AGRICULTURAL. CHEMISTRY — AGROTECHNY. 13 



by pepsin-liydrochlorie acid than casein. Tlie casein and paracasein from goat's 

 millv reacted in tlie same manner as those ft-om cow's milk. 



Boiling- test, alcohol test, and acidity degree of milk, O. Rammstedt 

 (Ztschr. Offcntl. Chcm., 17 (1911), Nos. 23, pp. Ul-J,55; 2J,, pp. 467-471; abs. in 

 Ztschr. Angew. Chcm., 25' (1012), No. .9, p. 436). — No definite relation exists 

 between the alcohol coagulation and the acidity of milk, but, on the other hand, 

 the boiling, alcohol, and acid tests are of value as preliminary tests for milk 

 hj'gienic work. Milk obtained under cleanly conditions has better keeping 

 qualities than either pasteurized or raw market milks. The rennet, fermenta- 

 tion, catalase, reductase, and leucocyte tests are valuable in detecting impure 

 milks. 



The guaiac test for distinguishing between raw and boiled milk, K. 

 ScHKRN and W. Schellhase (Berlin. Ticrarztl. WcJinschr., 27 (1911), No. 48, 

 pp. SG8, 869). — As all guaiac tinctures do not serve as reagents for distinguish- 

 ing raw milk from boiled, the author proposes a formula for preparing a 

 reagent which will give a positive intense blue coloration when raw milk is 

 present. This formula consists of resin, guajaci 10 gm., guajacoli 10 gm., per- 

 hydrol (3 per cent) 1 drop, and absolute alcohol SO gm. This is termed the 

 guaiac-guaiacol test. The use of the test in foot-and-mouth disease and tuber- 

 culosis is also considered. 



Is the blue coloration obtained with tincture of guaiac an accurate indi- 

 cation that milk has not been boiled? H. Tewes (Molk. Ztg. [Ilildesheim], 

 25 (1911), No. 79, pp. 1499, 1500). — If a brown color is obtained with the guaiac 

 test, the milk in all probability has been boiled. If, on the contrary, a violet 

 or bhie coloration is obtained it is necessary first to determine whether s<:)me 

 oxidizing agent or water has not been added to the milk. Boiled milk sub- 

 sequently contaminateil with bacteria or mill dust will al.so give a positive 

 reaction. 



The Schardinger reaction for milk, W. Rullmann (liiocheni. Zt.schr., S2 

 (1911), No. 5-6, pp. 44^-472). — Milk containing micro-organisms and thermost- 

 able bodies and milk free from them decolorize together or alone Schardinger's 

 methylene blue-formalin solution in a few minutes at temperatures varying 

 from 45 to 50° C The formaldehyde in the reagent may be replaced by an 

 equivalent amount of formic acid, but the appearance of the reaction requires a 

 much longer time. The reaction in sterilized milk with either methylene blue- 

 formaldehyde solution, or methylene blue-formic acid solution is probably due 

 to the presence of thermostable bodies. The age of the milk has no influence 

 upon the reaction, providing of course that the milk remains sterile. If small 

 amounts of sodium hydroxid, ammonium salts, and phosphates are added the 

 reaction is accelerated, particularly if a little milk sugar is added at the same 

 time. Milk sugar when added alone is inert. Increasing the temperature some- 

 what will also aid the accelei'ation of the reaction. 



Raw, pasteurized, and sterilized milk, and milk which has been boiled for a 

 certain time were found to behave diffei'ently as regards the time required for 

 the decoloration of the reagent. This is probably due to the demineralization 

 of the milk, which begins at 4-50°, the destruction of the enzym, which starts 

 in at 65 to 69°, and the . decomposition of the proteins, which is influenced by 

 heat. 



Contrary to Sames and Romer's findings (E. S. R., 23, p. 709; 24, p. 412), 

 the author never noted the absence of a positive reaction with milks which 

 were retained in the udder longer than usual, or was there ever any absence of 

 the reaction in the initial milk. 



The Rothenfusser reaction was found to be very accurate, and to' detect an 

 addition of 1 part of raw milk to 1.000 parts of boiled milk. The Schardinger 



