The Character of the Flagella 363 



4. Until further facts are determined, the character of the 

 flagella will not furnish a means for specific differentia- 

 tion. The species and varieties must be determined by their 

 physiological and pathogenic properties while the genera may 

 be fixed by the character of the flagella. 



5. The proposition that the Bacillus typhi abdomi7ialis is a 

 modified form of Bacilhis coli communis caiuiot be justly 

 refuted on their morphological characters. The similarity in 

 the structure (as it is now understood) of these bacteria in- 

 creases the importance, from a difi'erential standpoint, of the 

 differences found to exist in their biological and etiological 

 manifestations. 



Washington, D. C, 

 July 31, 1S93. 



