial 

 activity in milk are given. Directions for the preparation and standardization 

 of an improved methylene blue solution, which must be uniform for accurate 

 results, are also included. 



The deteiTuination of sucrose in condensed milk, G. W. Knight and G. 

 FoRMANEK {.Jour. Indu.H. and Knyin. Chcm., S {1916), No. 1, pp. 28-^/).— After 

 discussing the various methods commonly used, the following procedure has 

 been outlined : 



The can of milk is heated for a .short time in a 100' C. oven, cooled in a 

 desiccator, weighed, and the contents transferred by means of hot water to a 

 500 cc. volumetric flask. The empty can is then dried and weighed and the 

 weight of the milk (W) determined by difference. The contents of the flask 

 are thorougldy shaken until the solution is homogeneous, filled to the mark with 

 water, cooled to room temperature, and shaken. Aliquot portions of 50 and 

 100 cc, measured in volumetric flasks, are transferred by rinsing to 200 cc. 

 volumetric flasks and clarified by the addition of 1.7 cc. of 5 per cent phospho- 

 tungstic acid and then, after shaking, of 2.1 cc. of a 26 per cent neutral acetate 

 solution. 



After being made up to the mark the liquid is filtered and the lead in the 

 filtrate precipitated by the addition of potassium oxalate, a large excess being 

 avoided. The solutions are then filtered, the filtrate being tested for the com- 

 plete precipitation of the lead and portions polarized at 20°, preferably in a 

 Bates instrument. The direct polarization (P) corrected for the volume of 

 precipitate is obtained by multiplying the reading of the dilute solution by 4 

 and subtracting the reading of the stronger solution. Other portions of the milk 

 are treated in a similar manner and inverted by means of concentrated hydro- 

 chloric acid by standing over night at room temperature. The solutions are 

 then neutralized, again slightly acidified with a few drops of tenth-normal 

 hydrochloric acid, and portions polarized the same as before inversion. The 

 polarization (P*) is obtained in the same way as the previous polarization. 

 The following formula is used for calculating the sucrose in the condensed 

 milk : 



T> , , 2G.0O0(P-P') 



Percentage of sucro&e=-^T^ ... __ y,^, 



T=the temperature in degrees at which the invert reading is made. 



