The Babcock Test. 69 



79. Influence of temperature on the separation of fat. 



The intensity of the action of the sulfuric acid on the 

 milk is influenced by the temperature of either liquid; 

 the higher the temperature, the more intense will be the 

 action of the acid on the solids of the milk. It nray be 

 noticed that acid from the same carboy will act differently 

 on milk in summer than in winter time, if the acid and 

 the milk are not brought to a temperature of about 70 

 before testing during both seasons. The temperature of 

 the liquids may be as low as 40 F. in winter and as high 

 as 80 F. in summer. This difference of forty degrees 

 will often have considerable influence on the clearness of 

 the fat separated, showing white curdy substances and a 

 light colored fat in winter, or black flocculent specks, 

 with a dark colored column of fat in summer. Both 

 these defects can be avoided when the acid is of the 

 proper strength, by bringing the temperature of the milk 

 and the acid to about 70 F. before the milk is tested. 



The operator should be particularly cautious against 

 over-heating either milk or acid; so intense an action 

 may be caused thereby as to force the hot acid out of the 

 neck of the test bottle when it is added to the milk, thus 

 spoiling the test and possibly causing an accident. 



4. WATER TO BE USED IN THE BABCOCK TEST. 



80. Eain water, condensed steam, or soft water should 

 be used for the purpose of bringing the fat into the neck 

 of the test bottles. The surface of the fat column will 

 then usually be clear and distinct. The foam or bubbles 

 that sometimes obscure the upper line (meniscus) of the 

 fat, making indistinct the point from which to measure 



