Moore. — Study of Trout Diseases. 83 



Mr. Hare: Is there any connection at all between octomitiasis and 

 gill trouble? At the Manchester station the brook trout have for years 

 had an infection of the gills, and it seems they have never been able to solve 

 that problem. Under the glass they show no parasitic growth what- 

 ever. I am just wondering whether Octomitus would cause that trouble 

 at Manchester. 



Dr. Moore : Since I have found the organism in the blood it has 

 seemed possible that various parts of the fish should show pathologic 

 conditions. Before my attention came to be drawn to the study of 

 octomitiasis at the Bath hatchery, where no doubt it had been endemic 

 for yeai's, the mortality had been ascribed to "gill trouble," because as 

 death ensued the fish seemed to exhibit symptoms of suffocation. It 

 has seemed to me that the gill symptom was due rather to mechanical 

 causes. As the fish become less active during the progress of the dis- 

 ease various matters passing through the troughs in the water — algae 

 debris, food particles, etc. — m.ay easily clog the gills and cause the 

 feverish action so noticeable. There is room for further stvidy of this 

 phase of the question. Fish afflicted v/ith octomitiasis will, under cer- 

 tain conditions, develop a red spot or congested area of the blood 

 noticeable beneath the skin, on the fin or the belly, in the eye and 

 other parts. Very minute congested areas are also found in the gill 

 tissue. These seem to be manifestations of the disease. 



Mr. Titcomb: The so-called red spot disease, which has occurred 

 at Long Island, is not attributable to Octomitus? 



Dr. Moore: The red spot which occured at Long Island in 1898 

 and 1904 is not the red spot to which I have referred. The Long Is- 

 land trouble was associated with an open sore and was similar to furun- 

 culosis. 



Mr. Fearnow: As I understand it, the disease was introduced from 

 the brown trout. The brown trout is what we might term a more highly 

 cultivated fish than the brook trout or rainbow trout. Is it not possible 

 that this disease is one of the effects of a high degree of civilization in 

 fishes? 



Dr. Moore: It seems probable, in the light of observation and his- 

 tory that the disease has been introduced. I think really the brook 

 trout culture antedates brown trout culture. 



Mr. Fearnow: Is there any preventive for this disease, or any 

 known method of treatment? 



Dr. Moore: The only preventive that seems at all practicable at 

 present is a careful regard for prophylactic measures. In an infectious 

 disease of this kind, thorough sterilization methods are certainly neces- 

 sary in keeping the disease under control. Attention must be given to cer- 

 tain details, such as the avoidance of the use of utensils, brushes, feathers 

 etc., the second season, since they may harbor the resistant spores. 



Mr. Titcomb: Would it be advisable, in the case of fingerlings at 

 any given plant, to divide that plant into sections and use separate 

 brushes for each lot of progeny reared through the season? 



