PREFACE ix 



hitherto unpublished photographs of the Streptococcus scarlatince ; 

 to Dr D. S. Davies of Bristol for the two graphic-method charts 

 illustrating milk-borne outbreaks ; to Mrs George Newman for the 

 water-colour drawings of cultures and the text illustrations drawn 

 from apparatus used by us ; and to various workers too numerous 

 to name, in England, France, Germany, and America, who have 

 responded to our requests for information. We are also under 

 obligation to the American Government and various State Boards 

 for many official reports. In conclusion, we desire to express our 

 appreciation of the unfailing courtesy and assistance of the 

 publisher. 



London, October 1903. 



a 2 



