PREFACE 

 TO SECOND REVISED EDITION 



Five years have passed since this book was last re- 

 vised. During these few years, new demands have 

 arisen, and, in response, new methods of testing milk 

 and milk products have been developed, which 

 are in constant requirement and which should, 

 therefore, be readily available. Some idea of 

 the extent and direction of the activity in 

 these lines can be gathered from the number 

 and character of the changes introduced in the 

 present edition. Without going into details, it is 

 sufficient to say that four chapters, consisting .almost 

 entirely of new matter, have been added, and several 

 other chapters have been completely rewritten and en- 

 larged by incorporation of much .additional material, 

 while in only a few chapters has there been no appre- 

 ciable change. It has been desired to make the re- 

 vision sufficiently thorough to bring the subject mat- 

 ter fully up to date. 



L. L. VAN SLYKE. 



Geneva, N. Y., August, 1912, 



