114 DOMESTICATED TROUT. 



the character and effect of the four sources of injury 

 mentioned. 



i. Fungus* ' There is no word in the fish breeders' 

 vocabulary that is so associated with loss and devasta- 

 tion as the word " fungus." There is nothing with 

 which he has to deal that is so insidious and deadly 

 as fungus. This silent, invisible foe is sure to come, if 

 any door is left open for its entrance. It often fastens 

 its irrevocable grasp on the eggs, without giving any 

 sign of its approach. Once present in the water, it 

 spreads over everything. It cannot be removed. It 

 never lets go its hold. It is fatal in its effects. 



Most of my readers know that fungus is a vegetable 

 growth of a low order, which makes its appearance 

 almost invariably where there is water, and especially 

 on newly cut wood, on which it eventually becomes a 

 mass of nearly colorless or milky slime. f What makes 

 it so peculiarly noxious is, that each one of its cells, 

 whether detached or not, is a reproductive seed, 

 that is to say, a perfect reproducing plant in itself. 

 Consequently, when it is torn up anywhere, or broken 

 in pieces, instead of being destroyed, it only becomes 

 more powerful to injure. 



So where any fragment of fungus falls, however 

 small, even if it is only one microscopic cell, it imme- 

 diately proceeds to grow, and produce other similar 



* "Fungus, a large natural order of plants, comprehending 

 the microscopic plants, which form mould, mildew, smut, etc. 

 The fungi constitute one division of the Linnean class of Cryp- 

 togamia." Webster's Dictionary. 



I On hard wood and knotty wood it is sometimes black, but 

 the common form of growth is nearly colorless. 



