II 
At Howietoun I use boxes, each of which will rear 15,000 
Lochleven Trout fry for five or six months after hatching, and 
this without any appreciable loss, but I do not care to lay 
down more than 20,000 eggs on the grilles in each box, the 
size of the egg being 35,000 to the gallon. I find that if the 
eggs are laid down any thicker than this there is a decided 
difference in the vitality of the alevins and feeding powers 
of the fry. 
I will now consider the Hatchery as a factor in the culti- 
vation of migratory Salmonide, restricting myself for the 
present to those species placed by Dr. Giinther in the 
group Salmones either with a wide geographical range, as 
Salar, Trutta, and Cambracus, or limited to Great Britain 
and Ireland, as Brachypoma and Gallivensis, merely point-. 
ing out that while touching on the general conditions 
common to the increase of the above named species, the ex- 
termination of the Bull Trout on the Tweed and the Sea 
Trout on the Forth forms a very serious point to discuss in 
treating of the culture of the Salmon, and that the best results 
can only be obtained by the careful protection and arti- 
ficial production of the species best suited to each particular 
district. The objects here are to increase Salmones whose 
pastures are in the sea, and whose nurseries are in the rivers. 
The size of the river has no fixed relation to the number 
and weight of fish caught in its estuary and contiguous sea- 
board, and if a very large number of smolts were annually 
turned in immediately above the tidal waters the stock of 
Salmones would be increased by a proportion of the number 
turned in, fixed only by the conditions of food and of 
natural enemies in the estuary and adjoining sea. I do not 
mean to say for an instant that all the fish reaching 
maturity would return or attempt to return to the mouth of 
the river in which they were liberated as smolts, but I think 
