Chemical Analysis of Milk and Its Products. 227 



Klein 1 has modified this method by weighing the liquids, thus 

 securing greater accuracy ; 22 to 24 per cent.-ammonia is used, 

 one-tenth as much being taken as the amount of milk weighed 

 out. The results come uniformly .0005 too high, and this correc- 

 tion should always be made. The following formula will give 

 the specific gravity of the milk, which in case of careful work 

 will be accurate to one-half lactometer degree; if the letters 

 given above designate weights (instead of volumes as before) 

 and specific gravities of the liquids, respectively, we have 



A 



~ ~~ 



264. Condensed milk. The same methods are, in gen- 

 eral, followed in the analysis of condensed milk as with 

 whole milk. Condensed milk is preferably diluted with 

 five times its weight of water prior to the analysis, both 

 because such a solution can be more easily handled 

 than the undiluted thick condensed milk, and the errors 

 of analysis are thereby reduced, and because the fat is 

 not readily extracted except when the milk has been 

 diluted. 2 The same constituents are determined as in 

 case of whole milk, viz., solids, fat, casein and albumen, 

 ash, milk sugar, and cane sugar (if any has been added 

 to the milk) . The cane sugar is determined by the dif- 

 ference between the solids not fat and the sum of the 

 casein, albumen, milk sugar and ash ; if the student has 

 a knowledge of the manipulation of the polariscope and 

 has had experience in gravimetric sugar analysis, the 

 milk sugar is determined gravimetrically, and the cane 

 sugar by the difference between the polariscope reading 

 after inversion and the milk sugar present. 



1 Milch z^itunpr, 1896, p. 656: see also De Koningh, Analyst, 1899, p. 142. 



2 A second extractiorf following leaching: and subsequent drying of 

 the tubes is necessary to extract all the fat in condensed milk: see 

 Bull. 104, Bur. of Ohem., IT. S. Dept. of Agr., p. 102 and 154. 



