X PREFACK 



experience and advice; more than three hundred 

 farmers and dairymen have kindly permitted me to 

 visit their premises and helped me in many other 

 ways; and, not less important, nmnerous mothers have 

 given me their confidence and most loyal cooperation. 

 To all of these I have tendered my thanks personally, 

 and it remains only for me to make this public ac- 

 knowledgment of valuable assistance freely and gen- 

 erously given. 



To some of my friends I am so deeply indebted for 

 special assistance that a word of acknowledgment, 

 other than that given above, seems necessary. I 

 desire, therefore, to take this opportunity of specially 

 thanking the following gentlemen : Dr. Henry Dwight 

 Chapin, Professor of Diseases of Children at the New 

 York Post-Graduate Hospital; Professor R. A. 

 Pearson, of Cornell University; Dr. George W. Goler, 

 Health Officer, Rochester, N.Y.; Dr. Thomas Dar- 

 lington, Health Commissioner, New York City; 

 Dr. W. H. Park and William E. Burton, of the Health 

 Department, New York City; Dr. E. F. Brush, of 

 Mount Vernon, N.Y. ; Dr. John B. Huber, of New York 

 City; Dr. Arthur Greene, of the Straus Laboratories, 

 New York City; Professor Gustav Bang, of Copen- 

 hagen; Mr. Lewis W. Hine, of Yonkers, N.Y., and 

 Mr. William Wirt Mills, of the New York Evening 

 Mail, who generously placed at my disposal a valuable 

 collection of papers and reports. 



YONKEBS, N.Y. J. S. 



