PREFACE 



DURING a connection of thirteen years with the Department of 

 Hygiene and Bacteriology of the University of Chicago, the author 

 evolved a course entitled "The Sanitary Aspect of Milk Supplies." 

 This course included laboratory work in which the student was 

 made familiar with the most important methods for carrying out 

 sanitary milk examinations. Parallel with this work a series of 

 lectures was given covering the physical and chemical proper- 

 ties of milk; the biology of milk, including bacteriology; and 

 methods of producing, handling, and distributing milk. The 

 material for these lectures was gathered from books and a large 

 number of original articles. Thus the foundation for the present 

 book was laid. 



The author does not claim that the subject has been exhaus- 

 tively treated. It is quite probable that some of the many mono- 

 graphs have been overlooked, and suggestions from authors of 

 the same will be received with gratitude. A book on milk which 

 would'cover the subject to the minutest detail would be in the na- 

 ture of an encyclopedia and would suffer in interest for the reader. 

 However, those interested in the milk problem, whether phys- 

 icians, sanitarians, students, or producers, will find that nearly all 

 the questions occurring to them have been touched upon, and for 

 the benefit of those who wish to follow up any particular avenue 

 in this vast subject a bibliography has been appended to each 

 chapter. This bibliography is sufficiently complete to serve as a 

 starting-point for further study. 



I have been aided in the preparation of this book by several 

 of my friends whose kindness it is a pleasant duty to acknowledge. 

 I am chiefly under obligations to Doctor Isaac A. Abt and Doctor 

 A. Levinson, who are authors of the chapter on "Milk and its 

 Relation to Infant Feeding." Doctor Henry L. Coit had kindly 

 consented to critically read the chapter on "Certified Milk," 

 but his lamented demise rendered the fulfilment of this promise 

 impossible. Professor A. J. Carlson made some pertinent criti- 

 cisms on the "Physiology of Lactation." 



My thanks are due to Professors Edwin O. Jordan and Norman 

 MacLeod Harris for valuable suggestions, and to Doctor Mary 

 Hefferan for critically reading the first manuscript. 



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