

DAIRY PRODUCTS. 103 



lo combined simplicity of construction and working and sufficient correctness for 

 all practical purposes. 



The lactocrite will, no doubt, be found invaluable for butter dairies, or dairy fac- 

 tories buying milk from different farmers, by enabling them to carry out the system 

 of paying for the milk according to the amount of butter-fat which is the only fair 

 system. At present, both in England and in other countries, the farmer whose milk 

 will make butter at a rate of 3 pounds per 100 pounds of milk gets the same price as the 

 farmers whoso milk is so rich as to give 5 pounds of butter per" 100 pounds of milk, 

 which of course is most unfair. When milk is paid for according to the fat con- 

 tained in it, the temptation to skim it is done away with, and, besides, a great encour- 

 agement is given to the production of rich milk. 



The lactocrite will also j>rove of use for analysts who have access to a separator 

 stand, as it will give in short time a more exact determination of the amount of fat 

 than any other apparatus. In this connection it will be of interest to know that a 

 special construction of it has been adapted to fit Dr. Do Laval's small hand separator, 

 worked by hand and requiring no foundation. 



Sebelieu has published a comparison of the results obtained with the 

 lactocrite and Cronander's method with the gravimetric methods. 1 



Cronander's method gave in general results slightly below those fur- 

 nished by the gravimetric and Soxhlet's processes. 



Dr. Cronander, to avoid this error, has introduced a slight modifica- 

 tion into his process by adding a little alcohol to the mixture of potash, 

 ether and milk. The principle of the separation of the fat thus becomes 

 the same as in the lacobutyroineter of M. Chevreul. By using this 

 modified process it was found possible to bring the results up near to 

 those of the gravimetric method. 



The results furnished by the lactocrite showed an almost perfect 

 agreement with the gravimetric numbers, the differences being usually 

 within 0.05 per cent. 



Attention must be paid to keeping the test tube holding the milk and 

 acids well shaken, especially before pouring its contents into the metal 

 box, and that the rest of the apparatus be pressed in the box at once 

 when the milk has been found. In proceeding in this way no separa- 

 tion of the different parts of the test liquid is possible, and thus a fair 

 average sample is recovered in the test glass. 



Concerning the question of the advantages of the lactocrite as com- 

 pared with other forms of apparatus for estimating the fat in milk Se- 

 belien is somewhat conservative, but seems to think that the matter 

 will soon be determined by comparative trials. 



LACTOBUTYROMETRIC METHOD. 2 



This volumetric method depends on the separation of the fat from the 

 milk by a mixture of ether and alcohol. The method has been carefully 

 studied by Oaldwell and Parr. 3 



A mixture of 75 parts of pure ether, 100 of absolute alcohol, and 135 of water are em- 

 loyed. The instrument employed is made of moderately thick-walled tubing (about 



1 Landw. Versuchs-Stationen, vol. 33, pp. 393 et neq. 



~ Marchand, Instruction sur I'emploi du lactobutyrometcr, Paris, 1850 and 1878. 



:t Am. Chem. Jour., vol 7, pp. 238 et scq. 



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