THE BABCOCK MILK TEST. 161 



began to use the tester it was soon discovered 

 that the Babcock milk test was not an auto- 

 matic machine. Although veiy simple to a 

 chemist, it was found not to be like a clock 

 which only needed to be wound up and left to 

 run itself for ten minutes to give accurate re- 

 sults, but the wheels must be watched, the 

 milk properly mixed, and the strength of the 

 acid correct. 



Any milk can be tested. — It has generally 

 been supposed to be easier to test a mixture of 

 the milk of several cows than the milk of one 

 cow, and that possibly there might be found a 

 cow's milk which could not be successfully 

 tested. The milk of each of 107 cows was 

 tested at the World's Fair, and for four months 

 there were made at least 150 tests of milk 

 every day. This gave many tests of a great 

 variety of milks. There was a great variation 

 in the composition of these milks and in the 

 characteristics and health of the cows. We 

 were able to test successfully every one of 

 these samples of milk and by proper manipu- 

 lation to get a very clear separation of the fat. 



Investigate. — Any one who uses a Babcock 

 test may profit by our experience in two points 

 at least. First, he can have perfect confidence 

 in the process as described by Dr. Babcock, that 

 it has given and can give satisfactory tests of 

 milk; and second, that if any one has trouble 

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