On The Parts Of Animals   

a half glimpse of persons that we love is more delightful than a
leisurely view of other things, whatever their number and dimensions.
On the other hand, in certitude and in completeness our knowledge of
terrestrial things has the advantage. Moreover, their greater nearness
and affinity to us balances somewhat the loftier interest of the
heavenly things that are the objects of the higher philosophy. Having
already treated of the celestial world, as far as our conjectures
could reach, we proceed to treat of animals, without omitting, to the
best of our ability, any member of the kingdom, however ignoble. For
if some have no graces to charm the sense, yet even these, by
disclosing to intellectual perception the artistic spirit that
designed them, give immense pleasure to all who can trace links of
causation, and are inclined to philosophy. Indeed, it would be strange
if mimic representations of them were attractive, because they
disclose the mimetic skill of the painter or sculptor, and the
original realities themselves were not more interesting, to all at any
rate who have eyes to discern the reasons that determined their
formation. We therefore must not recoil with childish aversion from
the examination of the humbler animals. Every realm of nature is
marvellous: and as Heraclitus, when the strangers who came to visit
him found him warming himself at the furnace in the kitchen and
hesitated to go in, reported to have bidden them not to be afraid to
enter, as even in that kitchen divinities were present, so we should
venture on the study of every kind of animal without distaste; for
each and all will reveal to us something natural and something
beautiful. Absence of haphazard and conduciveness of everything to an
end are to be found in Nature's works in the highest degree, and the
resultant end of her generations and combinations is a form of the
beautiful.
If any person thinks the examination of the rest of the animal kingdom
an unworthy task, he must hold in like disesteem the study of man. For
no one can look at the primordia of the human frame-blood, flesh,
bones, vessels, and the like-without much repugnance. Moreover, when
any one of the parts or structures, be it which it may, is under
discussion, it must not be supposed that it is its material
composition to which attention is being directed or which is the
object of the discussion, but the relation of such part to the total
form. Similarly, the true object of architecture is not bricks,
mortar, or timber, but the house; and so the principal object of
natural philosophy is not the material elements, but their
composition, and the totality of the form, independently of which they
have no existence.
The course of exposition must be first to state the attributes common
to whole groups of animals, and then to attempt to give their
explanation. Many groups, as already noticed, present common
attributes, that is to say, in some cases absolutely identical
affections, and absolutely identical organs,-feet, feathers, scales,
and the like-while in other groups the affections and organs are only
so far identical as that they are analogous. For instance, some groups
have lungs, others have no lung, but an organ analogous to a lung in
its place; some have blood, others have no blood, but a fluid
analogous to blood, and with the same office. To treat of the common
attributes in connexion with each individual group would involve, as
already suggested, useless iteration. For many groups have common
attributes. So much for this topic.
As every instrument and every bodily member subserves some partial
end, that is to say, some special action, so the whole body must be
destined to minister to some Plenary sphere of action. Thus the saw is
made for sawing, for sawing is a function, and not sawing for the saw.
Similarly, the body too must somehow or other be made for the soul,
and each part of it for some subordinate function, to which it is
adapted.
We have, then, first to describe the common functions, common, that
is, to the whole animal kingdom, or to certain large groups, or to the