MILK-TESTING AND DAIRY RECORDS. 



UK need of a bulk-tin dulling with the testing of milk and the keeping 

 of records of the performance of dairy cows has long been felt, and 

 it is for the purpose of giving in a simple and concise way instruc- 

 tions respecting these that this circular is written. 



The Babcock test was invented in the year 1890 by Dr. S. M. Bab- 

 co(k. of the Fniversity of Wisconsin, and its use has now become 

 general on this cunt incut wherever milk or cream is bought or sold on a basis of 

 the butter-fat contained therein. 



THEORY OF THE TEST. 



The underlying principle of the Babcock test is very simple. Owing to being 

 lighter than the other constituents of the milk, the fat-globules will, upon standing, 

 rise more or less perfectly to the surface, forming a layer of cream. They do not, 

 however, all rise by gravity, owing to the viscosity of the milk. Sulphuric acid 

 when mixed with milk dissolves or burns up the other milk solids without affecting 

 the fat, and leaves the fat-globules in suspension, permitting them to rise to the 

 surface more readily. Heat is generated by chemical action. This acid and milk 

 or cream appears as a hot, coffee-coloured mixture. By whirling this mixture by 

 centrifugal force at a high rate of speed, this process of gat Inn-ing the fat-globules 

 can be much hastened and much more effectively accomplished, and hence th< 

 of the centrifugal machine, or tester. 



APPARATUS FOR MAKING TEST. 



The apparatus used in making the test consists of: 



(1.) A milk-pipette of 17.G c.c. capacity for measuring the sample of milk to be 

 tested. (Fig. 1.) 



(2.) Milk-test bottles, having a graduated M-ale of 10 per cent, and with sub- 

 divisions of (>._: per cent. (Fig. 2.) 



(.",. i An acid measure of 17. T> C.C, capacity. i Fig. ". i 



(4.) A tester in which to whirl the test-]*>tt les. i Fig. 4.) 



(.".. A tempering vat. or can, for keeping samples warm. 



I'.esidcs the above, it is well to be provided with a tin dip with a sharp 

 for adding hot water to the test-buttles: a pair ..f dividers for measuring the fat 

 column: a test-bottle brush for cleaning the bottles; sample bottles; preservative 

 tablets and washing-powder. 



Such an apparatus for farm use may be purchased ;l t about S7.50 for a four- 

 bottle outfit, up i" -SIS fr a twelve-bottle outlii. 



MAKING THE TEST. 



< Ml' IM 01 1'Koc 



1. Secure a representative sample of the milk to be tested. 

 L'. Mix thoroughly by pouring from one vessel t<> another. 



3. The milk should be at a temperature of 00 to 7> Kahr. 



4. By means of the 17.r,-c.c. pipette, accurately measure this quantity of milk 

 into a milk-test bottle. 



.". Add 17..1 c.c. of commercial sulphuric acid having a specific gravity of 1.S2 

 to 1.83 and at a temperature of 00 to 70 Fahr. 



r,. Mix the milk and acid thoroughly by a gentle rotary motion. 



