are almost a necessity before organisms can be seen in the liver. Plebr: 



(1911) found that bacterial clumps were not as plentiful in the liver as 



in the kidney. She also found that the stellate cells of v. Kupffer 

 were actively phagocytic. 



There maj'" be marked congestion of blood vessels of the abdominal 

 cavity (Davis 1946) accompanied by petechial hemorrhages in the 

 peritoneum, ejq^ecially in the region of the swim bladder (Plehn 1911 )• 

 The lining of the intestine and the pyloric region of the stomach may 

 be inflamed, and there is often a discharge of blood and mucus from the 

 vent. Plehn (1911) found that the mucosa of the stomach could be torn 

 away from the submucosa mth great ease. Congestion of the intestine is 

 also common (Bouville 1907). 



Congestion of the gills may also accompany any of the above 

 symptoms (Davis 194-6). 



Table 9 shcms the frequency of lesions found by Duff and Stevfart 

 (1933) during an epizootic in British Columbia. Note that in all cases 

 there were muscle lesions and necrosis of the kidney. The Furunculosis 

 Committee (1930) points out that the distribution of lesions is extrem.ely 

 variable from specimen to specimen. However, in diseased fish, the 

 organism is most frequently demonstrated in heart blood and kidney. The 

 Furunculosis Comnittee (1933) found that B. salmonicida was recovered 

 less frequently from the intestine than from the kidney or blood. 



As already indicated there is practically no leucocytic 

 infiltration iidth furunculosis. Blake (Fur-onculosis Committee 1935) 

 in a special study of this aspect of the disease found that films of 

 blood of infected fish showed the presence of free bacteria in 

 considerable numbers vrith relatively little phagocytosis. The first 

 stages of an inflammatory reaction appeared to take place around the 

 site of inoculation, especially if this was intraperitoneal. Vessels 

 became dilated, plasma escaping into the surrounding tissues, but there 

 was no definite migration of leucocytes and those present were seen to 

 be degenerate. A certain amount of hemolysis occurred at an early stage 

 of blood infection, and the progress of this was readily dem.onstrabed by 

 the observation of free nuclei of erythrocytes in blood films. A 

 pronounced effect on the capillary blood vessels was manifested by the 

 considerable degree of edema and the frequent occurrence of petechia] 

 hemorrhages. 



Although in furunculosis engulf ment of the causative organism 

 ty wandering mesodermal cells is not an outstanding feature, this is 

 not true vdth all general infections of fish. Vasculai- reactions were 

 found by Blake (1935) to be much more marked in cases of infection by 

 vibrj.os, Ac hromcbacter types, and Pseudomona s fluorescens than by B. 

 salmon ic Ida . Phagocytosis vras verj' active by mononuclear cells 

 (probably endothelial in origin), even mere than by pol^itiorphs. When 



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