24 PRACTICAL TROUT CULTURE. 



comes increased danger : the fungoid growths 

 which, in spite of all our care, will sometimes 

 appear in our hatching-trays or rearing-boxes, are 

 too often evidence of a too elevated temperature. 

 Attempts made to keep down the temperature by 

 passing the water through a refrigerator filled with 

 ice have thus far failed, even when the experiment 

 has been performed upon a very small scale. 

 Other fish may be hatched at a much higher tem- 

 perature ; shad eggs not coming to maturity below 

 70, and gold fish have been bred even when the 

 thermometer stood over a hundred ; but trout are 

 a peculiar fish, and 55 is the highest at which 

 their spawn will produce vigorous and healthy 

 young. The question is often asked : given the 

 capacity and temperature of the water supply, 

 what amount of trout will it support ? To an- 

 swer this we sought diligently the pages of all 

 authorities upon fish culture, but in none of them 

 was the subject even mentioned. Inquiry was 

 made of those who were supposed to be thoroughly 

 posted in every branch of the art, but no informa- 

 tion could be obtained. We at once entered upon 

 a course of experiments, resulting in proving that 

 for each gallon of water per minute at the temper- 

 ature of 50 degrees, ten pounds of trout can be 

 sustained ; thus the Troutdale spring delivers a 

 volume of water which at the dryest season has 



