Indole is not produced (Marsh 1903, Arkwright 1912, Mettam 1914, 

 Williamson 1928, Furunculosis Committee 1930, Duncan 1932, Duff and 

 Stewart 1933). 



Gi-ovrth occurs in peptone water (Marsh 1903, Arkwright 1912, 

 Williamson 1928), Marsh (1903) stated that growth resembled that in 

 broth but proceeded more slowly. Arkwright (1912) claimed that pigment 

 was produced more readily than in broth. 



Agglutination of B. salmonicida wj.th Fish Antisera 



Although Arkwright (1912) was unsuccessful. Duff (19A2) while 

 making a stud;^' of the oral immunization of trout obtained good results. 

 The antigen was suspended in 0,05 percent sodium chloride solution 

 instead of the common 0.85 percent. Incubation was carried out for U 

 hours at 37° C, followed by ice-box storage overnight. Preliminary 

 tests with immune rabbit-sera specific for B. salmonicida showed the 

 most sensitive bacterial suspension to consist of a Z^8-ho^n' agar growth 

 washed off with O0O5 percent saline solution. The suspension was not 

 killed and vras diluted to No. 4- McFarland turbidity standard for use. 

 Duff (1942) found that if kept in the cold the antigen is sensitive up 

 to 43 hours, after which sensitivity decreases. Blood was obtained 

 from trout by heart-puncture. A smiall quantity of heparin injected 

 directly into the heart was found necessary to prevent clotting in the 

 fine needles. His results are shown in table 6. 



B, salmonicida Complement Fixation 



Blake and Anderson (1930) submitted 82 strains of B. salmonicida 

 to the complement fixation test including 60 isolated from fish in 

 England and Scotland, and 22 received from other countries (Austria, 

 Germariy, Irish Free State, United States). All gave strongly positive 

 reactions. Twenty-one organisms other than B. salmonicida, isolated 

 from water, gave consistently negative results. Among these was an 

 organism which resembled B, salmonicida in pigment production. 



Variability of B. salmo nicida 



Biological characters 



The Furunculosis Committee (1933, 1935) found that B, salinonicida 

 shewed great unifoiTnity in its biological characters and that variability 

 was negligible. However, Duff (193?) found that by culturing B. 

 salmonicida in special media (phenol broth and lithiiun cliloride broth) 

 variants arose, with distinct morphological and colony characters. This 

 aspect of the study of B. salm-oni cida is dealt iTith separately in the next 

 section under "Dissociation". The conclusions of the Furunculosis 

 Committee (1933, 1935) witn respect to biological uniformaty in B. 



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