14 EXPERIMENT STATION RECORD. 



Casein, on the other hand, reacts with certain bases as an acid. It was further 

 noted that long before the actual coagulation takes place paracaseins are suc- 

 cessively produced, with always a greater and greater affinity for calcium phos- 

 phate. As a result of this the paracasein takes up more and more calcium 

 phosphate, until tinally so much is in combination with it that coagulation takes 

 place. 



Coagulation, according to the author, is many phased. There are first 

 numerous phases of paracasein formation, and in the others the combination of 

 paracasein and the calcium phosphate takes place, this probably requiring the 

 longest time for its execution. The author does not believe that rennet should 

 be classed among the coagulating enzyms, as the coagulation of the paracasein 

 is in reality brought about by the calcium salts and therefore can not be con- 

 sidered a true coagulation. 



Contribution to our knowledge of milk catalase, F. Spindleb (Biochem. 

 Ztschr., 30 {1911), No. 5, VP- 38Jf-Jil2, fig. i).— This work, which was conducted 

 with Lobeck's apparatus (E. S. R., 23, p. 13), brought out the fact that the 

 highest catalytic power was present in goats', cows', and pigs' colostrum and 

 which is smaller if the sample is taken after milking or feeding the young. 



An abnormal catalase figure (as compared with normal milk) is usually 

 present for 8 days after birth, but if present after that time it is due to an 

 inflammation of the mammary gland. Mastitis milks have a large catalytic 

 power throughout the whole cycle of the disease, and sometimes retain it for 

 considerable time after the disease is no longer apparent. Udder diseases, 

 such as abscess and necrotic areas in the glinuls, cow pox, and udder furuncu- 

 losis also yield a milk with a high catalytic figure. In other diseases, such as 

 peritonitis and tuberculosis (without udder involvement), a large figure may 

 be present during certain stages of the disease. 



Fresh milk rich in catalase is usually alkaline, and in many instances an 

 undiseased gland will yield more than the standard amount of oxygen (2.5 cc. 

 from 15 cc. of milk). Milks which have an addition of sodium bicarbonate, and 

 those obtained from practically dry and sterile animals, also have a high cata- 

 lase content. The author points out the value which the test may have for 

 identifying diseased quarters, but states that the limit of 2.5 cc. is much too 

 low. It was found that goat's milk at times yields very low figures and at other 

 times abnormally large figures for catalase. Yogurt and kefir yield high cata- 

 lase figures, but these are proportionate to the age of the milk product. 



Estimation of catalase in milk, von Heygendorff and Meuber (Milchio. 

 ZentU., 6 (1910), No. 12, pp. 529-533) .—The authors determined the oxidizing 

 capacity (catalytic activity) of various milks with Lobeck's apparatus (E. S. R., 

 23, p. 13) and under varying conditions. In conjunction with this, the bac- 

 terial content of milk was also noted. The results show that the oxidizing 

 capacity rises with an increase in bacterial content, and that where a high 

 catalytic power is present a large bacterial content is to be expected. 



Detection and determination of nitrates in milk by the diphenylamin- 

 sulphuric acid reaction, J. Tillmans (Ztschr. Untersuch. Nahr. u. Genussmtl., 

 20 (1910), No. 11, pp. 676-707; Mollc. Ztg. Berlm, 21 (1911), Nos. 2, pp. 16, 

 17; 3, pp. 26-28). — The reaction has been very thoroughly examined by the 

 author, who finds that the presence of small amounts of chlorids seems to be 

 essential to the development of the coloration obtained with the diphenylamin- 

 sulphuric acid reagent with small and relatively large amounts of nitrates. 

 The reaction is also of value for nitrites, the only difference being that with 

 nitrites the reaction appears quicker, and that chlorids are not necessary. 

 Proteins, particularly peptones, and milk fat prevent the formation of the blue 

 color, but the milk can be freed from all objectionable bodies by treating it 



