TESTING DAIRY PRODUCTS BY THE BABCOCK TEST. 83 



In buying milk on this plan it is necessary that care should be 

 taken to get correct samples, A pint or quart fruit jar should 

 be provided for each patron and labeled with his name or 

 number, if one has been assigned him. Into this put a small 

 quantity, as much as one can hold on one-half inch of a pen knife 

 blade, of the preservative, powered bichromate of potash. A 

 measured portion of every lot of milk furnished by a patron 

 should be taken and put in the jar bearing his number. The 

 milk should first be thoroughly mixed by stirring or pouring 

 from one can to another, and the sample taken immediately 

 The sampling tube described on page 65 is the best instrument 

 for this purpose and should always be used. 



Whenever a fresh portion of milk is placed in the jar, it should 

 be mixed with milk previously added by giving the jar a rotary 

 motion. The jars should always be closed tightly to avoid 

 evaporation and kept in a cool place. At the end of two weeks, 

 or as often as one desires, the composite samples are tested. 

 The percentages of butter fat found represent the average com- 

 position of each patron's milk for that time, and the product 

 obtained by multiplying these percentages by the respective 

 number of pounds of milk furnished will give the number of 

 pounds of butter fat furnished. 



THE TEST APPLIED TO GATHERED CREAM BUTTER FACTORIES. 



When the Babcock test was first introduced, the butter facto- 

 ries of this State were nearly all buying cream by the inch and 

 paying a uniform price, regardless of its quality. The defects 

 and injustice of that system were, even then, realized at some 

 factories, and those in charge did not hesitate to say that a 

 change must be made or the business discontinued. For this 

 reason the Station recommended the use of the Babcock test, 

 believing that it offered a practicable and accurate method of 

 determining the actual butter value of cream. Nearly all of the 

 creameries in the State have adopted this system and are paying 

 for cream on the basis of the butter fat it contains. 



Causes which affect the quality of cream. Cream for butter 

 making is only valuable in proportion to the amount of butter 

 fat it contains, and there are many factors in raising cream 

 by the gravity process which have a decided influence on its 



