PEEFACE. 



The revolution in dairy practice brought about 

 by the introduction of the centrifugal cream sepa- 

 rator and the Babcoek test for fat and by a more 

 definite knowledge regarding the various fermenta- 

 tions that so greatl}' influence milk and the manu- 

 facture of its products, has seemed to demand the 

 publication of a small handbook that shall give 

 to the dairyman, and particularly to the dairy 

 student, in simple, concise form, the principles un- 

 derlying modern dairy practice. In attempting to 

 meet this demand, I have had largely in view the 

 needs of my own students, while still keeping in 

 mind the general dairy reader. 



In the colhition of the information, where so 

 many points are still unsettled, it is of course dif- 

 ficult in all cases to distinguish fact from conjec- 

 ture. The aim has been at all times to give 

 the present state of knowledge as supported by 

 the weight of evidence and the opinions of those 

 whose authority is highest. In how far this has 

 been successful time alone can tell. It would be 



(vii) 



