94 American Fisheries Society. 



Chemicai, Analysis. 



Parts per miilion. 



Odor 1 vegetable 



Color trace 



Turbidity clear 



Nitrogen as free ammonia .028 



Nitrogen as albuminoid ammonia .016 



Nitrogen as nitrate trace 



Nitrogen as nitrate 



Oxygen consumed 



Chlorine 



Total hardness, soap method. 

 Alkalinity 



_ 1.40 



0.10 



7.00 



190.00 



__ 160.00 



Total solids in solution 224.00 



Discussion. 



Mr. C. O. Hayford, Hackettstown, N. J.: This paper of Dr. Moore's 

 is exceedingly interesting to me. I have often encountered the same trouble, 

 as the fish from every appearance had the same symptoms as described by 

 Dr. Moore. I lost this year, in a single night, from one pond, 1,700 brook 

 trout fingerlings. My scientific assistant, Mr. Foster, has made some progress 

 in investigations, but w^e have not the means and experience of getting at 

 this subject that Dr. Moore has. It may be interesting to know that when 

 we take the artificial food entirely away from affected fish and give them 

 their natural food, the mortality greatly diminishes. Our trouble generally 

 comes when the black birds make their first appearance. At first we were 

 inclined to believe they might be carriers of the trouble. Examinations of 

 cultures from the excrement, blood, etc., have been of no value thus far 

 We also found, as Dr. Moore stated, that the greatest mortality is among 

 the brook trout. We have very little trouble with the rainbows, and this 

 is the first year the brown trout contracted it to any extent. One interest- 

 ing point about the brown trout is that a little brown spot appears on top of 

 the head just back of the eyes. Soon after this spot becomes visible the 

 fish generally starts a spiral whirl along the sides of the ponds and is finally 

 carried against the overflow screen. We have a great many springs boiling 

 out of the ground that supply our hatchery. These springs vary in oxygen 

 from two and one-half to eleven parts per million. Carbon dioxide zero 

 to fourteen parts per million. Three years ago ponds carrying the highest 

 percentage of carbon dioxide gave us the most trouble. This year they gave 

 us the least. Therefore we can not at present attribute it to the carbon 

 dioxide. 



Mr. W. T. Foster, Easton, Pa.: I should like to ask Dr. Moore if 

 she occasionally found some of the infected trout turning a darker color, 

 with the gills light instead of reddish? 



Dr. Moore: Yes, I believe I can say that. I thought that might bt 

 attributable, however, to variation in the natural coloration; but I have 



