154 



Testing Milk and Its Products. 



position in Chicago in 1893 illustrate the 'correctness of 

 this statement. The .tests included twenty-five Jersey 

 and Guernsey cows each and twenty-four Shorthorn 

 cows. 



Tests of herd milk on successive days. 



On July 17, 1893, the mixed milk of the Jersey cows 

 tested two-tenths of one per cent, higher than on the 

 preceding day; the Guernsey herd milk tested one-tenth 

 of one per cent, lower, while the Shorthorn milk did not 

 change in composition; comparing the tests on July 19 

 and 20, we find that the Jersey and Shorthorn milk 

 tested four-tenths and one-tenth of one per cent, higher, 

 respectively, on the latter day than on the former, and 

 the Guernsey milk tested one-tenth of one per cent, 

 lower. There was no change in the feed of the cows or 

 in the method of handling them on these days. 



173- Ranges in variations of herd milk. According 

 to Fleischmann, 1 the composition of herd milk will vary 

 on single days from the average values for the year, 

 expressed in per cent, of the latter, as follows: 



The specific gravity (expressed in degrees) may go above or 

 below the yearly average by more than 10 per cent. 



The per cent, of fat may go above or below the yearly aver- 

 a g6 by more than 30 per cent. 



1 Book of the Dairy, p. 32. 



