Id 



depends upon the weather, the size of the samples, and the length of 

 time over which the testing- period extends. A Babcock test of the 

 sample is made at the end of two weeks or a month ; and if the daily 

 sampling and the testing of the sample are carefully done, it gives the 

 average quality of the milk supplied during the time over which the 

 test extends. 



The samples may be tested twice per month, but by keeping them 

 in a fairly cool place satisfactory results can be obtained by testing, 

 but once a month. 



Notes on Composite S.\.mpli.ng and Testing. 



1. For holding composite samples, pint jars with long corks are 

 preferable. Turned wooden corks are more satisfactory than porous 

 corks. 



2. The jars should be kept well corked, as the samples will dry 

 on the surface and a tough skin, composed largely of cream, will be 

 foimed when exposed to the atmosphere in warm weather. 



3- Paste a plainly written label on each patron's jar, fasten its 

 edges down well, and give it at least two coatings of heavy shellac to 

 prevent it from washing off when cleaning the bottles. 



4. Add the preservative to the composite sample jars at the be- 

 ginning of the testing period, and before any milk is added to them. 

 It may be necessary to add a little extra preservative later on. Be 

 guided by the color of the samples and how well they are keeping. 

 An excess of preservative has a strong tendency to produce burnt read- 

 ings. 



5- The sample for the composite jar should be taken after the milk 

 is poured into the weigh can. For this purpose an ounce or a half- 

 ounce dipper is often used. A tube or milk "thief" and a drip from 

 the conductor are also satisfactory means of obtaining a sample. When 

 receiving milk that is partly frozen, guard against taking a sample 

 from only the unfrozen portion. 



6. Give the jar a gentle rotary motion each time a sample is tak- 

 en, to mix with it the cream that has risen and also to incorporate the 

 fresh sample with the part containing the preservative; ana avoid shak- 

 ing the jar, as shaking tends to churn the contents. 



7. It is sometimes necessary to place the samples m a cool place 

 each day when through using them. 



8. To prepare composite samples for testing : Set the sample 

 jars in warm water at about 110 degrees F., to loosen the cream from 

 the sides of the j.ars, and also to warm the samples to cause the cream 

 that has risen to mix more readily with the milk. Mix well by pouring 

 from one vessel to another— never by shaking. Should difficulty be 

 experienced in getting a thorough solution, the addition of a small 

 amount of potash will facilitate the operation. 



When the composite samples for the Babcock test have bepn add- 

 ed to the test bottles, cool to about 60 degrees F., before adding the 



