Measuring the Milk, 59 
composite samples, an amount proportionate to the 
amount of milk delivered should be taken each day. 
This is conveniently done by the use of the Seovell 
Aliquot Milk Sampler, which, besides serving this 
purpose, gives the advantages of a milk thief in that 
it takes milk from all parts of the vessel. Where 
the milk varies only a few pounds from day to 
day, good results may be obtained by taking a uni- 
form amount of milk for the sample each day, but 
where the variation in quantity is considerable, 
aliquot samplers are much to be preferred. 
Making the test.—In preparing to make the test, 
the same care must be used that the sample shall 
be thoroughly mixed and _ perfectly uniform, that 
was taken in mixing the milk when the sample 
was drawn. In measuring the milk, the pipette 
should either be perfectly dry, or rinsed out with 
the milk to be tested immediately before measur- 
ing the assay. Where a large number of samples 
are to be tested, the latter is found to be the better 
practice. The greatest care should be taken that the 
milk is accurately measured. The lower end of 
the pipette should be placed about midway of the 
sample of milk and the pipette filled by gentle 
suction at the upper end. The milk should be 
drawn into the tube above the mark on the neck, 
and the end of the forefinger quickly placed over 
the end of the pipette, the pipette being steadied 
by the thumb and second and third fingers;  hold- 
ing it now on a level with the eve between the eye 
and the light, the pressure on the forefinger 
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