MILK AND DAIRY PRODUCTS PART 



B. Practical Methods. 

 1. The "Lactocrite" Method. 



This method, which was worked out by de Laval in 1886, is 

 based upon the following considerations : A certain quantity of 

 milk is treated with a liquid which possesses the power of 



dissolving all the 

 substances pre- 

 sent in milk 

 with the excep- 

 tion of the fat. 

 When an aliquot 

 part of this mix- 

 ture is placed in 

 a " tester " pro- 

 vided with a 

 graduated capil- 

 lary tube and 

 whirled in a 

 centrifuge, the 

 fat separates. 

 Originally a mix- 

 ture of acetic 

 acid with 5 per 

 cent, concen- 

 trated sulphuric 

 acid was used 

 to dissolve the 

 casein; after- 

 wards ethylidene- 

 lactic acid with 

 5 per cent, sul- 

 phuric acid and 

 10 per cent, hy- 

 drochloric acid 



FIG. 21. Tester, Disc, and Stand used in the 

 Lactocrite Method. 



were employed. 1 



The testing tubes are graduated empirically after very careful 

 comparison with the gravimetric analysis. 



1 M. Ekenberg, Die LaJctoJcritmethode, &c. luaug. Diss., Konigsberg, 1893. 



