PREFACE TO FIRST EDITION. 



The present volume is intended for the use of dairy students, 

 factory operators, daymen, food chemists, and others inter- 

 ested in the testing or analysis of milk and its products. The 

 subject has been largely treated in a popular manner; accuracy 

 and clearness of statement, and systematic arrangement of the 

 subject matter have, however, been constantly kept in mind. 

 The aim has been to make the presentation intelligible to 

 students with no further training than a common-school educa- 

 tion, but their work will naturally be greatly lightened by the 

 aid of an able teacher. 



Complete directions for making tests of milk and other dairy 

 products are given ; difficulties which the beginner may meet 

 with are considered in detail, and suggestions offered for avoid- 

 ing them. It is expected that a factory operator or practical 

 dairyman, by exercising common sense and ordinary care, can 

 obtain sufficient knowledge of the subject through a study of 

 the various chapters of this book to make tests of milk, cream, 

 etc., even if he has had no previous experience in this line. 



For the benefit of advanced dairy students who are some- 

 what familiar with chemistry and chemical operations, Chapter 

 XIV has been added giving detailed instruction for the com- 

 plete chemical analysis of milk and other dairy products. The 

 detection of preservatives and of artificial butter or filled cheese 

 has also been treated in this connection. 



As the subject of milk testing is intimately connected with 

 the payment for the milk delivered at butter- and cheese fac- 

 tories, and with factory dividends, a chapter has been devoted 

 to a discussion of the various systems of factory book-keeping, 

 and tables greatly facilitating the work of the factory secretary 

 or book-keeper have been prepared and are included in the 

 Appendix. 



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