74: 



this regard that the ponds are not fished oftener than 

 once in two or three years. Certainly this is small, 

 and indeed some ponds return sixty, seventy, and even 

 eighty francs per hectare. 



The most highly esteemed carp establishments are 

 those of Dubisch in Silesia, which have frequently 

 been mentioned of late years, and have given the best 

 results. A hectare has yielded, according to official 

 reports, as high as one hundred and thirty-two francs, 

 a result which has never been exceeded ; but this 

 method involves much care and labor. This is a very 

 excellent result, but how insignificant compared with a 

 jdeld of seven hundred francs per hectare, which I have 

 mentioned in the beginning. Truth compels me to say 

 that it is not with the carp that this climax is reached, 

 but with another fish. 



I have thought from the beginning that it would 

 be possible to replace the carp by another of our fresh 

 water fish, such as the eel or trout, the prices of which 

 are much higher. 



For the culture of the eel special conditions are 

 essential, and the habits of the fish are such as to 

 make its culture in ponds uncertain and undesirable. 



On account of its high price the trout has already 

 been made the subject of many experiments, but of all 

 those I have seen undertaken I have not observed a 

 single one which has been a success from a commercial 

 point of view. The reason can be easily stated : 



First, the ordinary pond rarely contains water of a 

 temperature during the summer sufficiently low to suit 

 the trout or even to keep it alive, for this fish will not 

 endure a temperature above i8° centigrade ; besides, 

 the calm and stagnant water of the pond is not calcu- 

 lated to please it. 



It is a fish of rapid streams, of waters incessantly 

 moving and aerated, of the rapid cascades which it 

 ascends joyfully even when they boil like a cauldron ; 



