NECESSARY APPLIANCES 155 



Too much care cannot be exercised in handling the 

 acid. For filling the test bottles, a pint cup with a 

 spout at the bottom and rubber tube attached about 

 eighteen inches in length should be used. By pinch- 

 ing the lower end of the tube when filling the bottles 

 the amount of water introduced can be controlled 

 with great accuracy. The test bottles must be cleaned 

 with warm water immediately after using. In pour- 

 ing out the acid and milk, thorough shaking should 

 be given to remove the sediment at the bottom of the 

 bottle. The aicid will cleanse and remove this better 

 than water. Both the milk and the acid must be care- 

 fully measured. Negligence about this will yield un- 

 reliable results. 



