262 ILLINOIS STATE DAIRYMEN'S ASSOCIATION. 



curd has been dissolved, and until the liquid in the bottle is of 

 a brown color. 



When the acid has been added to all and mixed, the bottles 

 are placed in the centrifuge, arranging them so as to balance. 

 Whirl at the speed given in the directions that come with the 

 machine. Nearly all hand machines are built to run from eighty 

 to one hundred turns of the crank per minute. Whirl for five 

 minutes. Stop the machine gradually. Add hot water to the 

 bottles with the pipette until each is full to the base of the neck. 

 Whirl again for two minutes and stop. Add more hot water until 

 the neck of each bottle is full to within an inch of the top. Whirl 

 again for one minute. 



^ Reading the Test. 



The neck of the standard milk test bottle is divided into ten 

 large divisions, each of the latter into five small divisions. Each 

 large division is one per cent, and each small division two-tenths 

 of one per cent. If the butter fat fills three large spaces there is 

 three per cent of fat, or three pounds of fat to the hundred of 

 milk and would be written 3 per cent. If the fat column covers 

 five large and two small spaces, the reading would be five and 

 four-tenths, written 5.4 per cent. 



The dividers are used to conveniently measure the length of 

 the fat column. To do this the extreme length is taken by plac- 

 ing one point at each extremity of the fat column. Then with- 

 out disturbing the ^'spread" of the dividers, one point is placed at 

 the line on the bottle neck marked with O, and the reading made 

 where the other point touches the scale. This method enables one 

 to read the per cent of fat easily and accurately. 



Cautions and Remedies. 



If a sample coagulates before testing, start a new one, ad- 

 ding a few drops more formalin than at first. 



Sulphuric acid destroys clothing and burns the flesh, so 

 handle it with care. If spilled on the hands, wash ofi^ with water 

 at once. 



