PREFACE TO TWENTY-SECOND EDITION. 



Each year that passes brings some valuable contributions to our 

 knowledge of the subjects treated in this book and a frequent re- 

 vision of it is therefore desirable. The present edition contains 

 descriptions of methods and apparatus that have stood the test of 

 actual use during the past few years; the new information pub- 

 lished since the last revision of the book has been carefully sifted, 

 and what was deemed of sufficient importance has been incorpo- 

 rated in such detail as the scope of the book permitted; many 

 changes and additions suggested by the experience of the authors 

 have also been introduced. The book has, in brief, been subjected 

 to a renewed critical examination and careful revision. 



The general adoption of the book as a text or reference book in 

 American dairy schools, as well as the favorable reception which it 

 has been accorded by the dairy public in general, will, it is hoped, 

 be further justified by the present revision. Acknowledgment is 

 due to the following parties for loan of electrotypes, viz. : Cream- 

 ery Pkg. Mfg. Co., Chicago, 111.; Vermont Farm Machine Co., 

 Bellows Falls, Vt.; D. H. Burrell & Co., Little Falls, N. Y.; Henry 

 Tromner, Philadelphia, Pa.; Torsion Balance Co., New York City, 

 and Marschall Dairy Laboratory, Madison, Wis. 



Madison, Wis., Oct. 1, 1913. 



