INSTINCT. 
« And binding nature fast in fate, 
Left free the human will,” ‘ 
is inconsistent with a striking passage in the 
Essay on Man :-— 
*« Who knows but He whose hand the lightning 
forms, 
Who heaves old ocean, and who wings the 
storms, 
Pours fierce ambition in a Czsar’s mind, 
Or turns young Ammon loose to scourge man- 
.- kind?’ 
But if the foregoing statement of the mode 
3 action of the only voluntary power which we 
_ are conscious of possessing over the train of our 
thoughts is correct, it does not appear possible 
_ to deny that ambition or any other passion may 
be infused into any human mind, without de- 
_ stroying the consciousness, or suspending the 
action of that voluntary power. And if we 
_ reflect on the characteristics of many nations 
that have appeared on the earth’s surface—on 
the taste and genius of the Greeks, the mili- 
_ tary spirit of the Romans, the restless energy 
__ of the northern nations, the maritime adven- 
ture and commercial enterprise of Britain and 
America—and contrast these with the stationary 
civilization of China, or the languid, if not re- 
trograde condition of Italy, Spain, or Greece— 
is it unreasonable to suppose that the designs of 
Providence as to the progress of the human 
race are sometimes carried into effect by an oc- 
casional infusion into many mdividuals of our 
species, of feelings and desires, of the ultimate 
_ object of which they have as little perception. 
_ as animals have of the purposes of their in- 
stincts? But to prosecute this speculation 
farther would be foreign to the object of this 
_ paper. 
~ It is still to be remarked, in regard to in- 
stincts, that they have been long and justly 
} regarded as among the most important pheno- 
_ mena in nature, in reference to the doctrine of 
_ final causes, or the inferences of design, and of 
__ the adaptation of means to ends in the arrange- 
_ ment of the universe; and it is important to 
set in as clear a view as possible the proper use 
to be made of them in that enquiry. 
Tn fact, the whole plan of the construction of 
_ all the different classes of animals bears refe- 
rence to the instincts with which they are en- 
dowed, and would be useless without them. 
If the fangs and claws of the lion, the jaws 
and stomachs of the ox or the camel, or the bill 
and gizzard of the turkey, are admirably 
adapted for the prehension and subdivision of 
their respective aliments, as well as their organs 
of digestion for the assimilation of their food, 
all these provisions would have been useless, 
_ but for the instincts-which nature has im- 
; planted in these animals, by which their proper 
nourishment is sought, and the first part of the 
process of its assimilation is directed. 
The mutual adaptation of instincts to struc- 
ture, of structure to instincts, and of both to 
the ends of their creation throughout every 
part and function of an animal, and throughout 
every grade of the animal creation, has been 
illustrated by many authors, but perhaps most 
efficiently by Paley, as the most satisfactory of 
all the indications of the adaptation of means 
25 
to ends which the study of the universe pre- 
sents. 
It is indeed so clearly the fact that all the 
arrangements of the structure of an animal are 
subordinate to the instincts with which it is 
endowed, that the whole study of Comparative 
Anatomy, and the whole classification of ani- 
mals in so far as it is founded on their varieties 
of structure, require to be regulated by this 
consideration. The general principle by which 
the details of these sciences are held together 
may be stated to be this:—that while nature 
has observed a certain unity of plan in the con- 
struction, certainly of all the vertebrated, per- 
haps to a certain degree of all, animals, she has 
likewise introduced in all parts of the scale 
just such modifications of that plan as the si- 
tuation in which each animal is placed, and the 
office it has to perform, or as the French ex- 
press it, as the conditions of its existence, 
demand ; and then has implanted in it pre- 
cisely such instincts as are required to enable it 
to maintain itself—to turn those provisions to 
account—to enjoy its allotted portion of sen- 
sitive pleasure, and to fulfil the other objects of 
its creation, under those conditions. 
The study of the instincts of animals may 
be said, therefore, to hold a necessary interme- 
diate place between the study of their struc- 
ture, and that of the ends or objects of their 
creation—the structure being subordinate to 
the instincts, as these are subordinate to the 
objects of existence ; and it is by attending to 
them that the immense extent and infinite va- 
riety of the adaptation of means to ends in the 
animal creation is perhaps most distinctly per- 
ceived. 
It is stated by Mr. Whewell, that although 
the study of Final Causes has been often re- 
jected from the science of Physiology, yet 
it has been found impossible to keep them se- 
parate. ‘The assumption of final causes in 
this branch of science is so far from being ste- 
rile, that it has had a large share in every disco- 
very which is included in the existing mass of 
knowledge. The doctrine of the circulation of 
the blood was clearly and professedly due to 
the persuasion of a purpose in the circulatory 
apparatus.”* But there appears to be some 
ambiguity in this statement. The term 
physiology is properly applied to the in- 
vestigation of the physical causes of the 
phenomena of life—of the powers which 
are in operation, and the conditions under 
which they operate, in producing these phe- 
nomena. It is true that the different func- 
tions of life are dependent on one another in 
any individual animal ; and the science of phy- 
siology is most conveniently taught by arrang- 
ing their functions in the order of their de- 
pendence, and assigning, therefore, the final 
cause of each, after explaining the manner in 
which it is carried on. It is true, also, that the 
study of the uses to which the different func- 
tions are subservient, i. e. the study of final 
causes, has often led to the detection of phy- 
sical causes in this as in other sciences.. But 
* Hist. of the Inductive Sciences, vol. iii. p. 467, 
