64 PRACTICAL TROUT CULTURE. 



of spawning races used in the natural impreg- 

 nation of ova, reserving for another chapter the 

 entire process of artificial fertilization. Long ere 

 fish culture was oknwn and recognized as a science, 

 it was the custom of many who owned trout 

 ponds to allow the fishes, during the spawning 

 season, access to the spring-head, and after all 

 their spawn had been deposited they were driven 

 back to the pond, and their return prevented by a 

 screen. In some parts of our country, especially, 

 we have understood, upon Long Island, series of 

 ponds were constructed in pairs, as in the annexed 

 cut. Let A represent the main pond, connected 

 by a sluice with the pond B by means of a short 



FIG. 12. 



race-way and gate C, the water flowing from B to 

 A. During the spawning season the gate (C) was 



