pi-esumptive evidence, at least, suggests that there is a possible association 

 between feeding fish as food and this disease. 



Mb. N. R. Buller, Harrisburg, Pa.: The bacterial disease referred 

 to by Dr. Belding and Mr. Hayford is not new. Going back 30 years I 

 know of a hatchery in Pennsylvania where an epidemic of this kind 

 occurred. It is not always in high temperatures that the disease prevails, 

 for here the maximum in the ponds was only 50° F. Drastic action was 

 taken, every fish being killed and the ponds emptied and thoroughly steril- 

 ized. The hatchery is in operation today and since that time there has been 

 no trouble from the disease. I would hesitate to believe that this particular 

 disease can be transferred in the eggs, for the reason that we have hatched 

 many that came from stations where it was present, without any apparent 

 development of the disease. 



Mr. Leach : I never heard of the disease at our western stations 

 where we take eggs from wild fish. It has only occurred at such 

 stations as are supplied with eggs from commercial hatcheries, and I 

 thought possibly it was due to the lowering of the vitality of those fish. 



Mb. Carlos Avery, St. Paul, Minn. : I would like to know the opin- 

 ion of these scientific men as to whether fish from wild streams would not 

 be more liable to such diseases than healthy domesticated fishes, and 

 whether immunity might be built up in these domesticated fishes, the same 

 as in other animals? 



Db. G. C. Embody, Ithaca, N, Y. : At times during the last three 

 years I have been working with Mr. Hayford in an effort to develop in 

 trout a resistance to certain bacterial diseases. The results thus far are 

 very promising, but we believe it will take six years, at least, to bring them 

 to a point where we will be able to deduce any permanent conclusions. So 

 far our experiments indicate a practical explanation of what happened in 

 the case of the breeders at a certain hatchery. I am not sure that it was a 

 bacterial disease there, but it was some kind of disease, and the presumption 

 is that it was bacterial. At any rate the trout that were right below the 

 basin which was so badly infected, did not take the disease. I understand, 

 from what Dr. Belding said, that this disease rarely occurs in wild trout, 

 that he found very few cases among the wild trout. Is that true? 



Db. Belding: I have never found it in wild trout, but have cited it 

 in two pickerel from different ponds in Massachusetts. It has been reported 

 in wild salmon and trout in Ireland and in a number of rivers in Bavaria. 

 I also understand that it is present in wild fish in New York, New Jersey 

 and Pennsylvania and is especially prevalent in certain private preserves. 



Db. Embody: At any rate it is not so prevalent among wild fish as 

 among hatchery fish, and in my opinion it is distinctly a disease of domes- 

 tication. We have diseases of domestication in the history of our poultry 

 breeding. If you take wild jungle fowl, from which all of our poultry are 

 supposed to have come, and put them in a chicken coop and try to raise 

 them like ordinary chickens, I am sure you would not raise very many. 

 They are susceptible to the diseases of domestication. Our domestic poultry 

 are resistant to those diseases. It has taken hundreds of years to bring 

 that about through unconscious selection at a time when nothing was 

 known about selective breeding. Something is known about that now and 

 I believe we are justified in attempting to produce disease-resistant trout. 



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