THE ABTIFICIAL INCUBATION OF OVA. 31 



CHAPTER 11. 



THE ARTIFICIAL INCUBATION OF 'oVA. 



I NOW proceed to describe the best methods of 

 artificially incubating ova. Very much here depends 

 upon the natural advantages possessed by the pisci- 

 culturist as regards his water supply. If he has 

 a fine, clear spring, with a never-failing and full 

 supply, and a good faU for some distance after its 

 exodus, he is lucky, and has little difficulty to 

 contend with. If he has a stream near him which 

 seldom or never muds or thickens, but where there 

 is not enough fall, he may raise the water to the 

 required height, either by a ram or a small water- 

 wheel and pump, or by a simple force-pump and 

 cistern, employing manual labour to fill the cistern 

 at stated intervals. If, however, he has not sufficient 

 convenience, or the stream which he has at command 

 cannot be relied on for hatching purposes, he may 

 even trust to the main, provided the water be filtered 

 river water, and it be passed through some filtering 



