PREFACE TO FIRST EDITION. 



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

 factory operators, dairymen, food chemists, and others interested 

 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 sub- 

 ject 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 education, 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 givetn; 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 hei has had no previous experience in this line. 



For the benefit of advanced dairy students who are somewhat 

 familiar with chemistry and chemical operations, Chapter XIV 

 has been added giving detailed instructions for the complete 

 chemical analysis of milk and other dairy products. The detee- 

 tion 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 bookkeeper have beein prepared and are included in the 

 Appendix. 



Madison, Wis., October 1, 1897. 



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