1108 EXPKHIMENT STATION HECORD. 



On milk judging. II. 11. C'hristenskn {Tidsskr. Landiikonomi, HIGH, Noh. 11, 

 pp. 555-'>li0 ; IS, pp. (!!>0-(!!)2). — This paper contains a discussion of the reductase 

 test as to the purity and lieopinj; (piality of niillc, originally proposed by Neisser 

 and WechslxM-^. Tlie results obtained by Bartlicl ( K. S! R., 20, p. 12) are 

 qnoted at len.^th. 



A new reaction differentiating raw milk from heated (pasteurized) milk, 

 as well as for the detection of hydrogen peroxid, W. I*. Wilkinson and It. C. 

 I'KTKRS (Join: Dcpt. Afjr. Victoria, G (JHOS), Xo. .',, pp. 251-253; Ztschi: Untcr- 

 .-iitrfi. Xolir. II. (Icniissintl., Hi (1908), No. 3, pp. 172-nJi; ab-t. in Rev. Clin. Lait, 

 7 ( WOS), \o. 7, p. U)2). — This is a critical review of the methods which have 

 been susflfsted for this purpose. 



The authors also jjive the results of their experiments with I)enzidin according 

 to the following method: "To 10 cc. of the millc to be tested are added 2 cc. 

 of an alcoholic solution of l)enzidin. then 2 to .'i drops of glacial acetic acid (just 

 sullicient to cause coagulation of the milk), shake the whole, and finally add 

 2 cc. of a 3 per cent solution of hydrogen peroxid. If the milk is unboiled or 

 if it has not been heated to above 78° C, an intense blue coloration is immedi- 

 ately produced. Milk which has been heated to above 80° does not show any 

 change by this treatment." 



The advantages of using the benzidin test are that the reaction is more relia- 

 ble than either the guaiac or potassium-iodid test, and more sensitive and 

 intense than the iiaraphenylendiamin test. The reagent is also cheaj) :iud will 

 keep for a long time. "The usefulness of benzidin as a test for imboiled milk 

 may be extended by reversing the reaction and applying it as a very sensitive 

 test for hydrogen peroxid." 



The freezing point of milk as affected by the addition of water, P. Fischer 

 (Pharm. Ztg.. 53 (1908), No. 5, pp. ^8, 49).— The author found the freezing 

 point of 100 samples of milk to vary from — 0..54 to — 0..")S° C Whenever 

 water was added the freezing point was raised, and he concludes that the 

 freezing point of milk will vary according to the percentage of water added to it. 



The freezing point of milk, W. li. G. Atkins (Clicm. Xcir-s, 97 (1908), No, 

 2530, pp. 2J,1, 21,2; Dairy, 20 (1908), No. 237, p. 238; abs. in Analyst, 33 (1908), 

 No. 388, p. 279). — The author found the mean freezing point of milk to be 

 — 0.55° C. and fairly constant, the variations rarely exceeding 0.03°. If milk 

 is skimmed the specific gravity will be too high, but the freezing point will be 

 unaffectetl, as fats have no effect on the freezing point. If water is added to 

 bring the specific gravity to the correct value, the freezing point will be nearer 

 that of pure water. 



A contrivance for the determination of fat in milk by the Gottlieb-Rose 

 method, E. IiIeteb (Hcliicciz. Wctnischr. Chcm. ii. I'hiirin.. .'/ 'i [liXHi), .Yo. 12. 

 pp. 170-172, fig. 1; Ann. CJiim. Analyt., 14 (1909), No. 2. pp. 5-'i-57, fig. /).— This 

 is a description of a tube used in the author's modification of the Gottlieb-Rose 

 method of determining the fat content. 



The determination of fat in skim milk, R. Leze (Ann. Chim. Analyt., 13 

 (1908). No. 5. pp. 179. 180; abs. in Ztfichr. Untrr.such. Nahr. u. GcnussmtL, 16 

 (1908). No. 11, p. 701). — The author adds ammonia and sodium hydroxid to 

 skim milk, which is then centrifuged and the portion containing the fat tested 

 as in the case of whole milk. 



A study of the Leze process for the analysis of skim milk, R. Leze, 

 Routines, and Duflos (Rev. G6n. Lait, 7 (1909), No. 9, pp. 193-W7).—In order 

 .o overcome the variable results obtained in some cases by the LezC' method, 

 noted above, the authors point out the conditions requisite for accurate determi- 

 nations with this method. 



