of the water is of very great benefit ; I also believe that brook trout are 

 today being propagated and reared in hard water. 



Mr. Webster: At our St. Croix hatchery we have about 50,000 finger- 

 ling brown trout growing as fast as the brook trout without the slightest 

 trouble. The water there is as soft as rain water. Our success with 

 brook trout at St. Croix is right along the line of the success at Corry, 

 where the work has been carried on for 35 years. So far as I know the 

 only hatcheries in the United States where brook trout operations have 

 been conducted for 30 or 35 years without an epidemic at some time dur- 

 ing the period, are those supplied with soft water. Mr. G. Hansen, a 

 member of this Society, has a trout hatchery at Osceola, Wisconsin, and 

 during the 30 years of its operation there never has been an epidemic nor 

 have the fish ever died to any great extent. It is only seven miles from 

 St. Croix Falls, and conditions are practically the same as at the St. 

 Croix hatchery. 



Mr. E. W. Cobb, St. Paul, Minn. : Some time ago I observed the trout 

 at St. Croix hatchery and all that is said about those fish is true. The 

 hatchery building is peculiar in that it has four stories. The water is 

 very soft, while at St. Paul, 50 miles away, the water is very hard. The 

 temperature is the same and I think our methods are the same. Our 

 hatchery has been operated for a good many years, and, as far as I 

 know, has never had an epidemic. 



Mr. Titcomb : Our hatcheries are producing trout in both hard and 

 soft water. We have one hatchery, established about 40 or 50 years ago. in 

 which they raised brook trout for 30 or 35 years before they had any 

 serious trouble with them. That is a hard water proposition now used to 

 propagate brown and rainbow trout. I would not locate a trout hatchery 

 under any temperature conditions without testing with an inexpensive 

 plant for at least one year before advising the spending of any consider- 

 able sum of money, and the commissioner who recommends locating a 

 hatchery and spending $40,000 or more before it has been tested is taking 

 an unwarranted chance with the money of the tax payers. 



Dr. Embody : My paper referred alone to the temperature of the water. 

 Other factors such as oxygen and carbon dioxide were not considered. 

 We know little about the effects of those other factors upon trout. We 

 do not know how much oxygen they must have ; we do not know how 

 much carbon dioxide they can stand. Until we know the individual 

 effects and the combined effects of these various factors, we will not be 

 able to go to a spring and say, "This is fit or it is unfit for trout." In the 

 present state of our knowledge, the surest way to determine whether water 

 is suitable is to try it. 



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