13 



DIRECTIONS FOR MAKING THE BABCOCK TEST WITH MILK. 



Measuring the charge. Directions have already been 

 given for preparing the sample for the test. The milk is 

 poured from one container 

 to another two or three 

 times. The tip of the 

 pipette is immediately in- 

 serted and the milk sucked 

 up with the mouth until 

 it reaches a point well 

 above the graduation mark 

 on the stem ; the dry fore- 

 finger is then quickly 

 placed over the mouth of 

 the pipette. By slightly 

 relaxing the pressure of 

 the finger the milk is al- 

 lowed to flow down until 

 it just reaches the mark. 

 The tip of the pipette is 



FIG. 10. A type of steam tester 

 with an arrangement for heating 

 the water used in the test. 



now placed in the neck of the test bottle and the milk 

 allowed to flow slowly down the side. The right way 

 is to hold the pipette obliquely to the mouth of the 



test bottle as shown in 

 figure 13. The wrong 

 way is shown in figure 

 14. If the bottle and 

 pipette are held in the 

 latter position the neck 

 of the bottle may clog up 

 and some of the milk 

 run over the top. Care 

 must be taken that none 

 of the milk is lost during 



FIG. 11. A type of electric tester. 



the operation. When 

 nearly all the milk has 

 run out of the pipette, the last drop is forced out with a 

 puff of the breath. 



Adding the acid. The temperature of the milk when the 

 acid is added should be between 60 and 70 F., and the 

 acid should be at about the same temperature. Seven- 



