36 



skim to .1 of 1 per cent butter fat or less. This may be illustrated from 

 the following table : — 



Per cent Fat in 

 Machines. Skim-milk. 



Accumulator, 11 



Alexandria Juuibo, 22 



Columbia, 12 



Danish Weston, 08 



De Laval, 09 



Sharpies, '.AG 



United States, 12 



Victoria, 16 



While the majority of separators can be made to do perfect work, 

 there ai'e variations in different machines of the same grade and manu- 

 facture, and these differences can only be detected by an actual exami- 

 nation ot the skim-milk. The purchaser should therefore purchase a 

 machine with a manufacturer's guarantee of efficiency. So far as the 

 writer is aware, there is no best separator. " Other things being equal, 

 that separator is best that will skim the cleanest at the lowest tcmj)era- 

 ture, and with the least number of revolutions per mimite,^'' with the least 

 amount of power. The two separators in most general use in New 

 England are the De Laval and the Improved United States. The Sharp- 

 ies separator is also used to some extent. Both the De Laval and the 

 Improved United States skim very close. The De Laval requires rather 

 less power to run than many machines. As is well known, there are 

 both hand and power separators. The writer is not particularly in- 

 clined towards hand machines, because of the labor involved in turning 

 and would advise those who are purchasing to secure some sort of 

 power, either horse, water motor, gas engine, or steam if more con- 

 venient. The separator aids naturally in removing iminirities from the 

 milk, and milk is often run through the separator fortius purposes alone, 

 and then remixed. These impurities form in what is known as the sep- 

 arator slime. The advantages of the separator, briefly stated, are that 

 the milk can be skimmed as soon as drawn, rapidity of skimming, clean 

 skimming, with thin or thick cream, as desired. Separator skim-milk 

 will not keep sweet as long as skim -milk obtained by the deep-setting 

 process, unless it is cooled and kept at a low temperature at once after 

 coming from the separator. It naturally looks rather thinner than ordi- 

 nary skim-milk, because of the more thorough removal of fat. The 

 writer believes the separator to be the most economical method of secur- 

 ing milk fat, especially when the producer has a dairy of fifteen or more 

 cows. 



Pasteuhization of Milk and Cream. 



By pasteurization is meant the heating of milk or cream up to a tem- 

 perature of 155° F., holding it at that temperature from twenty to thirty 

 minutes, and then cooling it rapidly to 50° F. The term pasteurization 

 is derived from the celebrated French chemist, Pasteur, who first sug- 

 gested the idea for the purpose of increasing the keeping of beer and 

 wine. 



The object of holding the milk or cream at this temperature is to des- 

 troy or render harmless for a considerable time the various bacteria 



