i MILK 65 



3. Lincl sir 0111 s Butyrometer Method. 



In 1889 T. Lindstrom 1 proposed a simple and efficient 

 centrifugal method for estimating the fat in milk, which has 

 been improved by the Aktiebolaget Separator of Stockholm. 

 Originally the same mixture of acids was used as in the lacto- 

 crite method, but this was soon replaced by concentrated 

 sulphuric acid as a solvent for the casein and the undissolved 

 phosphate in the milk. The principle of this method in its 

 present form is therefore the same as in the Babcock test. 



A noticeable difference between Lindstrom's butyrometer 

 method and the other centrifugal methods is, that in the 

 former the column of fat which separates in the graduated part 

 of the tube is allowed to cool and become solid ; this has the 

 advantage that the samples need not be read immediately 

 after being taken from the centrifuge, but may be kept for any 

 length of time. 



Lindstrom's butyrometer is made by the Aktiebolaget 

 Separator of Stockholm, in two sizes. The large one, which holds 

 eighty test-bottles, can be driven by power in the ordinary 

 Alfa-Laval separator stand, or by hand in the special support 

 belonging to the Baby butyrometer. The smaller size is also 

 turned by hand ; it holds twenty test-bottles, and is known as 

 the Kolibri butyrometer. In Fig. 29 the large butyrometer 

 and the apparatus belonging to it are shown, whilst in Fig. 30 

 is a sketch of the small butyrometer. 



The following parts belong to the butyrometer : 



(1) The test-bottles (Fig. 29, 1), consisting of a narrow 

 graduated tube, which is joined on to a wider one. The latter 

 has a small opening on the upper rounded portion, and a 

 distinct mark round the middle. A number is etched on the 

 upper part of the test-bottle. 



(2) Pipettes to measure the milk (Fig. 29). In ordinary 

 cases (6) is used, whilst (5) is reserved for milk which has been 

 treated with preservatives, for it prevents the milk from entering 

 the mouth when it is drawn into the pipette. 



(3) A wooden stand for the test-bottles (Fig. 29, 10). 



(4) Glass measuring cylinder for sulphuric acid (Fig. 29, 4). 



(5) Crude sulphuric acid of T80 sp. gr. 



1 Mttch-Zeitung, 1892, p. 496, and 1893, pp. 85, 341. 



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