60 REPORT ON ARTIFICIAL FISH-CULTURE. 



In hatching fish in new waters, trials of their 

 acclimation can he successfully made. I may give 

 here striking examples in citing my experiments 

 at the College of France, under circumstances 

 where I did not promise myself success. Young 

 salmon hatched in my laboratory, and placed af- 

 terwards in an artificial pond fed by a single 

 stream of the water of the Arcueil, grew as well 

 as if they had lived in the Rhine, as I was able 

 to satisfy myself by a comparison. They are 

 hardly four months old, and already their length 

 is sixty millemetres, of which they have gained 

 twelve during the last twenty-four days, a remark- 

 able growth which may be attributed, without 

 doubt, to the particular nourishment they receive, 

 of which they show themselves greedy. 



But to return to our hatching apparatus and 

 the eggs which are in progress of development. 

 Here a second problem is presented: what becomes 

 after birth of the young fish hatched by millions 

 in the narrow drains where the eggs are depo- 

 sited? This second problem will not be more 

 difficult to answer than the first. The arrange- 

 ment of the locality will answer for all exigen- 

 cies. As soon as the newly-hatched fish are strong 

 enough to swim, they will follow the course of 

 the stream, which will draw them to the meadow 

 by the extremity of the glass house, through 



