CARE OF ALEVINS. 145 



Great vigilance is now required ; and wherever there 

 is a suspected place, a fine wire screen should be 

 placed below it to catch any that escape. I 'once 

 noticed a drop or two of water trickling from the head 

 of one of my hatching troughs, and immediately placed 

 a large screen under it. Two days afterwards I found 

 nearly a thousand young trout on the screen, although 

 I did not then, and could never afterwards, discover any 

 hole for them to get through. The wire netting at the 

 regular outlet should also be particularly watched, as 

 the constant cleaning of the screen wears out the wire, 

 and may make a fracture in it before it is suspected. 



The trout at this age are the incarnation of perver- 

 sity. They will go just the opposite way from which 

 you want to have them, and if there is any place where 

 you do not want them to go, they will be sure to col- 

 lect in it in vast numbers, and when you try to drive 

 them away they will dive their heads into the gravel 

 and stick to the spot with a truly wonderful tenacity ; 

 or if you succeed in forcing them off a little way, they 

 will return with' redoubled momentum, and charge 

 again and again, with a persistency which is as sur- 

 prising as it is annoying. As the tissue of their struc- 

 ture is such an exceedingly delicate one that they can- 

 not be pushed forcibly, even with a feather, they would 

 be very difficult to manage if you wished to have them 

 leave any particular spot where they had gathered, 

 were it not for the knowledge' of one instinct that they 

 have. This instinct is to avoid agitated water. They 

 have, a great dislike to troubled waters, and will usually 

 leave with one accord any spot where the water is 

 7 J 



