CABT>. 
13 
which they are adapted predominates over understanding or 
reflection; yet when proportionate magnitude is added to pecu- 
liarity of structure, the former must he regarded as an important 
element in the display of the faculty of understanding. There 
IS a peculiarity in the nerves, especially those of the senses, as 
of sight, taste, and hearing, in that neither of them can he 
taught to perform the functions of another;, and there is pre- 
sumptive proof that this remark may be extended to essential 
portions of the brain itself; and that it is in tliis the conscious 
identity of every creature resides, or from which it derives its 
existence, which therefore intrinsically constitutes the true dis- 
tinction of species. If there be a time when the nature of any 
creature appears to be substantially changed, so that the fearful 
becomes bold, or the contrary, vrhen hunger suspends the 
indulgence of its appetite, and the wanderer confines itself to 
one solitary spot, it is when by the temporary preponderance 
of one specific nervous energy the action of the others appeal's 
superseded; and this most frequently occurs at the season of 
procreation; at which time Pennant informs us that the cautious 
and cunning Carp becomes so simple as to suffer itself to be 
tickled, handled, and caught by any one who will attempt to 
do it. 
Put the outward senses of this fish, as well as its inward 
consciousness, arc acutely alive to sensation; of which one set 
of instruments is the barbels at the mouth, which in some 
degree corresponds to what is also a character of the Cod family, 
1 he pad also in the roof of the mouth is elastic and highly 
sensitive, being furnished with a large number, of nerves, which 
are derived from the eighth pair as they arise from the brain, 
and are peculiarly fitted to receive these impressions. That these 
fishes are brought together by sounds is a proof of the quicknef-s 
of their hearing as well as of their knowledge of the object for 
which they arc made to assemble; in which particular again 
they resemble the Mullets; and by dissection it is found that 
their oigans of hearing are not a little complex; with some 
reference again to the air-bladder, which, unlike what is found 
in most other fishes, is double in the Carp, as well as in the 
Tench and some others of this family ; and this doubling is 
formed by means of a constriction towards its upper portion; 
from the second division of which proceeds a tube, which 
