190 MODERN BUTTER MAKING. 



cate an excess of .2 per cent acidity. Thi.s can very 

 easily be accomplished by using the "Rapid Meth- 

 od" (par. 48), devised by Prof. B. H. Farrington, 

 who is at the head of the Universi'ty of Wisconsin 

 Dairy School. Anyone who is at all dextrous can 

 very rapidly select or grade milk as received at the 

 milk depot. The rapid method k- simple, accurate 

 and inexpensive, and is used with great success at 

 the Wisconsin Dairy School. 



Because the sweeter milk is selected for the mar- 

 ket it is possible that when a large percentage of the 

 milk shows more than .2 per cent acidity and is re- 

 jected, that the test of the milk sold may show a 

 rather low fat content. The reason of this is that 

 evening milk is usually richer in fat than morning 

 milk and it is usually the latter -which shows more 

 than .2 per cent acidity. According to Richmond 

 (Richmond*) the composition of milk varies greatly 

 in fat content. He says: "The average fat content 

 of morning milk was 3.52 per cent and of evening 

 milk 3.96 per cent in 15,910 samples." 



242, Variations in the test of individual cows and 

 herds. 



There is a difference in the average test of a herd 

 from year to year as well as in the test of individual 

 cows. The test of individual cows may vary con- 

 siderably from day to day as well as the total pro- 

 duction of fat per day. In order to make this vari- 

 ation more clear, the following table is given, which 

 shows the age of cows, the average per cent of fat 

 in milk and the range of variation in milk from indi- 

 vidual cows. 



* Richmond, H. D. Analyst, page 30, 1905. No. 355, paragraphs 325-329. 



