THE CHEMICAL COMPOSITION OF MILK 



31 



Properties and composition of milk-serum (Van Slyke and 

 Bosworth) 



Serum prepared from fresh milk by the method described 

 above has a characteristic appearance, being of a yellow color 

 with a faint greenish tinge and slight opalescence. 



The serum from fresh milk gives a slight acid reaction to 

 phenolphthalein and a strongly alkaline reaction to methyl 



orange. 



Constituents of Milk-serum 





Sample No. 1 



Sample No. 2 



Constituents 



Original 



Milk- 



Percent- 

 age of 



Original 



Milk- 



Percent- 

 age of 





Milk 



serum 



Milk Con- 



Milk 



serum 



Milk Con- 





100 C.C. 



100 C.C. 



stituents 

 in Serum 



100 C.C. 



100C.C. 



stituents 

 in Serum 





grams 



grams 



per ct. 



grams 



grams 



per ct. 



Sugar 



— . 











5.75 



5.75 



100.00 



Casein . . . . • . 



3.35 



0.00 



0.00 



3.07 



0.00 



0.00 



Albumin .... 



0.525 



0.369 



70.29 



0.506 



0.188 



37.15 



Nitrogen in other 















compounds . . . 



— 



— 



— 



0.049 



0.049 



100.00 



Citric acid . . . 



— ■ 



— 



— ■ 



0.237 



0.237 



100.00 



Phosphorus (organic 















and inorganic) . . 



0.125 



0.067 



53.60 



— 



— 



— 



Phosphorus (inor- 















ganic) .... 



0.096 



0.067 



70.00 



0.087 



0.056 



64.40 



Calcium .... 



0.128 



0.045 



35.16 



0.144 



0.048 



33.33 



Magnesium 



0.012 



0.009 



75.00 



0.013 



0.007 



53.85 



Potassium .._...! 

 Sodium . . . . J 



1 0.354 



1 0.352 



99.44 



/0. 120 

 \ 0.055 



0.124 

 0.057 



100.00 

 100.00 



Chlorine .... 



0.081 



0.082 



100.00 



0.076 



0.081 



100.00 



Ash 



— 



— 



— 



0.725 



0.400 



55.17 



In the table above we give the results of the examination of 

 two samples of fresh milk, the serum of which was prepared 

 in the manner already described. These samples of milk 



1 As chlorides. 



