48 QUESTIONS AND ANSWERS 



"What is a composite sample, and why are such 

 samples used? 

 A composite sample is the quantity of milk se- 

 cured by mixing together samples of different days* 

 milk. They are taken in order to determine in one 

 test the average amount of fat in the milk received 

 for a definite period at different times. 



How should composite samples be kept? 



In airtight bottles in a cool, dark place conven- 

 ient to the place where milk is weighed and 

 sampled. They should be kept under lock and 

 key, and sufficient preservative should be added to 

 keep the milk in good condition until tested. 



What points should be considered when securing 

 containers for composite samples? 



1. They should be durable and easy to clean. 



2. Stoppers should fit tightly and be easily re- 

 moved. 



3. They should have large necks so that milk 

 may be added to or taken from them quickly and 

 without loss. 



4. They should be of convenient size and prop- 

 erly marked to identify each sample. 



What preservatives are used in composite samples? 



1. Corrosive sublimate or mercuric chlorid. 



2. Bichromate of potash. 



3. Formaldehyde. 



What are the advantages of corrosive sublimate? 

 I. It is an effective preservative. 



