THE COMMON TROUT 263 
nation here is the likeliest—namely, that in great and deep 
lakes, fed by countless streams nourishing immense numbers 
of small trout, all the trout would remain small, were it not 
that some of their number, favoured by ample depth and 
expanse of water and by their own superior energy, gradually 
obtain some advantage, become so much larger than their 
fellows, that, when pressed for food, they take to preying on 
their own kind. For these so-called ferox have well earned 
the title of ferocious, being habitual cannibals. The result is 
to the advantage of the community, for it is to be noted that 
in lakes fed by numerous streams affording unlimited spawning- 
ground, trout will multiply up to the very limits of subsistence, 
but all will remain insignificant in size, unless pike or ferox 
are present to act as a check upon numbers, in which case the 
average weight of the trout will be considerably greater, and 
their quality better, through the reduction of the number of 
mouths to feed. 
It may be observed, parenthetically, that it would be an 
exceedingly rash proceeding to introduce pike into a lake 
which is overstocked with small trout in order to increase their 
size. The proper course to that end is to limit the spawning- 
ground by erecting impassable barriers upon some of the 
tributary streams, at the same time doing all that is possible to 
improve the food supply. 
Before dismissing the so-called Salmo ferox as a mere 
variant, full or overgrown, of the common trout, it is to be 
noted that, as in all the rest of the species, much of the 
external colour is exceedingly transient. Sometimes ferox 
from 8 lb. to 15 lb. are grey and silvery when landed; at 
other times they are intensely dark, with numerous spots and 
fiery sparkles. But I have seen some of these dark monsters, 
left in a cool place overnight, appear quite bright and salmon-~ 
like in the morning. In fact, it is impossible to judge of the 
permanent skin colour and markings of any trout unless it is 
wrapped in a wet cloth and so left for some hours. 
