182 



CARE OF COMPOSITE MILK SAMPLES 



Fig. 2. 



It is, therefore, unsafe and. nnjnst to assume that the 

 product of any one day will accurately represent the prod- 

 uct of any other day. When a small portion of each day V 

 milk is taken and .carefully mixed with similar samples 

 representing the product of other days, and the mixed milk 

 is tested, we may expect to accurately determine the per 



cent, of fat in the milk which a cow is pro- 

 ducing at that period of lactation, or the 

 per cent, of fat in milk which a dairy 

 farmer may be furnishing a creamery. 



Jn securing and preserving composite 

 samples of milk or cream, it will be well to 

 observe the following points: The milk or 

 cream must be thoroughly mixed by pour- 

 ing from one pail or can to another several 

 times to evenly mix the butter fat with the 

 milk serum. A small dipper (Fig. 1) may 

 be used to farther agitate the milk. This 

 dipper should have a solid metal * handle 

 for convenience in cleaning and the capacity should be 

 about one ounce, or just large enough for measuring the 

 desired sample into the jar in which it is to be preserved. 

 By using the same dipper an approximately equal amount 

 of milk may be taken at each milking, or at each delivery, 

 until the composite sample is complete. Several cans or 

 jars may be successfully used for composite 

 samples, but naturally some are better 

 adapted for this particular purpose than are 

 others. The first essential is that the jar be 

 practically air tiuht, otherwise a small 

 amount of water may evaporate or be taken 

 up by the atmosphere, thereby slightly in- 

 creasing the per cent, of fat in the milk or 

 cream that remains in the jar. The second 

 essential is that the jar be as simple as pos- 

 sible, that it have few parts, and preferably 

 no parts of metal or rubber. The third 

 essential is that the jar have a wide mouth, 

 which can be easily and quickly opened and closed, to 

 admit of rapid work in handling samples. 



Fig. 2 shows the common "]\Iason" jar, which is least 

 desirable for the purpose. Fig. 3 shows the "Lightning," 

 Avhich is but little better than Fig. 2. Fig. 4 shows a glass 

 jar with metal top. This jar is not desirable for the pur- 





Fig. 3. 



