2 6 THE BUTTER INDUSTRY IN UNITED STATES [250 



the need for an accurate and simple test was also greatly 

 felt. It was necessary that the test be absolutely accurate, 

 because prosecutions would be based on the results of the 

 test if they should show adulteration or dilution. The pro- 

 cess had to be expeditious because inspectors were called 

 upon to make a great many tests. Prof. Edward W. Mar- 

 tin, of the School of Mines, Columbia University, was 

 employed as chemist by the first Dairy Commissioner of 

 New York State, and had charge of the force of milk in- 

 spectors. He devoted considerable time to the problem of 

 finding a suitable test. 1 



Practically everywhere creameries, cheese factories, and 

 condenseries now buy the milk on the basis of the fat test 

 and not by weight or bulk. This is, of course, only fair. 

 The U. S. Agricultural Experiment Stations have con- 

 ducted experiments the results of which show that the 

 percentage of fat in the milk of the different breeds of 

 dairy cows varies widely. The average yield of butter fat 

 of the Holstein cow is found to be 3.45 per cent; of the 

 Ayrshire cow, 3.85 per cent; of the Guernsey cow, 4.98 per 

 cent; and of the Jersey cow, 5.14 per cent. 2 It is to be 

 expected, of course, that the yield of fat of individual cows 

 would vary considerably from the average yield of a breed. 

 The fat content also varies considerably in a single cow at 

 different times during the period of lactation. The im- 

 portance of paying for milk on the basis of the fat test is 

 more apparent in butter-making than in cheese-making, be- 

 cause the number of pounds of butter that can be made 

 from the milk varies almost directly with the percentage of 

 fat in the milk. Viewing the problem, therefore, from the 

 side of the manufacturer, it is important that he pay a 



1 Vide, N. Y. State Dairy Commissioners' Report for 1885. 



2 Bulletin 156, Bureau of Animal Industry, U. S. Department of 

 Agriculture. 



