PREFACE Vll 



investigations and for the far-reaching influence of 

 the results of their work the agricultural experi- 

 ment stations of the states of Wisconsin and 

 of New York (Geneva). The results of these and of 

 other useful investigations are not now easily avail- 

 able, being scattered through many reports and 

 bulletins, most of which can be found only in large 

 libraries. One of the tasks proposed at the outset 

 in the preparation of this book was to digest this 

 large mass of valuable material and present the 

 results in systematic form, thus making it for the 

 first time readily available to all dairy students. An 

 exhaustive, detailed history of these investigations 

 would compel one to present some results and in- 

 terpretations which more accurate work has later 

 shown to be erroneous. Those for whose use this 

 book A has been prepared are more interested in 

 knowing what the status of our present knowledge 

 is than in studying the various details which have 

 preceded. The chief aim, therefore, has been to 

 digest and summarize the results of investigation 

 in such a way as to give what, in the light of our 

 present knowledge, we may now regard as the 

 probable facts and their proper interpretation. This 

 task is a somewhat discouraging one, because new 

 facts are being rapidly added to our knowledge 

 and, in consequence, what we may now hold as 

 true is quite likely to need modification in the near 

 future. 



The main portion of this book is devoted to 

 cheddar cheese for the obvious reason that this is 

 the kind most extensively made in America. A 

 few other kinds of cheese are briefly discussed, so 



