Composition of Milk and Its Products. 17 



20. Ash. The ash or mineral substances of milk are 

 largely composed of chlorids and phosphates of sodium, 

 potassium, magnesium and calcium; iron oxid and sul- 

 furic and other acids are also present in small quanti- 

 ties among the normal mineral milk components. The 

 amounts of the different bases and acids found in milk 

 ash have been determined by a number of chemists; the 

 average figures obtained are given in the following 

 table, calculated per 100 parts of milk (containing .75 

 per cent, of ash) and per 100 parts of milk ash. 



Mineral Components of Milk. 



In per cent of milk. In per cent of asK 



Potassium oxid (KjO) .19peret. 25.64 per ct. 



Sodium oxid vNa^O) .09 12.45 



Lime (CaO) .18 24.58 



Magnesia (UgUj .02 3.09 



Iron oxid (FejOs) .002 .34 



Phosphoric anhydrid (PjOj)— .16 21.24 



Chloriu (01) .12 16.34 



' .762 per ct. 103.68 per ct. 



Less oxygen, corresponding to 



ehlorin .012 3.68 



.75 100.00 



The combinations in which the preceding bases and 

 acids are contained in the milk are not known with cer- 

 tainty. According to Soldner, 36 to 56 per cent, of the 

 phosphoric acid found in milk, and from 53 to 72 per 

 cent, of the lime, are present in suspension in the milk 

 as di- and tri-calcium phosphates, and may be filtered 

 out by means of Chamberland filters (18), or by long 

 continued centrifuging (Babcock^). The rest of the 

 ash constituents are dissolved in the milk serum. 



• Wisconsin experiment station report 12, p. 93. 



