OF TEE SALMONIDjE. 59 



lightly upon the ova, and the whole is 

 saturated with cold water. Finally, a layer 

 of broken ice tops the whole, the lid is 

 screwed down, and the box taken off imme- 

 diately to the ice-honse. Simple as this 

 process appears to be, it is incredible how 

 many small details are involved in it ; and 

 if it is not done with most careful manipu- 

 lation, the chance of survival for the ova 

 is small. Long practice has made Mr. 

 Youl an adept in the art of giving those 

 nice touches to the materials which our 

 unaccustomed hands failed to attain with 

 the two boxes we attempted to pack. The 

 object of the charcoal at the bottom of the 

 boxes is to absorb any carbonic acid gas 

 evolved from the decomposition of dead 

 ova; the moss prevents motion among the 

 ova, and gives them a soft bed, while it also 

 assists in taking up the products of decom- 

 position and furnishes at the same time a 

 small supply of oxygen. Thus we have 

 within the ice living vegetable organisms, 

 with animal bodies whose life is in suspen- 

 sion, each feeding the other with that which 



