VARIATIONS IN COW'S MILK 



35 



time, strange to say, the chemical composition of the 

 milk is subjected to daily variations that may reach 

 considerable extent. Knowledge of this is naturally of 

 the greatest importance in the detection of milk adul- 

 teration. The table on page 34 is given by Fleischmann 

 to show the minimum and maximum fat percentages in 

 the milk of a series of cows examined daily during an 

 entire period of lactation. 



As is shown, the percentages of fat differ consider- 

 ably even in milk from the same cow ; one cow, number 

 12 in the table, produced milk differing in fat content 

 as much as 100 per cent., that is, from 2.509 to 5.505 per 

 cent. 



The variations are not always gradual, but occur 

 spasmodically, as is evident from the figures above, 

 taken from Fleischmann 's work on milk. The numbers 

 in the perpendicular columns give the percentage of 

 fat for successive days; the figures above the dividing 

 line date from the beginning of the lactation period of 

 the cows, while below the line the figures given refer to 



