THE CHARACTER OF THE FLAGEIvLA ON THE BA- 

 CIIvIvUS CHOIvER^ SUIS (SALMON AND SMITH), 

 BACIIvI^US COLI COMMUNIS (ESCHERICH), AND 

 THE BACII.LUS TYPHI ABDOMINAI.IS (EBERTH). 



By VERANUS ALVA MOORE. 



Recent studj' of the morphology of bacteria has demon- 

 strated the fact which Ehrenberg had foretold, that the motile 

 forms are possessed of flagella. The further prophecy that in 

 these minute hair-like appendages would be found vested the 

 power of locomotion, was partially fulfilled as early as 1875 

 by Dallinger and Drysdale, who saw these filaments con- 

 stantly lashing on a living, moving germ {Bacterium termo). 

 More recently Straus has made similar observations on several 

 species of bacteria. Colin, in 1872, and Koch, in 1877, 

 stained the flagella on a few of the larger saprophytic bacte- 

 ria, but the methods which they employed were so defective 

 that for more than a decade no further knowledge was gained 

 concerning the character or existence of these minute fila- 

 ments. The recent development of staining methods by 

 which the flagella can be demonstrated on all the motile 

 bacteria, is therefore of considerable importance, in opening 

 before us a hitherto unexplored field in the study of the mor- 

 phology of an exceedingly large and prominent class of the 

 Schizomycetes. 



Although considerable attention has been given to the 

 character of the flagella, the greater part of the work which 

 has been done on this subject has been directed to the devel- 

 opment of methods for their demonstration rather than to the 

 filaments themselves. As a natural result of this, our present 

 knowledge of the flagella is exceedingly fragmentary, and the 

 few statements concerning them are, in some instances, espe- 

 cially with the typhoid and coli bacteria, contradictory. The 



