58 Trout Culture. 



tube, it will appear as a mere threadlike body, 

 with two very prominent eyes, resting on a 

 round yellow ball of oil. On using a lens it 

 will be seen that the blood-vessels are spread 

 out into and over this vesicle of oil or yolk, 

 whence the necessary food is obtained in this, 

 which is called the " Alevin " stage of a trout's 

 existence. 



Nature thus caters for the young fish for 

 from a month to seven or eight weeks, according 

 to temperature ; heat accelerating and cold 

 retarding the consumption of the oil in the 

 vesicle and the development of the body. 

 Having all its needs supplied, it rests pretty 

 quietly for a day or two, and only wriggles 

 at intervals ; but about the fifth day from the 

 general hatching out of that batch of eggs, a 

 general desire to hide becomes manifest. Ac- 

 cordingly in every angle of the trough, except 

 where the water is disturbed by the stream 

 falling in from the trough above, there will be 



