AGRICULTURAL CHEMISTRY AGROTECHNY. 211 



should furnish both a delicate and reliable guide to the detection of added water 

 in milk. As both the methods may be used on the same serum, and as the de- 

 terminations are easily made after the serum has been obtained, it appears 

 that a combination of the two methods would insure the certain detection of 

 added water, if in any quantity as would be used in fraudulently adulterated 

 milk." 



Cryoscopic examination of milk, L. Stoecklin (Ann. Falsi/., 4 {1011), No. 

 81, pp. 232-257, figs. 8; abs. in Analyst, 36 (1911), No. 42^, pp. 3^5, S^G).— As a 

 result of examining 2,500 samples of milk covering a period of 4 years the au- 

 thor concludes that with the cryoscopic method one can distinguish between a 

 watered and an unwatei'ed milk without taking into consideration the age of 

 the animal or the period of lactation. It was also found that where the lactic 

 acid content of the milk increases to 1 gm. per liter the freezing point increases 

 from about 0.045 to 0.05° C. Potassium bichromate (1 gm.) increases the 

 acidity equivalent to 0.614 gm. of lactic acid. The amount of bichromate that 

 will influence the freezing point of a milk containing it is found according to 

 the formula L=A — (1.20+CrX0.061), where L equals the real lactic acid pres- 

 ent in a liter of milk, A equals the total acidity expressed as lactic acid, and 

 Ci the weight in grams of potassium bichromate in a liter of milk. Where a 

 milk contains an addition of 10 per cent of water the nonlactic acidity is re- 

 duced from 1.2 to 1.08, and for a milk which contains 20 per cent of water to 

 0.96. One gm. of potassium bichromate was found to increase the freezing 

 point of a milk by 0.018° C. 



The behavior of the Schardinger reaction in colostral milk from cows, 

 R. Reinhabdt and E. Seibold (Biochem. Ztschr., 31 (1911), No. 3-ff, pp. 294- 

 320). — The cows used in these tests were animals quartered in the obstetric 

 clinic of the Royal Veterinary High School at Stuttgart. Some of the milks 

 examined were obtained under ordinary conditions and others under sterile 

 conditions. 



It was noted that almost invariably after the birth of the calf and some days 

 thereafter the milk (colostrum) yielded the Schardinger reaction. With fresh- 

 milking cows, as defined by Schern (E. S. R., 21, p. 614) the reaction did not 

 occur, and only reappeared from about 3 to 8 weeks post partum. Suckling 

 did not have any influence upon the return of the Schardinger reaction. Gen- 

 eral diseases and udder inflammations had an influence upon the reaction, but 

 sterile milk gave the same reaction as milk obtained under ordinary conditions. 

 The enzym (reductase) was not found to have any relation to the amount of 

 fat in the milk, but the amount of enzym was found to be greatest in the cream 

 and the residual milk. On the other hand, the enzym was never totally absent, 

 not even in the milk of fresh-milking cows, because in all cases traces of the 

 enzym could be noted in the cream and residual milk. No antireductase was 

 observed. The relation between the enzym content of freshly lactating cows 

 and cows in the late stages of lactation was found to be only a qualitative one. 

 Ten cc. of the milk from old lactating cows was usually found to decolorize 1 cc. 

 of the Schardinger reagent within from 4 to 12 minutes, but the time between 

 the milkings had some influence upon the appearance of the reaction. 



Fractionated milking tests showed that the middle and residual milks had 

 the highest enzymatic activity, while the initial milks showed the least. The 

 individual quarters were found to yield Aarious amounts of enzym. The enzym 

 is destroyed at temperatures beginning at 65° C, but the optimum temperature 

 for milks from late stages of lactation was found to be 65° C. and for freah- 

 milking cows it was 45° C. 



The authors expressed the opinion that the enzym, if such exists in the milk, 

 is present in a preformed state. 



