Ward. — Fish Parasites and Parasitic Diseases 243 



Dr. Buan : In New York we have had to deal with a great variety 

 of diseases, due not always to bacteria and to larval worms — chiefly 

 though to these sources — as the causes of epidemics; and up to this 

 time wc have been unable to utilize to any very great extent the writ- 

 ings of the students of these forms of Protozoa, bacteria and worms, 

 which lie at the root of our troubles. There is only one book so far 

 which the practical fish culturist has been able to consult with any 

 great profit, and that is the little book by Dr. Hofer, which, of course, 

 every advanced student has in his library; and even Dr. Hofer has 

 not gone far enough with his studies. In fact, the Germans who have 

 been so patient in their researches have not gone far enough to lift 

 us out of the hole in which we are floundering. Of course, Dr. Ward 

 knows that better than any one else. 



What we have done in New York is this : We have begged the 

 special students to help us, and then have not waited for them to com- 

 plete their studies; but we have changed our water supply wherever 

 possible, because we realized that these troublesome little animals and 

 plants originate usually in filth due to sewage. At one of the stations 

 of the commission which was put out of business four or five years 

 ago, and had been out of business practically for a great many years 

 prior to that time, we cut out a beautiful little stream because it re- 

 ceived drainage from manure heaps and cesspools. It had brought on 

 what we know as the spot disease of the brook trout and the ulcer 

 disease of the brown trout. There did not seem to be anything helpful 

 in literature, and for that reason we cut out the stream entirely, sunk 

 some artesian wells, and fortunately found water at a depth of 19 or 

 20 feet. We bought smue good springs of which we controlled the 

 heads, and since that time the station has become rehabilitated; and 

 whereas it was difficult a few years ago to deliver to the people of 

 New York 200,000 or 300,000 brook trout fingerlings and fry, this year 

 the same station has been troubled to get rid of its surplus of brook 

 trout ; and the people who have received the fish have commented on 

 the fact that they are the finest brook trout they have ever seen. It 

 was a very simple process, of course, of a cure. The cause lies in a 

 little creek which flowed through the hatchery ground ; but we are 

 not using it now. The same thing was done at Cold Spring Harbor, 

 largely through the help of the Bureau of Fisheries. Messrs. Calkins 

 and Marsh went there and told us what lay at the root of the trouble. 

 and as they could not suggest a cure we changed the water supply 

 there and are now drawing artesian water through three pipes, which 

 furnish quite enough to run the hatchery. 



I do not believe that a case of spot disease of the brook trout or 

 ulcer disease of the brown trout has appeared at that hatchery for years. 

 If there is one, I have yet to learn of it. 



There is another very troublesome thing at the station in Constantia. 

 on Lake Oneida, which should be carefully studied by bacteriologists 

 and pathologists: I refer to the eye disease of the trout perch, small 



