52 QUESTIONS AND ANSWERS 



13. Write down results immediately upon read- 

 ing them. 



14. If tests are not satisfactory in every par- 

 ticular, make them over. Honest results cannot be 

 accomplished without accurate work. 



How would you proceed to secure a proper sample 

 of the milk for testing? 



Where possible, mix the milk by pouring it from 

 one vessel to another two or three times. If the 

 cream has risen, care should be taken so that it is 

 all reincorporated with the milk and evenly dis- 

 tributed. When it is impossible to pour the milk, 

 use some appropriate instrument to thoroughly stir 

 it, then while the fat is evenly distributed the 

 samples must be taken, using a 17.6 c. c. pipette or 

 18 grams weighed on a scale. 



How is the milk transferred to the test bottle? 



By sucking it up into a pipette, quickly placing 

 the forefinger over the end and allowing the milk 

 to escape until its surface is level with the 17.6 c. c. 

 mark on the stem. Then place the tip of the pipette 

 a short distance into the neck while holding the 

 bottle in a slanting position, so that its opening will 

 not be entirely closed. By reducing the pressure 

 with the forefinger the milk will run down the 

 side of the neck and will not be blown out by es- 

 caping air. The drop remaining in the tip of the 

 pipette should be blown into the test bottle. 



How much acid is used, and how is it added? 



A volume of sulphuric acid equal to the volume 

 of milk tested is used. It is usually measured in a 



