Moore. — Study of Trout Diseases. 81 



the production of resistant spores (VIT and VIIi). Such 

 spores as indicated above pass from the intestinal tract and 

 function in the transmission of the organism from fish to fish. 

 The final products resulting- from the germination of the spores 

 (VIII, IX and Villi, IXi), presumably in the stomach of the 

 new host, carry the cycle to the point of beginning. 



To summarize briefly the observations of the year incline 

 to the belief : 



1. That the organism, Octomitus, is not indigenous to 

 our native brook trout, but was introduced from Europe. 



2. That infection extends to wild waters. 



3. That the main features in the life history of the or- 

 ganism indicate a complete cycle of events within the body 

 of the fish, with transmission of the germ from fish to fish by 

 means of a resistant spore. 



Discussion. 



President Leach: Dr. Moore has dealt very ably with the studies 

 in progTess. Octomitiasis is a disease which has also given the Bureau 

 of Fisheries no httle concern, and Dr. Davis, our pathologist, has also 

 made some interesting studies in this connection. I am sure that many 

 of you will wish to take part in the discussion. 



Dr. Osburn: I wish to congratulate Dr. Moore upon her presenta- 

 tion of this valuable paper and to commend her for the persistence with 

 which she has carried out this very detailed work. An infinite amount 

 of patience is necessary to the pursuance of studies of this kind. One 

 point upon which I am not quite clear is just what is the cause of death? 

 Is there any loss of blood from these lesions, or is death due to toxic 

 action of some sort? 



Dr. Moore: There is loss of blood. In severe infection the epithe- 

 lial cells slough off and this must permit a more or less continuous loss 

 of blood from capillaries that are situated near them. Extrusions of 

 intestinal content show the presence of blood corpuscles, in greater or 

 lesser amounts varying with the severity of the disease, and I think it is 

 safe to say that this is an attending cause of death. 



Dr.Osburn: How long does this condition last? 



Dr. Moore: It appears to vary considerably. At some hatcheries 

 the disease manifests epidemic conditions early in the season, at others 

 later. An epidemic during which practically all fish become infected 

 may be in progress several weeks. 



Dr. Osburn: It might be a wasting disease as a result of loss of 

 blood might it not? 



Dr. Moore: Mortality is highest among the stunted and emaciated 

 fingerlings and thei-e is every reason to suppose they have had the dis- 

 ease longest. They have large heads and thin wiry bodies, they carry 

 heavy infections of the organism and have been observed to take little or 

 no food. 



