DESCRIPTION OF CAUSATIVE ORGANISM 



Classification 



Bacterium salmonicida is classified as follows according to Bergey' s 

 Manual of Determinative Bacteriology (Breed et al. 1948). 



Kingdom Plant 



Phylum Thallophyta 



Class Schizomycetes Nageli 



Plants of this Class are typically unicellular. The cells are 

 usually small, sometimes ultramicroscopic, and frequently motile. They 

 lack a definitely organized nucleus. Individual cells may be spherical^ 

 or straight, curved, or spiral rods. 



Order I. Eubacteriales Buchanan 



Organisms of this Order are rigid. The cells occur singly, in 

 chains, or in masses. They are neither branching or nycelial in character, 

 nor arranged in filaments. They are not acidfast and motility when 

 present is by means of flagella. 



Suborder I. Eubac teriineae 



Organisms of this suborder do not possess photosynthetic pigments 

 and do not contain free sulphur. They are not attached by a stalk and 

 do not deposit ferric hydroxide. 



Family XII. Bacteriaceae Cohn 

 Genus and Species 

 Bacterium salmonicida Lehmann and Neumann 



Morphology and Staining 



Bacterium salmonicida is in general a short cylindrical organism 

 (Bmnerich and Weibel 1894. Plehn 1924., Williamson 1928, Duff and 

 Stewart 1933 )j> nonmotile and non-spore-forming (Emmerich and Weibel 

 1894;, Duff and Stewart 1933 ), with a tendency toward pleomorphism (Marsh 

 1902,, 1903i Arkwright 1912, Mettam 1914). It often occurs in pairs. 

 Williamson (1928) gives its dimensions as 1 to 4 /i in length ty 0.8 to 

 1 ;i in width but smaller and larger forms have been reported (Marsh 1903). 



