20 THE SALMON FISHERIES. 
“Tt follows,” he continues, “that they must remain in the 
salt water until they attain maturity, when, impelled by the 
natural instinct, they resort to the places where they were 
bred, there to consummate the final act of their existence. I 
say it follows, for it is to be noticed that in the ascending 
shoals none but mature fish areto be discovered. The 
individuals of each distinct shoal— however much the 
several varieties of fish may differ from each other, as they 
do in size and quality—do not differ among each other. 
They are all of the same or nearly the same magnitude, 
but all of equal age so far as the conditions of size and 
maturity can guide the judgment. There is no variation of 
grilse, or other definition by which the salmon of the 
Eastern American, or European streams may be dis- 
tinguished.” 
In support of his own testimony Mr. Anderson quotes the 
following passage from the Report of Professor Baird, 
describing the operations of Mr. Livingston Stone when 
collecting salmon eggs in the Sacramento River for the 
United States Commissioner of Fisheries :— 
“A substantial timber grating was built across the 
stream (the McLeod branch of the Sacramento). The 
grating was an entire bar to the salmon, no opening being 
left to permit their passing above it, and the experiment 
satisfied Mr. Stone that salmon which ascended the river to 
spawn never returned to the sea. The number which had 
passed above the grating, before it was finished, he 
estimated at hundreds of thousands, while thousands 
crowded against its lower sides when completed, vainly 
attempting to pass. As to their return, he failed to 
discover a single live salmon, though thousands of dead 
ones lodged against the upper side of the grating.” 
This question is of so much practical importance that 
