1917] DAIRY FARMING DAIRYING. 375 



centage content of protein and sugar in sliim milk from different breeds of 

 cows was calculated as follows : Ayrshire, 3.46 and 5.2 ; Holstein, 3.25 and 4.8 ; 

 Guernsey, 4.04 and 5.23; Jersey, 3.99 and 5.30; and Shorthorn, 3.44 and 5.07, 

 respectively. On the basis of analyses of whole milk at the Ohio Station, the 

 skim milk from three Holstein cows was calculated to contain 3.12 per cent 

 protein and 5.06 per cent sugar, and from four Jersey cows 4.26 per cent 

 protein and 5.18 per cent sugar. 



To further test the relation of the fat content of whole milk and the com- 

 position of skim milk obtained therefrom, analyses of 807 samples of 10 groups 

 of milk made at the Ohio and other stations are summarized. These groups 

 ranged in fat content from an average of 2.19 per cent to 7.4 per cent. The 

 percentage of protein in the skim milk was found to undergo a regular and 

 progressive variation, being at its lowest point of 2.67 per cent in the extreme 

 low-testing fat group and increasing regularly as the fat test increased, 

 though not so rapidly. An increase of 5.21 per cent of fat between the average 

 test of the first and last group was accompanied by an increase of only 2.38 

 per cent in the protein content of the skim milk. The sugar content in general 

 varied with the protein content, but the variations were not so regular or 

 marked. It was found that the fat content of mixed milk from several cows 

 or of a composite sample of several milks from one cow does not often show 

 much change without a corresponding variation in the skim milk solids. 



The author concludes that " the fat content of milk as indicated offers a 

 convenient and practical basis for computing with reasonable accuracy the 

 composition of the skim milk derived from it." 



The significance of the act of milking', C. Ckowtheb (Rpt. Brit. Assoc. Adv. 

 Sci., 85 (1915), pp. 779, 780). — Data are reported in support of the hypothesis 

 that in addition to the removing of preformed milk in the udder the operation 

 of milking may impart a stimulus to further vigorous secretion during the 

 period of milking. 



Milking tests in which the " quarters " were milked separately and the milk 

 from each quarter collected in fractions show that whereas in the case of the 

 first quarter milked there is a tendency for the percentage of fat in the milk 

 to rise steadily from the earliest drawn to the last drawn fractions, this 

 tendency is much less pronounced in the case of the other quarters. In the 

 quarter milked last the tendency for a considerable portion of the milking is 

 for the percentage of fat to fall rather than to rise. In all cases there 

 is a very rapid rise in the percentage of fat toward the close of milking. 



Taking the produce of each quarter as a whole, in 34 out of 37 comparisons 

 of first quarters milked singly, the first quarters gave richer milk than the last 

 quarters. In 95 tests in which the quarters were milked in pairs the first pair 

 milked gave the richer milk on 65 occasions. Very quick milking as com- 

 pared with very slow milking showed a difference of 10 per cent in milk yield 

 and 40 per cent in fat yield in favor of quick milking. A comparison of ordi- 

 nary milking, taking the teats in pairs, and simultaneous milking by two 

 milkers of all four quarters showed a difference of 2 per cent in milk yield 

 and 6 per cent in fat yield in favor of the latter method. 



Iowa educational market milk contest, B. W. Hammer and A. J. Hauser 

 (loioa Sta. Circ. SO {1916), pp. ^). — The results are given of two market milk 

 contests that have been held by the dairy department of the Iowa College. 



Safeguarding nature's most valuable food — milk, O. E. North (Vet. Jour. 

 72 (1916), No. 496, pp. 329-339) .—This article, which was prepared for the New 

 York Milk Committee, deals briefly with the food value of milk, the milk 

 industry in the United States, clean milk, clarification, pasteurization, certified 

 milk, selection of milk for home use, and municipal milk control. 



