BY R. GREIG SMITH. 607 



not infected by way of the alimentary canal, but by an accidental 

 wound or a bite from another fish. 



The organism was cultivated upon the usual media with the 

 view of determining its name or its allies, and the actual appear- 

 ances, etc., are here recorded for future guidance. 



Description of the Bacterium. 



Shape, etc. — It is a short rod with rounded ends. The size is 

 variable, ranging from 045 to 0-7 /x in breadth, and from 1*2 

 to 1'5 fx in length. Longer forms may occur. In the animal 

 tissues it has a distinct capsule. The organism stains feebly with 

 methylene-blue, better with thionin-blue, and strongly with carbol- 

 violet or carbol-f uchsin. With the latter stains many of the forms 

 appear more or less bent and vibrion-like. When stained with 

 thionin-blue, with dilute fuchsin, or with carbol-fuchsin, followed 

 by washing in alcohol, the younger organisms exhibit bipolar 

 staining; the older and longer organisms stain in three places, at 

 the poles and centrally. This latter appearance is probably 

 caused by two organisms whose ends are close together while 

 enclosed within a thin capsule. The cells are actively motile, the 

 motion being produced by a single terminal flagellum, whose length 

 varies from 1| to 3 times the length of the cell. The organism 

 does not appear to form spores. 



Gelatine plate. — In 24 hours, at 22° C, the organism forms in 

 the medium circular liquefied areas about 1 5 mm. in diameter. 

 The colony shows a white central point and a white marginal 

 ring. When magnified sixty-fold, there is seen an irregular 

 brownish -black granular centre, then a clear portion containing 

 large floating granular clumps, and finally similar large granules 

 clustered around the margins. The appearance is like a colony 

 of Vibrio cholera'. The edge of the colony is smooth. In 48 

 hours the colony widens to 5 mm., and the contents appear uni- 

 formly turbid. 



Gelatine stab.— The medium is liquefied along the line of 

 inoculation in 24 hours in a tubular manner, and an air-bubble 



