6 QUESTIONS AND ANSWERS 



burette, and, as its strength is known, it is an easy 

 matter to figure the amount of acid in the milk or 

 cream. 



One c. c. of Yiq normal alkali neutralizes .009 

 gram lactic acid. 



In the test used at Cornell university the alkali 

 used is a %o normal solution of caustic soda. This 

 makes a very convenient strength, because when 9 

 grams of cream or milk are taken .1 c. c. of it neu- 

 tralizes or represents .01 per cent lactic acid. Thus, 

 if in testing the milk 4 c. c. of the alkali isoised, the 

 milk contains .40 per cent of acid. 



In Farrington's test the alkali used is made %o 

 normal by adding 5 tablets in 97 c. c. water. Then 

 when 17.6 c. c. milk is taken, i c. c. of the alkali 

 represents .01 per cent acid. 



In Mann's test a Yio normal alkali is used and 

 50 c. c. of milk is tested. The number c. c. of 

 alkali necessary to neutralize the acid measures in 

 degrees the amount of acid. 



One c. c. of -5- alkali=i degree Mann's test. 



To get the per cent acid multiply the number c. c. 

 alkali used by .009, divide by 50 and multiply by 

 100. 



How can milk or cream be tested on the receiving 

 platform? 



1. For acidity by the use of an acidimeter. 



2. For odors by sense of smell. 



3. For flavors by sense of taste. 



4. For insoluble dirt, by eyesight and by allow- 

 ing samples to stand a few minutes in small glass 

 jars so that the dirt will settle to the bottom. 



