MILK AND ITS PRODUCTS 



141 



top and allow the milk to run down to the mark by slowly 

 relieving the pressure of the finger. 



3. Empty the milk into the bottle in the manner shown 

 in Fig. 37. 



4. Add the acid in the same manner in which the milk 

 was emptied into the bottle. 



5. Mix the acid with the milk by giving the bottle a 

 slow rotary motion. 



6. Allow mixture to stand a few minutes. 



7. Shake or mix again and then place the bottle in 

 the tester. 



8. Run tester four minutes at the 

 proper speed. 



9. Add moderately hot water until 

 contents come to the neck of the 

 bottle. 



10. Whirl one minute. 



11. Add moderately hot water un- 

 til contents of the bottle reach about 

 the 8% mark. 



12. Whirl one minute. 



13. Read test. 



How to Read the Test. At the top 



of the fat column is usually quite a 

 pronounced meniscus as shown in Fig. 

 38. A less pronounced one is found 

 at the bottom of the column. The fat 

 should be read from the extremes of 

 the fat column, i to 3, not from 2 to 4, 

 when its temperature is about 140 F. 

 Too high a temperature gives too high 



Fig. 38. Fat column 

 show ing meniscuses. 



