745 



ai]d the alkalinity of cows' milk are the greater. Casein forms three 

 comi»onn(ls with calcium or sodium, the mono, di, and tricalcic (or sodic) 

 casein. These are all alkaline to lacmoid and neutral to phenol phtha- 

 lein, and are decomposed by water. If to a sokition of casein in lime- 

 water suHicient hydrochloric or suli)huric acid be added to combine with 

 all the lime ]>icseut,the casein will be completely i)recipitated. If phos- 

 ]>horic acid be used instead the precipitation of the casein occurs first 

 when all the lime has been changed to monocalcic phosphate. Only the 

 dicalcium or disodium casein comi)ounds are curdled by rennet in the 

 presence of water-soluble lime salts, ami the completeness of the curd- 

 ling depends on the amount of lime salts present. The reaction of these 

 casein solutions before the rennet is added is like that of milk, alkaline 

 to lacmoid and acid to phenol phthalein. The acidity of the two is about 

 the same, but the milk is stronger in its alkaline reaction owing to larger 

 amounts of insolultle ]>hosi)hates, and especially to the soluble dialkali 

 phosphate it contains. The less complete curdling of human milk, as 

 compared with cows' milk, is due to the increased alkalinity of the latter. 

 The decrease of milk in acidity when diluted with water is a result of 

 the decomposition of the lime-casein compounds and the phosphates; 

 the diminution of alkalinity is caused only by the presence of lime- 

 casein com])ounds. By cooking, the alkalinity and the acidity of milk 

 are both reduced. The addition of calcium chloride to milk causes no 

 change in its alkalinity but increases its acidity. The change in the 

 casein caut ed by adding rennet to milk has no connection with the reac- 

 tion. In curdling with rennet the dicalcium-casein compound is precip- 

 itated. 



Linseed cake vs. sesame cake for milch cows {Wekelijsche 

 Lamlbotiic Kroniel., 1S92 ; aha. Brannscliwg. landic. Ztg., 1892, p. 31). — 

 In Holland linseed cake was formerly almost universally accredited 

 the first place among concentrated feeding stuffs for milch cows. More 

 recently sesame cake has competed strongly with it, and the past year 

 the Dutch Agricultural Society {Rollandsche MaatscJiappy van Land- 

 home) appointed a commission to test the relative merits of the two 

 feeds in comparative experiments with milch cows. These experiments 

 were made on four different farms, four cows being used in each case. 

 These were divided into two lots, containing animals as nearly alike as 

 possible, one lot receiving linseed cake and the other sesame cake in 

 the first period (March 5 to 26), and both lots being reversed in the sec- 

 ond period (March 26 to April 25). The cows all received the same 

 amount of the basal ration, and like money values of the cakes were fed. 

 The linseed cake cost $4.33 per 100 cakes and the sesame cake $4 

 per 100. 



