AGEICULTUEAL CHEMISTRY — AGROTECHNY. 503 



served are said to show no appreciable increase in acidity, and tlie mercuric 

 chlorid had no noticeable effect on the milk constituents. Other substances 

 tested in this regard were chloroform, thymol, oil of mustard, phenol, creosote, 

 sodium fluorid, and potassium bichromate. 



Investigations upon the changes which take place in milk preserved with 

 potassium bichromate, A. Kling, Gelin, and Lassieur (Ann. Falsif., 7 {1914), 

 No. 67, pp. 2JtJt-250). — Potassium bichromate is a convenient, although not an 

 ideal, pi'eservative of milk. If 1 gm. is added to 1 liter of fresh milk the sample 

 is fit for examination for a period of 2 months, and milk preserved with 3 gm. 

 per liter will keep fresh for 3 months. In this study phenol as advocated by 

 Deniges (E. S. R., 30, p. 14) was also used for comparison. Milk preserved 

 with bichromate of potash and kept at 27° 0. coagulated much quicker than milk 

 which was stored at from 18 to 20°. 



The action of milk mold on phenylaminoacetic acid, H. Horsters (Biochem. 

 Ztschr., 59 (1914), No. 5-6, pp. 444-4^0). — Oidiutn lactis when grown on a solu- 

 tion containing phenylaminoacetic acid, monopotassium phosphate, magnesium 

 sulphate, traces of sodium chlorid, ferric chlorid, and either dextrose or invert 

 sugar elaborated benzyl alcohol, very small traces of phenylglyoxylic acid, 

 benzoic acid, traces of formic acid, and i-mandelic acid. 



Volumetric estimation of casein in milk by the aid of tetraserum, B. Pfyl 

 and R. Turnau (Arb. K. Gsndhtsamt., ^7 (1914), No. 3, pp. 347-361).— As a 

 preliminary casein was prepared from cows' milk and its nitrogen and acid 

 equivalents were determined. The average nitrogen content was 15.5 per cent, 

 which corresponds to a factor of 6.45 per cent. For neutralizing 1 gm. of 

 casein toward phenolphthalein 8.75 cc. of decinormal alkali was necessary on 

 the average, indicating an acid equivalent of 1,143. The method for determin- 

 ing casein was as follows : 



To 50 cc. of the milk under examination, cooled to 15° C, add from 5 to 6 

 drops of a 1 per cent phenolphthalein solution and titrate to a pink color with 

 decinormal (carbonate free) alkali solution. Treat another 50 cc. of milk in 

 a stoppered bottle with about 5 cc. of carbon tetrachlorid, shake thoroughly, 

 treat with exactly 1 cc. of a 20 per cent acetic acid solution (of known titer), 

 then shake again, and filter. Then titrate 25 cc. of the serum, after adding 

 from 2 to 3 drops of a 1 per cent phenolphthalein solution, with decinormal 

 alkali solution until a pink tint appears. From the first titration and the titer 

 of the 20 per cent acetic acid solution the alkali required for 25 cc. of milk-f 0.5 

 cc. of acetic acid (a=amount of alkali solution) is determined. From this 

 result, the alkali required for titrating the serum (&==cc. of decinormal alkali 

 solution), and the fat content of the milk (/=gm. of fat in 100 cc. of milk) 

 the casein content is calculated : 



gr=the casein in 100 cc. of milk=0.457 f a-b ^9.3— / \ 



The derivation or the formula is discussed and some results obtained with 

 the method are included. With heated milk the procedure gave correct results. 

 This was not the case with either the Schlossmann or Hoppe-Seyler methods. 

 See also previous notes by Hart (E. S. R., 19. p. 707; 21, p. 613). 



Old and new methods for determining- fat in milk, A. V. Oven (Milchw. 

 Zentm., 43 (1914), Nos. 11, pp. 285-295; 13, pp. 350-356).— A review of the 

 literature, especially with reference to the methods in use in Europe. 



Determination of lactose in milk by the polarimetric method, E. Feder 

 (Ztschr. Untersuch. Nahr. u. Genussmtl., 28 (1914), No. 1, pp. 20-29; ahs. in 

 Ztschr. Angew. Chem., 27 (1914), No. 72-73, Referatenteil, p. 533).— To 75 cc. 

 of milk add 6 cc. of asaprol solution (consisting of 75 gm. of asapi'ol and 75 gm. 



