PEEFACB. 



THE object of this work is to provide dairy chemists 

 with a guide for the chemical control of dairy operations, 

 the assumption being that a knowledge of dairying is 

 already possessed ; and public analysts, medical officers, 

 dairy farmers, and Students with a practically useful 

 manual. 



The plan adopted is (1) to describe the chemical pro- 

 perties of the constituents of milk; (2) to make use of 

 these properties in the practical analysis of the various 

 milks and milk products; and (3) to apply analytical 

 methods to the control of dairy operations. 



Tn carrying out this work the author would especially 

 notice that its value may be largely attributed to two 

 factors. The first is that Dr. Paul Vieth (now Professor 

 in and Director of the Dairy Institute at Hameln) during 

 his twelve years occupation as Analyst to the Aylesbury 

 Dairy Company, accumulated a large number of obser- 

 vations, which, as he remarked, contained very little 

 theory, but a good deal of fact. This valuable material 

 was handed over to me as his successor, and has been 

 made full use of in this work. The second factor is that 

 the author owes much of his training as a dairy chemist 

 to Mr. Otto Hehner, who enjoys so high a reputation in 

 connection with butter analysis. 



It may also be stated that Mr. L. K. Boseley has kindly 

 read the Section on the Analytical Characters of Sterilised 

 Milk, that Mr. F. R. O'Shaughnessy has revised the mathe- 

 matical portions of the book, and that Mr. A. W. Stokes has 

 supplied the information respecting those methods which 

 bear his name. 



June, 1899. 



