VI PREFACE TO THE THIRD EDITION 



application of methods of carrying out these important Public Health 

 questions has been added. 



In the chapter on " Immunity" a modification of Emery's technic 

 for the Wassermann test has been incorporated the use of Noguchi's 

 reagents with Emery's technic. The subject matter of the sections on 

 vaccines and anaphylaxis has been extensively revised. 



E. R. S. 



