43^ JtiuruaJ of Agriculture, Yuioria. [lo July, 191 i. 



Testing Cream. 



Sampl'Dig. — If the cream is fresh and liquid enough to pour freely the 

 sample may be taken by pouring from one vessel to another three times and 

 immediately dipping a small quantity into a bottle; add three drops of 

 formalin, and cork tightly to prevent evaporation of moisture. If left in 

 an open jar, especially in hot weather, evaporation takes place rapidly and 

 this would increase the test, causing inaccurate results. 



If the cream has set, as it does when it is thick and ripe, the sample 

 must be taken with a ^Vheal sampler (Fig. 10). This cuts a complete core 

 from top to bottom of the can giving an accurate sample and an aliquot part 

 of the cream. The whole syringeful is taken into the bottle. The cream 

 should be separated to contain between 40 and 50 per cent, fat ; then there 

 should be no difficulty in getting a correct sample. When liquid enough 

 the cream may be mixed by means of a plunger, consisting of a saucer- 

 shaped disc attached to a rod. 



The Wheal sampler is like a syringe, and the piston must be kept tightly 

 packed so that, when the thumb is placed on the open end of the tube 

 and the rod drawn out tO' its full length, a complete ^•acuum is created ; 

 or. releasing the rod it runs right back to the thumb. 



Making ihe test.- — The Babcock test is based on the assumption that 

 18 grammes weight of the material to be tested is delivered into the flask. 

 A 17.6 c.c. pipette will deliver 18 grammes of milk into the flask; but, 

 with cream testing 40 to 50 per cent, fat, 17.6 c.c. would only weigh 15 

 to 16 grammes on account of the difference in the specific gravity. It is 

 therefore provided by law that cream shall be weighed directlv into the 

 flask. 



For this purpose seiisiti\ e scales are used (Fig. 4 b). These are obtain- 

 able for about 25s. The sample bottles should be stood in water, 90 to 

 100 degrees, until liquid enough to run freely. The flask is then balanced 

 on the scales ; approximately by the counterpoise on the beam, then by 

 small shot or pellets of paper on the tray. The weight is moved along the 

 beam to the 9 gramme mark, and cream (being thoroughly mixed) is run 

 in with a pipette until the weight is balanced. If a drop too much is run 

 in it may be removed by a fine tube which can be inserted to the bottom 

 of the flask. Nine grammes of cream, instead of 18, are taken because 

 our flasks (Fig. 6) are graduated to 30 per cent., and the fat of 40 per 

 cent, cream would not all go into the graduated neck. Nine c.c. of water 

 are then run in. After adding 17.5 c.c. sulphuric acid, shake until the 

 casein is all dissolved. There is a frosted spot on the flask on which a 

 number should be marked with an ink pencil to correspond with the number 

 of the sample. The procedure now is the same as with milk. 



In reading the cream test, the fat is measured from a to c. not to d 

 or b (Fig. 9). The cream flasks are graduated for 18 grammes and as 

 9 grammes have been taken, the reading has to be doubled. 



To calculate the result. — The weight of cream is multiplied by the test 

 and divided by 100. This gives the amount of butter fat that the factory 

 should pay for. 



Example. — A can of cream contains 95 lbs. net. The te.st reads 22. 

 Then 22 x 2 = 44, gives the correct percentage of fat in the cream. 

 95 )C 44 -^ 100 = 41. 8 lbs. butter fat in that can of cream. 



Skim Milk. 

 It is quite as important to test the separator milk as to test the cows. 

 Frequently, verv hea\-y loss is experienced through the separator getting 



