COMMON TROUT. 93 



rishment from the substance contained in this bag, till by 

 degrees, as the fishes grow larger, the bag disappears, then 

 they begin gradually to assume the shape of fishes, and 

 having no further sustenance from this bag, they will seek for 

 food themselves. But as in so small a compass as this breed- 

 ing trough, there cannot be a sufficient quantity of small 

 insects to be found for their sustenance, they seek for more 

 room where they may meet with them in greater abundance ; 

 they follow then the current of the water, and slip through 

 the brass grate at the end of the box, where you should have 

 a large wooden tub, like a brewer's cooler, or a small clean 

 fish pond, covered with gravel to receive them, in which they 

 will grow in about six months considerably. 



" SECTION V. 



" To instruct my readers as much as possible, I shall add 

 several observations on the formation of these young Trouts. 



" 1. After an egg has been fluctuated by the sperma of 

 the male, which slips through an invisible opening into it, it 

 lodges in the white liquor under the shell and round the yolk, 

 which last is liquid and transparent, tending to a yellowish 

 colour, and seems to fill up the greatest space in the egg, 

 except the little white round it. 



" 2. So soon as this little animalcule has assumed the 

 nature and form of the fish, it appeareth that the yolk in the 

 egg is separated by a very thin skin from the outward hard 

 membrane. 



" 3. The fish itself, except the eyes, is very transparent, 

 and as liquid as a little mucilaginous water, yet in shape 

 longish ; it lies bent within the outward harder membrane of 

 the egg, and round the thin skin that covers the yolk. 



" 4. From this time the fish is to be considered as one 

 body grown to the yolk from the gills downwards to the 



