THIRTY-SIXTH ANNUAL CONVENTION. 263 



Keep the bottles hot while testing, and they must be hot 

 when the reading is taken. If they become cold, place them in hot 

 water up to within an inch of the top of the neck and leave for 

 five minutes before reading. 



If the test has been properly conducted, the fat column will 

 be clear with no sediment present either below or above. If a 

 white, cheesy sediment shows under the fat column, use a little 

 more acid next time. White foam on top of the fat column is 

 usually caused by hard water and may be avoided by using rain 

 water. 



If the fat column is dark or has black sediment below the 

 fat, use less acid or cool the milk. 



Keep the acid bottle tightly stopped with a glass or rubber 

 stopper, as sulphuric acid absorbs water from the air and conse- 

 quently becomes weaker. 



In emptying test bottles, first pour out one-half the contents 

 and shake the remainder vigorously to loosen the sediment on 

 the bottom of the bottle. This saves labor in cleaning the bot- 

 tles as the sediment is very difficult to remove, if allowed to dry 

 on the bottom of the bottle. 



Keep the neck of the test bottles clean with a brush. 



It is advisable to keep a few extra bottles, one or two extra 

 pipettes and acid measures on hand. 



