88 American Fisheries Society. 



Mr. Foster: An interesting case came up at Neosho last 

 spring when Dr. Davis was there. He had just returned from 

 Manchester station after examining the eifects of Octomitus. Hardly a 

 year previously we had received some yearling brook trout from the 

 Manchester station which no doubt had the disease at the time they were 

 brought to Neosho. These were examined by Dr. Davis as were other 

 trout at Neosho, and no trace of Octomitus was found. What the 

 condition was that eliminated it we do not know. 



One of the symptoms mentioned by Dr. Moore, the heading of the 

 fish to the side of the trough, is also a symptom of disintegration of the 

 kidneys with crystals, which condition we have had to deal with for a 

 couple of years. The crystals are very prominent and the disintegra- 

 tion is quite noticeable. That can be corrected, as has been found in 

 some hatcheries, I believe, by thinning the fish from the troughs at an 

 early age and placing them out of doors. We found that by doing that 

 the trouble did not occur, whereas we did have it where the fish were 

 held in the house. 



It would seem that there is some similarity between octomitiasis 

 and intestinal trouble in the human being in connection with which 

 the typhoid serum is administered, so that the measures employed in the 

 treatment of typhoid might apply in some degree to the treatment of 

 Octomitus. Of course, we can scarcely develop a serum for the 

 treatment of each individual fish, but some of the measures adopted 

 might be of use. 



Dr. Moore: That is an important observation regarding the elimi- 

 nation of Octomitus from presumably infected trout and is paralleled 

 more or less by a single observation of my own. Not long ago I visited 

 one of our hatchei'ies where in recent years it has been impossible to 

 carry adult brook trout very long in the ponds at the station. One adult 

 male brook trout, about 12 inches long survived. On examination 

 it was found not to be infected with Octomitus but by another species 

 of protozoan parasite, a sporidian. Such observations, however, must be 

 greatly extended in order to generalize from them the conditions 

 favoring immunity. 



The point raised by Dr. Osburn regarding the development of 

 immune strains seems a most practical and forward looking suggestion. 

 Dr. Embody has already started work along this line. From my obser- 

 vations at the Bath hatchery the trout fingerlings which survive do so 

 because they apparently acquire immunity. After the epidemic passes 

 the survivors attain a splendid growth and become remarkably fine fish 

 for planting. They are however "carriers" still. What happens after 

 planting in general is still a matter of conjecture. Some specific in- 

 stances of what happens near hatchery outfalls have been discussed in 

 my paper. 



Mr. Bullock: When our scientists took up the study of the cause 

 of malaria and found the organism, they not only recommended 

 prophylactic measures, but they found a medicine which was effica- 



