90 American Fisheries Society. 



either, but, when I have been shown a bug, I can recognize him. You 

 cannot mistake Octomitus after seeing him once. 



We have had some rather interesting experiences in connection with 

 Bacterium truttae. We tried changes of food and the benefit has been 

 so great that, on examining the brook trout this year, we found no traces 

 of this organism. Whether relief is only temporary, of course, we do not 

 know. With regard to furunculosis, we had last year about 2000 brown 

 trout breeders in a pond that would run anywhere from 10 to 16 inches 

 long. A warm spell came on and we changed the fish from one pond to 

 another, expecting the water temperature to drop. Instead of that it 

 rose and furunculosis appeared on about one hundred of the fish, whereas 

 in a pond where no change was made the fish exhibited no symptoms of 

 the disease. I believe the way to get at this trouble is based upon three 

 factors, namely : the study of the temperature of the water and its effects, 

 the study of fish foods, and the building up of resistant strains. There 

 are many instances in which a very slight change in temperature has 

 a marked effect. It has been our experience that Bacterium truttae is 

 never very bad after the fish attain the age of eight months and there are 

 very few symptoms of furunculosis after they attain the age of 12 or 18 

 months. In our plant we have at the present time, roughly speaking, 

 150,000 fish running from 4 to 12 inches long. There are probably only 

 about a hundred fish now afflicted with furunculosis. 



Our ponds are so built that we can clean everything out and the 

 oftener we clean the ponds the less trovible we have. Cleanliness helps 

 a great deal in connection with Gyrodactyliasis. It also helps in the case 

 of furunculosis, but I cannot see that it means much so far as Octomiti- 

 asis is concerned. The fish culturist needs the scientist to check him up. 

 We have been employing Dr. Embody for the last five or six years. He 

 is much too modest to tell about the things he has observed, but he has 

 certainly been a wonderful help to us. We run our plant in four distinct 

 sections, each having its own water supply, and we have a man who looks 

 after each section. Acting on Dr. Moore's suggestion, we keep the 

 brushes separate ; we have determined to do that even if we have to put 

 a tag on the man and on the brush too. We find that it helps a great 

 deal. Another thing that helps is to be able to turn on a big flow of 

 water. The man in charge of these operations says, and I will quote 

 him exactly : "John, turn on a hell of a flow of water." 



Mr. John P. Woods: On the assumption that this disease is the 

 result of a foreign invasion, I would like to ask Dr. Moore whence it 

 came? 



Dr. Moore: It is impossible to answer positively. The brown trout 

 was introduced into this country from Germany in 1883. My theory is 

 that the disease may have been introduced through the importation of 

 eggs at that time. A hundred thousand brown trout eggs were sent to 

 Mr. Fred Mather, Superintendent of the hatchery at Cold Spring Harbor, 

 L. I., as a present from his friend, Mr. Von Behr, President of the Ger- 

 man Fisherei Association. According to the records, some of these eggs 



