MILK AND MILK PRODUCE ^ 389 



for butter fat. Good milkers are not more expensive to Iceep than 

 bad ; but the difiference of their yield may range between 1000 and 

 300 gallons, or less, a year. Unless the yield is recorded, the owner 

 may be annually losing money by several animals in his herd. 

 Similarly, the percentage of butter fat is of the utmost importance 

 both to the milk-seller and the butter-maker. Without occasional 

 tests, owners do not know which of their animals are lowering the 

 average of the herd, and to what extent. On the Continent, it is not 

 uncommon for the dairy-farmers of a district to combine and 

 contribute to the employment of a man who records and tests the 

 yields of milk at so much an animal. Similar associations have 

 been formed m Scotland for the same purpose, and County Educa- 

 tion Committees in England might well include this object among 

 the items of their expenditure. Such records are in other respects 

 valuable. Nothing is more hereditary than milking quahty. 

 Strains of milkers, whose pedigrees were based on records of their 

 performances, must command their price. In Denmark herd- 

 books founded on this principle have been already adopted with 

 success. In England the formation of the Dairy Shorthorn Associa- 

 tion (1905) marked the establishment of a practice which is beginning 

 to spread. Such milking herds as those of Lord Rothschild, or of 

 Messrs. Evens, Hobbs, or Watney, are already famous. 



In all the processes of dealing with milk, scientific principles and 

 mechanical aids have made triumphant progress. Fifty years ago, 

 in every stage from the churn, butter was made up and prepared 

 for market by hand ; wooden utensils were in common use ; 

 separators were unknown ; thermometers were rarely employed. 

 The value of the butter largely depended on the personal element 

 in the maker. Uniform quahty and condition were impossible ; 

 variety of both was the rule ; in winter months a regular supply 

 was difficult. It was not perhaps surprising that wholesale buyers 

 preferred the foreign products, on the uniformity of which they 

 could depend. At the present day the personal element, though 

 still all-important in the trade with private customers, is largely dis- 

 counted by the adoption of scientific rules and the use of mechanical 

 apphances. The sep arator has produced the greatest revolution 

 in dairy managem ent, and ranks with. the. reaper and binder as 

 one of the chief novelties of the period. The principle of the 

 centrifuge, invented in 1867 for separating hquids from such sub- 

 stances as paint, was applied to milk about 1879. It thus became 



