8 



per cent, (by volume) of household ammonia. In the latter case the 

 results must be increased to offset the dilution by the factor of 1.05. 



Churned milk. In partly churned samples the lumps of butter 

 can be temporarily incorporated by heating and pouring, or by dis- 

 solving in 5 per cent, (by volume) of ether. With the first method 

 it is necessary to pipette while the sample is warm and it is advisa- 

 ble to weigh the test. It is extremely difficult to secure an accurate 

 test of a badly churned sample. 



Separator cream containing more than 25 per cent, butter fat can- 

 not be pipetted directly with accurate results, for the reason that a 

 cream pipette (18 c. c.) will not deliver the requisite amount (18 

 grams) because of the lower specific gravity and greater adhesive- 

 ness of the liquid. The experiment station does not advocate the 

 use of 50 per cent, test bottles for rich cream, but prefers to use one- 

 half amount (9 grams) of the weighed sample in the 30 per cent. 6 

 inch bottle where tests run over 25 per cent., multiplying the results 

 by two, In pipetting thin cream it is well to use two pipettes alter- 

 nately, allowing one to drain into the test bottle while the other is 

 in use. 



It is the general rule in western creameries to weigh all samples 

 of cream in preference to pipetting. While at first this method may 

 take longer, it is an excellent precaution, and with practice the oper- 

 ator can make the test nearly as fast as by pipetting. We have 

 found, at the experiment station, that thin cream (25 per cent, or 

 less fat) free from lumps of fat and uncurdled will give just as high 

 results when pipetted (18 c. c), provided the pipette is given ample 

 time to drain into the test bottle. 



Sour cream can be suitably prepared by the use of a sieve, but the 



inclosed gas prevents satisfactory pipetting and makes weighing of 



the test absolutely necessary, if accurate results are to be obtained. 



Before mixing, the acid and the contents of the 



Adding acid. test bottle should be at a temperature of 60° — 



70° Fahr. When the acid is added the test 



bottle should be turned so as to wash down all the sample adhering 



to the sides of the neck, rotated at once and this continued until all 



the lumps of curd are dissolved. The hand mixing should never be 



slighted, and care should be taken not to throw the fat into the neck 



of the test bottle. 



