TROUT BREEDING. 65 



precaution should be taken to exclude vermin from tlie 

 hatching-house, the light should be modified with shutters 

 or curtains to the windows, and the sunshine which pro- 

 motes the growth of byssus, should not be allowed to fall 

 on the eggs. Byssus, which is a fungous growth, is perhaps 

 the greatest enemy ; with its long filaments it closes upon 

 and destroys the vitality of the egg ; when one is destroyed 

 the dead egg promotes its growth for the destruction of 

 others, until a score may be clasped by its long fingers. 

 The eggs should be disturbed as little as possible during 

 incubation. An accumulation of sediment in one place can 

 be removed by a glass syphon or syringe to some extent, 

 but no dependence should be placed on such remedies, as 

 the perfect filtration of the water is the main reliance. 



There are few things more interesting than the observa- 

 tion of the gradual development of embryo and life in the 

 egg of a trout. When the time of its deliverance ap- 

 proaches, the young fish is restive in its little prison. A 

 gleam of sunshine, or the warmth imparted by the hand to 

 the vial containing the ova when examining it, incites it to 

 vigorous struggles for liberty. At last the shell is broken, 

 the head appears, then the pectoral fins, then the tail ; it 

 comes forth and its house floats away. Although helpless, 

 it is not needy ; an umbilical sac three times the bulk of 

 its body is provided. Apparently exhausted by its late 

 efi'orts, and weighed down with its bag of provisions, it lies 

 on it, or rests on its side, or stands on its head ; any posi- 

 tion suits it; its eyes, unless closely inspected, the only part 

 visible. Its body three-eightihs of an inch long, and not 



