102 FISH HATCHING. 



however for an axiom, that the higher the 

 temperature for the egg the "weaker the 

 fish produced from that egg, — anything 

 above 50° is weakening. 



The first fish again hatched out from a 

 batch are the weakest, the last are the 

 healthiest ; when however they once begin 

 to hatch the}^ wall come out all in a mass, 

 two, three, or four thousand of a morning. 

 The proper temperature for trout and salmon 

 eggs is 40° to 45", and again I repeat it, any- 

 thing over 50" is weakening. 



Grayling, however, appear to be an excep- 

 tion to this rule ; Mr. Ponder has obtained a 

 fair supply of the ova of these fish, which 

 the Thames Angler Preservation Society are 

 about to introduce into the Thames. The 

 quantity obtained amounted to between 



