186 BRITISH FRESH-WATER FISHES 
unlearned men of the open air find their way to the truth 
before those of the museum and laboratory, but in this instance 
practical fishermen divined the secret earliest, as may be seen 
from a passage in Scott’s Fair Maid of Perth, published in 
1828. ‘Eachin resembles Conachar,” said the glover, “no 
more than a salmon resembles a parr, though men say they 
are the same fish in a different state.” The question was not 
settled until Mr. Shaw had conducted a lengthy series of 
experiments in the Stormontfield ponds during a number 
of consecutive years from 1830 onwards. His report, printed 
in the Edinburgh New Philosophical Fournal, 1836, followed by 
a paper he read before the Royal Society of Edinburgh in 1837, 
left no room for doubt as to the identity of salmon and parr, 
although, as above mentioned, Couch stoutly refused to adopt 
this conclusion. 
At the age of fifteen months, the majority of salmon parr, 
which have lived so far like common brook-trout, feeding on 
The Smolt insects, worms, and such-like small prey, begin to get 
stage. restless, to drop out of the rivulets which have 
hitherto harboured them, and to congregate in shoals in the 
main river. Some individuals postpone this movement till they 
are seven-and-twenty months old, or thereby, but it is probable 
that a large majority prepare for the sea trip in April and May of 
their second spring. This movement is heralded by a remark- 
able change in the appearance of the fish, which now measure 
on an average about five inches in length. The olive green of 
the back turns into a bluish tint, and the gay motley of the 
sides, never more brilliant than at this season, is hidden by the 
secretion of guanin under the scales, which gives a uniform 
covering of brilliant silvery lustre, known to fishermen as the 
sea-jacket. In this new guise they make their way to the sea, 
where, as they divine by hereditary instinct, more abundant 
provender awaits them than they can find in their native 
streams. 
We lose sight of the smolts now, and for an uncertain 
- soe 
