vi PREFACE 



reliable indications as to the progress of many cases of 

 infection of the digestive tract. 



Without the cooperation of my associates I could not 

 have obtained the data given in this volume. I am under 

 especial obligations to Dr. Helen Baldwin, Miss M. L. 

 Foster, Dr. A. J. Wakeman, Mr. H. C. Ward, and Dr. 

 William R. Williams for the efficient help which they 

 have in various directions given me. 



DECEMBER 1, 1906. 



