MILK 



59 



FIG. 22. Water-bath for the 

 Lactocrite Method. 



The apparatus required for the lactocrite method is made 

 by the Aktiebolaget Separator of Stockholm. 



It consists of the " testers," which are made of silvered or 

 platinised metal, with graduated glass tubes ; a disc which can 

 be fitted to the stand of any Al fa-Laval separator, and has 

 cavities bored into it to hold the testers (Fig. 21); a water 

 bath (Fig. 22); a cover for the disc so that it can be heated 

 by steam ; a number of 

 . boiling tubes (Fig. 23). 



To carry out the test 

 10 c.c. of milk at 15 C. 

 are measured into a boil- 

 ing tube which already 

 contains 10 c.c. of the acid 

 mixture heated to 80. 

 After mixing, the boiling 

 tube is heated in the water- 

 bath at 100 C. for 15 to 

 18 minutes with occasional 

 shakings. 



As will be seen in 



Fig. 23 the boiling tube is provided with a piece of glass 

 tubing which acts as a reflux condenser. The boiling tubes 

 are heated in the water-bath, shown in Fig. 22, which is 

 arranged for steam, but can also be heated by a burner. When 

 the heating is finished cold water is slowly led into the water- 

 bath to cool down the boiling tubes. Finally, the holder 

 containing the boiling tubes is placed in water at 60, where it 

 remains until the temperature shown on a thermometer placed 

 in one of the boiling tubes also registers 60. 



In the meantime the testers have been placed in the disc 

 and warmed to about 60 C. by slowly revolving the disc on its 

 support and letting steam into the cover which is provided for 

 the purpose of heating up the disc. 



After violently shaking one of the boiling tubes, part of the 

 contents is poured into the small cup belonging to the tester, 

 and the latter immediately pushed into the cup. The graduated 

 glass tube fills with the liquid, and the excess spirts out through 

 the opening in the upper part of the tester. The filling of the 

 testers must therefore be done over a porcelain basin. This 



