In the tissues of salmon and trout , . . . 28 



Technique in isolation and demonstration 28 



Occurrence 28 



Specificity 29 



lypes 30 



Technique in isolation and demonstration 30 



Occurrence 30 



Origin 30 



Patholcgj'- 31 



Pathogenesis 36 



Determining factors 36 



Susceptibility of various fish to the disease in nature ...... 36 



The Salmonidae 36 



Variation among species and individuals 36 



Influence of age 38 



Other fish 39 



Recovery from the disease ^0 



Sources of infection and methods of spread of disease 40 



Spread of disease by rrater and food 40 



Carriers 40 



Occurrence 41 



Significance and nature 42 



Stocking in relation to the disease, 43 



Migratory Salmonidae as a source 43 



Other sources 45 



Factors favoring the prevalence of the disease 45 



Water temperature and floods 45 



Water pollution 47 



Lack of oi^gen 48 



Other factors 48 



Course of infection set up by diseased fish TO-th healthy- 

 contacts 49 



Diagnosis 49 



Technique of bacteriological examination (Furunculosis 



Committee 1930 49 



Heart blood 50 



Kidney 50 



Comparison with ulcer disease 52 



Pathology 56 



Control 58 



Prevention 59 



In hatcheries 59 



Care of ponds and utensils 59 



Handling of eggs 60 



Care of fish — immunization and selective breeders 63 



In nature 65 



Treatment 65 



The best drug 65 



Toxicity and tissue levels of sulfonamides in. fish 66 



Dosage, duration of treatment, and final recommendations .... 68 



Summary 70 



Acknowledgments 72 



References 72 



