86 



MANUAL OF MILK PRODUCTS 



lable proteins. After filtering, the yellow serum which resulted 

 was in some instances cloudy. To get a clear solution in these 

 cases the filtrate was neutralized with ammonium hydroxide, 

 warmed, and filtered. The filtrate was then always perfectly 

 clear. The yellow serum obtained by either of these methods 

 was then placed in a 10 cm. cell and its color compared with the 

 standard color glasses of the Lovibond tintometer. The colors 

 were readily matched. In some cases a few tenths of red were 

 required. 



Using the above procedure, color readings of the whey from 

 the milk from forty-three cows and six sheep were made. The 

 color of the sheep's milk whey is given to show how very much 

 higher colored it is in many cases than the whey from cow's 

 milk. The figures for sheep's milk are given in the following 

 table : 



Color of Whey from Sheep's Milk 





Color, 10 Cm. Layer 





Yellow 



Red 



1 



7.0 

 7.0 

 15.5 

 24.0 

 3.5 

 4.5 



0.9 



2 . 



3 



0.5 

 0.5 



4 



1.2 



5 



0.2 



6 



0.5 







The samples of cow's milk represent four breeds and include 

 four Ayrshires, four Shorthorns, fifteen Holsteins, and tw T enty 

 Jerseys, all pure-bred dairy animals. The milk production 

 varied from 4.2 to 47.4 lb. a day. The stage of the lactation 

 period of the animals varied from one to thirteen months, and 

 their ages from three to fifteen years. The results of the colori- 

 metric studies have been arranged according to breed, stage of 



