166 
SALMON. 
sight cannot be made to perform the function of the ear, nor 
the nerve of the latter that of the tongue; and also that the 
nerves of common sensation cannot supply the place of those 
which dhect the actions of muscular motion, although no skill 
in the use of the microscope has hitherto been able to discern 
a difference in their structure: it follows further that the receptive 
brain in one species of animal is not capable of eliciting the 
essential thoughts or instinctive feelings which are the natural 
characteristics of another. It is probable that the ordinary 
nervous fibres of the body of every separate creature possess 
some specific or peculiar mode of action in the conveyance of 
impressions; but it is the central organ which gives them their 
proper tone, from which the character of the race is formed. 
It is among these constant characters of the species, as it is in 
a large portion of the family, that we find the Salmon is not 
able to sustain life under a heat of climate that shall exceed 
what is found within the temperate regions of the earth; and 
it is known to be most at home and in greatest abundance as 
we proceed towards the north; although there is a limit also 
in that direction, and our more common species is compelled 
to shrink from the biting severity of the icy sea. Thus although, 
as we shall have to sherv, the roe of the Salmon is quickened 
into development in a shorter time in a mild climate, and by 
the application of a moderate degree of artificial heat, than when 
exposed to the icy cold of a northern river, and that the fish 
itself is so conscious of this as to refuse to ascend to its spawning 
bed when dissolved snow or floating ice is in the way, yet Dr. 
Davy has proved that in a heat above seventy degrees the 
young will not come to life. 
Through Sweden and Norway to the further bounds of 
Scandinavia the Salmon is in plenty, together with other species 
not known with us; and in the north of Scotland, as also in 
the Orkney and Shetland Islands it is said to reach its highest 
degree of beauty and perfection. It is to be remarked, however, 
that perhaps from the nature of the water, and the food, Avuth 
no little difference of climate, which may have impressed a large 
amount of peculiarity on the local varieties, the season of its 
chief excellency for the table is different, and even opposite in 
different districts; as are also the times and circumstances of its 
annual emigrations. In Scotland and the north of Europe, 
