MIDDLETHIRD HATCHING-HOUSE. 123 



for no use. The proportion of injury due to different degrees of 

 light I intend to treat of further on, when the Milneholme experi- 

 ments are recorded. 



Fungus is another cause of injury. There are two forms, one 

 generally referred to as byssus, the other as saprolegnia, akin to 

 S. ferax, of which so much has been heard in connection with the 

 salmon disease. Byssus is harmless in a well-regulated establish- 

 ment ; it grows slowly (for a fungus) ; it is easily seen ; it never 

 grows at all without a preventible cause, and that cause is one 

 that never ought to exist in any fishery, viz., dead animal matter. 

 Only go over the eggs three times a week and there will be no 

 byssus. The other fungus is a very different thing, the most 

 subtle and Protean of monsters, especially if the water is clear. It 

 may have laid hold on the ova for days uuperceived. No amount 

 of attention will save the ova if once they be attacked. Shutting 

 out all light decreases the vitality of the ogre, increasing the 

 current strengthens the embryo in the eggs ; but this fungus must 

 be met in an earlier stage, the boxes must be made disagreeable to 

 him before the eggs are laid down. This is done at this fishery in 

 the way recommended by Mr. Livingston Stone, Domesticated Trout, 

 p. 48. He says : " Char the plank. This I consider very important 

 indeed if you use plank, for you cannot be certain without charring 

 it. Do not imagine that you are safe from fungus because your 

 hatching- boxes themselves are well guarded from it. It may grow 

 in the aqueduct and be borne down by the stream, and before winter 

 is over you may find to your dismay that it has fastened its 

 fatal grasp on your eggs ; if so, they are ruined. There is no 

 remedy for fungus which will make healthy fish of the eggs 

 attacked." 



All the hatching-boxes are charred every season. The process 

 is very simple, and costs less than paint, and much less than 

 asphalt varnish. A hot iron, made heavy for the purpose, and kept 

 square at the edges, is rapidly passed over the inside of the box, 

 and voild tout. Frost is a danger, but protection must be sought 

 in the construction of the hatching-house itself, and not in the 

 hatching-box. The first pair of 



