406 



Journal of Agriculture, Victoria. [10 July, 1918. 



Testing Cream. 



Sampling. — 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 Wheal 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 so as to contain betAveen 40 and 



cu- 



-d 



8. — Reading Milk Test. 9. — Reading Cream Test. 



10. — Cream Sampler. 



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 vacuum is 

 created; on releasing the rod it runs right back to the thumb. 



Making the 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 owing to the difference in the specific gravity. It is 



