No. 4.] MILK AND CREAM. 363 



purchasers should therefore purchase a machine with a manu- 

 facturer's guarantee of efficiency. So far as the writer is 

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

 equal, thai separator is best that will skim the cleanest at the 

 lowest temperature, and with the least number of revolutions 

 per minute" with the least amount of power. The two sepa- 

 rators in most general use in New England are the De Laval 

 and the Improved United States. The Sharpies separator is 

 also used to some extent. Both the De Laval and the Im- 

 proved United States skim very close. The De Laval re- 

 quires rather less power to run than many machines. As is 

 well known, there are both hand and power separators. The 

 writer is not particularly inclined 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 convenient. 

 The separator aids naturally in removing impurities from the 

 milk, and milk is often run through the separator for this 

 purpose alone, and then remixed. These impurities form in 

 what is known as the separator 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 keej) 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 ordinary skim-milk, be- 

 cause of the more thorough removal of fat. The writer 

 believes the separator to be the most economical method of 

 securing milk fat, especially when the producer has a dairy 

 of fifteen or more cows. 



Pasteurization of Milk and Cream. 

 By pasteurization is meant the heating of milk or cream 

 up to a temperature of 155° F., holding it at that tempera- 

 ture 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 suggested 

 the idea for the purpose of increasing the keeping of beer 

 and wine. 



