CATTLE. 221 



The Babcock Test. 



1. Take samples of equal amount from at least six consecutive 

 milkings; the samples should not be taken until the milk in the 

 pail is thoroughly mixed by pouring or stirring. 



2. Place samples in glass jar, and keep in a cool place and cover 

 so as to prevent evaporation. This is a composite mixture. 



3. When ready for the test place jar containing composite mixture 

 into an other vessel containing water heated to about 100 to 110 

 degrees Fahr. 



4. Before removing the required amount for the test the milk 

 in jar must be thoroughly and completely mixed. 



5. Draw out the amount of milk required with the pipette and 

 deliver it to the test bottle. 



6. The value of the test will depend upon the care and accuracy 

 of the operation. 



7. Use sulphuric acid having a specific gravity of 1.82 to 1.83 for 

 testing. 



8. The quantity of acid required for each sample is 17.5 c.c. and 

 the quantity of milk should be 17.6 c.c. 



9. The temperature of milk should be as near 60 degrees Fahr., 

 as possible; too much above 60 degrees will burn or char the 

 casein and sugar, and too far below 60 degrees will not dis- 

 solve the casein. 



10. Place milk in test bottle first, then add the sulphuric acid care- 

 fully so as not to run the acid through the milk. 



11. Mix the acid and milk thoroughly t>y a rotary motion. The 

 chemical action will produce great heat. They s'hould then 'be 

 placed immediately while hot in the centrifugal or" tester. 



12. They should be whirled at full speed from 5 to 6 minutes. 

 This will separate the fat and bring it to the surface. If any 

 casein remains in the milk shake the sample again. 



13. Add soft hot water to the. bottle until the contents rise to the 

 neck of the tester bottle, then whirl again at full speed from 

 2 to 3 minutes. 



14. Add more hot water until the fat reaches the 8 or 9 per cent 

 mark on the graduated neck of the test bottle. Whirl one 

 minute. 



15. If the operation has been carried out properly the fat should 

 be clear, yellowish or straw color. 



16. The line of separation between water and fat should be always 

 distinct. 



17. In testing milk it is recommended that tests 'be made in dupli- 

 cate, and if the numbers correspond in the graduated tube, the 

 results may be considered reliable. 



