In ulcer disease the jaws and roof of the mouth are frequently attackedo 

 Fish (1934) was unable to demonstrate any bacteria in blood and internal 

 organs of fish with ulcer disease. He believes the causative agent 

 produces a toxin. Leucocytic infiltration is outstanding in ulcer 

 disease. Fungus on lesions of ulcer disease is rarer than in furunculosis. 



16. Control of furunculosis falls under two categories, prevention 

 and treatment. Hatcheries should be disinfected at least twice a year.„ 

 using a concentration of chlorine of 200 p.p.m. Utensils and workers' 

 hands should be cleaned regularly. All eggs should be disinfected with 

 either acriflavine (1§2000 for 20 minutes) or sulfo-merthiolate (ls7500 

 for at least 10 minutes). Immunization of trout is not parti cularjy 

 successful^ but the results of selective breeders are encouraging. 

 Prevention in nature amounts to stocking with healthy fish^ keeping 

 water levels up^, avoidance of pollution, and burying all dead fish 

 during an epizootic. 



17. The best drug in the treatment of furunculosis is sulfamerazine. 

 Tne order of toxicity of various sulfonamides iss sulfamerazine ^ 

 sulfamethazine, sulfadiazine,, and sulfathiazole^, which is least toxic 



and least satisfactory for treatment. Dosages and duration of treat,ment 

 and final recommendations are discussed. 



ACKNOWLEDGEMENTS 



In the preparation of a monograph, one is grateful for the 

 assistance given by numerous sources. I wish to express my appreciation 

 to Dr. S. F. Snieszko, Kearneysville, W. Va., whose encouragement and 

 interest was primarily responsible for the publishing of this paper. 



I also wish to thank the Williams and Wilkins Company, Baltimore, 

 Maryland for permission to reproduce the classification of Bacterium 

 salmonicida according to Bergey's Manual of Determinative Bacteriologyi 

 for permission to reproduce tables 2 and 4- in a modified form (table 6 

 in manuscript) from the Journal of Immunology UA% 87-94-, 1942| for 

 permission to refer considerably to material contained in the Joirrnal of 

 Bacteriology 34s 49-67, 1937 and 38s 91-100, 1939 and for permission to 

 reproduce in a modified form tables 2, 3 and 4 (tables 7, 8 and 9 in 

 manuscript) from the Journal of Bacteriology 38s 91-100, 1939. I am 

 also grateful to the Editor of the Journal of Bacteriology, Dr. J. R. 

 Porter for his permission to use material contained in that Journal. 



l|yr thanks are also extended to Dr. D. C. B. Duff of the University 

 of British Columbia for his permission to refer and use material from 

 work done by him on the viability, dissociation and serological 

 relationships of B. salmonicida , and on the pathology of, as well as 

 the oral immunization against, furunculosis in fish. Much of his 

 studies have been on aspects of B. salmonicida not covered by other 

 workers. A considerable proportion of the Section on 'Viability' of 



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