THE 
CYCLOPADIA. 
OF 
ANATOMY AND PHYSIOLOGY. 
Pi INSTINCT.—This word is often applied to 
~ the mental acts of the lower animals, as if it 
"were truly applicable to the whole of these 
acts 5 but a little consideration will shew, 
; t, that this word, in its more approved and 
t acceptation, is applicable only to a 
art of the mental operations, which may be 
ferred from the observation of the actions and 
habits of animals; and secondly, that in this 
‘Testricted sense, the term is applicable to a 
part of the operations of the human mind itself; 
and that the subject of instinct cannot be tho- 
‘roughly understood, unless information regard- 
ay it is sought in the consciousness of our 
Own minds, as well as in the observation of 
_ Other living beings. The study of this subject 
‘is therefore equally important as a part of 
“natural history, of mental philosophy, and of 
physiology ; and is a good illustration 
the necessity of this latter science being 
ased on the observation and generalization of 
the laws and conditions of vital action through- 
ut the whole extent of the animal creation. 
It is obvious, indeed, that various mental 
acts, of which we are conscious in ourselves, 
nay be inferred, with perfect confidence, to 
take place throughout the whole range of the 
imal kingdom, and even that some of them 
be performed with greater energy and 
sion in some of the lower tribes than in 
a. The different external senses attain their 
highest perfection in different animals ; that of 
‘smell, for example, probably in the predaceous 
immialia, that of touch in the antenne of 
, and that of sight in the predaceous 
‘birds ; it is not likely that any one is enjoyed 
in its highest perfection by man; and what 
have been accurately distinguished from mere 
; a Ill. 
sensations as the perceptions of external things, 
i.e. the notions as to the qualities of these, 
which naturally present themselves to our minds 
in consequence of sensations being felt, would 
seem in various instances to follow the sensa- 
tions more quickly and more surely in other 
animals than in us; for it is generally allowed 
that what appear to be acquired perceptions of 
the eye to us, i.e. the notions of the distance, 
size, and form of visible objects, are instanta- 
neously made known to many of the lower 
animals the very first time that those objects 
make impressions on their retine; the faculty 
of Intuition, which we must admit as part of 
the source of our own knowledge, appears to 
exist in greater perfection in other animals, and 
the notions of external things which they thus 
acquire are amply sufficient to regulate their 
muscular motions. 
It is equally plain that many of the strictly 
mental acts, of which our complex trains of 
thought are composed, are habitually performed 
by animals ; that they have a perfect recollec- 
tion of past sensations, implying the exercise of 
the powers of memory and of conception ; that 
the emotions of fear, of joy, of affection, of 
anger, even of jealousy, are as distinctly indi- 
cated by their actions as by those of man; that 
under the influence of these emotions their 
mental operations are excited or depressed, and 
their attention fixed or distracted, and their 
volition excited, as in our own case ; and that 
their actions are habitually guided by a clear 
perception, or rather, we should say, by conti- 
nual correct applications, of a first principle 
of belief, which is generally admitted to 
be an ultimate fact in the constitution of the 
human mind, and onwhich much stress has been 
B 
