682 EXPERIMENT STATION RECORD. 



milking cows. The results of examinHtions of the butter, monthlj^, for a 

 3'ear showed in the case of both new and old milkers that the refractive 

 index of the butter fat and the iodin number increased considerabl}'^ 

 when the cows were let out in the spring, and decreased when the}'' 

 were changed to stable feeding in the fall. 



The changes in the refractive index and iodin num])er during the 

 period of lactation follow each other closelv, decreasing during the first 

 3 months after calving, to increase from that time on until the cows 

 are drv; while the Reichert number changes but little up to the fifth 

 month after calving, from which time on there is a stead}^ decrease 

 till drving-off time. 



The variations in the case of individual cows are tabulated and com- 

 pared with those for creamery butter. The general conclusion is 

 drawn that variations in the chemical properties of Danish export 

 butter are not due to adulteration, as has occasionallv been claimed, 

 but are caused by the natural variations in the butter fat from the 

 individual cows. — f. w. woll. 



On the biology of peptonizing milk bacteria, O. Kalischer 

 {Arch. Ilyg., 37 {1900), No. i, 2)p. 30-5S).~V\\& author's investigations 

 were made with a bacterium belonging to the group of hay or potato 

 bacilli, which, according to Fliigge, are not killed b}' heating milk to 

 90-95°. It possessed the property of curdling milk by means of a rennet- 

 like ferment and then of dissolving the precipitate of casein by means 

 of a peptonizing ferment. The investigations showed that its growth 

 in milk was accompanied by a diminution in the milk sugar, which is 

 believed to be directl}' connected with the life process of the bacteria. 

 The inversion of the sugar took place entirel}' within the cell, and no 

 ferment capable of inverting milk sugar was formed. The only 

 decomposition products of the milk sugar which could be identified 

 with certainty were volatile acids. The fat was not attacked b}- the 

 bacteria, and no diastatic ferment was elaborated. The products of 

 its action on casein were albumose and later peptone, together with 

 ammonia, volatile fatty acids, and a number of other substances. By 

 fermentative action alone there was produced from the casein peptone, 

 leucin, and tyrosin, the aromatic oxy acids, and ammonia in small 

 qnantit}'. Except in its ability to produce oxy acids, the digestive fer- 

 ment corresponded entirely to trj'psin. The rennet ferment produced 

 by the bacteriuni was very analogous to ordinary' rennet. 



Studies on the enzyms of cheese, O. Jensen {Ann. Agr. Suisse^ 



1 {1000), No. 6, 2)p. 150-10,S).—Tho. o])ject was to study the enzyms 

 found in cheese, and the I'ole thi^y play together with bacteria in the 

 ripening processes. Lim burger is taken as a representative of the 

 soft, while Emmenthaler is chosen as a type of the hard cheeses. 



The author finds 2 enzyms active in the ripening processes of the 



2 cheeses, galactase of milk and pepsin of rennet. These cnzvms 



