Cicero's Tusculan Disputations
trunks; in order to which every individual has within itself such
fertile seed that many are generated from one; and in vegetables this
seed is enclosed in the heart of their fruit, but in such abundance
that men may plentifully feed on it, and the earth be always replanted.
With regard to animals, do we not see how aptly they are formed for the
propagation of their species? Nature for this end created some males
and some females. Their parts are perfectly framed for generation, and
they have a wonderful propensity to copulation. When the seed has
fallen on the matrix, it draws almost all the nourishment to itself, by
which the foetus is formed; but as soon as it is discharged from
thence, if it is an animal that is nourished by milk, almost all the
food of the mother turns into milk, and the animal, without any
direction but by the pure instinct of nature, immediately hunts for the
teat, and is there fed with plenty. What makes it evidently appear that
there is nothing in this fortuitous, but the work of a wise and
foreseeing nature, is, that those females which bring forth many young,
as sows and bitches, have many teats, and those which bear a small
number have but few. What tenderness do beasts show in preserving and
raising up their young till they are able to defend themselves! They
say, indeed, that fish, when they have spawned, leave their eggs; but
the water easily supports them, and produces the young fry in
abundance.
LII. It is said, likewise, that tortoises and crocodiles, when they
have laid their eggs on the land, only cover them with earth, and then
leave them, so that their young are hatched and brought up without
assistance; but fowls and other birds seek for quiet places to lay in,
where they build their nests in the softest manner, for the surest
preservation of their eggs; which, when they have hatched, they defend
from the cold by the warmth of their wings, or screen them from the
sultry heat of the sun. When their young begin to be able to use their
wings, they attend and instruct them; and then their cares are at an
end.
Human art and industry are indeed necessary towards the preservation
and improvement of certain animals and vegetables; for there are
several of both kinds which would perish without that assistance. There
are likewise innumerable facilities (being different in different
places) supplied to man to aid him in his civilization, and in
procuring abundantly what he requires. The Nile waters Egypt, and after
having overflowed and covered it the whole summer, it retires, and
leaves the fields softened and manured for the reception of seed. The
Euphrates fertilizes Mesopotamia, into which, as we may say, it carries
yearly new fields.[228] The Indus, which is the largest of all
rivers,[229] not only improves and cultivates the ground, but sows it
also; for it is said to carry with it a great quantity of grain. I
could mention many other countries remarkable for something singular,
and many fields, which are, in their own natures, exceedingly fertile.
LIII. But how bountiful is nature that has provided for us such an
abundance of various and delicious food; and this varying with the
different seasons, so that we may be constantly pleased with change,
and satisfied with abundance! How seasonable and useful to man, to
beasts, and even to vegetables, are the Etesian winds[230] she has
bestowed, which moderate intemperate heat, and render navigation more
sure and speedy! Many things must be omitted on a subject so
copious--and still a great deal must be said--for it is impossible to
relate the great utility of rivers, the flux and reflux of the sea, the
mountains clothed with grass and trees, the salt-pits remote from the
sea-coasts, the earth replete with salutary medicines, or, in short,
the innumerable designs of nature necessary for sustenance and the
enjoyment of life. We must not forget the vicissitudes of day and
night, ordained for the health of animated beings, giving them a time
to labor and a time to rest. Thus, if we every way examine the
universe, it is apparent, from the greatest reason, that the whole is
admirably governed by a divine providence for the safety and
preservation of all beings.
If it should be asked for whose sake this mighty fabric was raised,
shall we say for trees and other vegetables, which, though destitute of
sense, are supported by nature? That would be absurd. Is it for beasts?
Nothing can be less probable than that the Gods should have taken such
pains for beings void of speech and understanding. For whom, then, will
any one presume to say that the world was made? Undoubtedly for
reasonable beings; these are the Gods and men, who are certainly the
most perfect of all beings, as nothing is equal to reason. It is
therefore credible that the universe, and all things in it, were made
for the Gods and for men.
But we may yet more easily comprehend that the Gods have taken great
care of the interests and welfare of men, if we examine thoroughly into
the structure of the body, and the form and perfection of human nature.
There are three things absolutely necessary for the support of life--to
eat, to drink, and to breathe. For these operations the mouth is most
aptly framed, which, by the assistance of the nostrils, draws in the
more air.
LIV. The teeth are there placed to divide and grind the food.[231] The
fore-teeth, being sharp and opposite to each other, cut it asunder, and
the hind-teeth (called the grinders) chew it, in which office the
tongue seems to assist. At the root of the tongue is the gullet, which
receives whatever is swallowed: it touches the tonsils on each side,
and terminates at the interior extremity of the palate. When, by the
motions of the tongue, the food is forced into this passage, it
descends, and those parts of the gullet which are below it are dilated,
and those above are contracted. There is another passage, called by
physicians the rough artery,[232] which reaches to the lungs, for the
entrance and return of the air we breathe; and as its orifice is joined
to the roots of the tongue a little above the part to which the gullet
is annexed, it is furnished with a sort of coverlid,[233] lest, by the
accidental falling of any food into it, the respiration should be
stopped.
As the stomach, which is beneath the gullet, receives the meat and
drink, so the lungs and the heart draw in the air from without. The
stomach is wonderfully composed, consisting almost wholly of nerves; it
abounds with membranes and fibres, and detains what it receives,
whether solid or liquid, till it is altered and digested. It sometimes
contracts, sometimes dilates. It blends and mixes the food together, so
that it is easily concocted and digested by its force of heat, and by
the animal spirits is distributed into the other parts of the body.
LV. As to the lungs, they are of a soft and spongy substance, which
renders them the most commodious for respiration; they alternately
dilate and contract to receive and return the air, that what is the
chief animal sustenance may be always fresh. The juice,[234] by which
we are nourished, being separated from the rest of the food, passes the
stomach and intestines to the liver, through open and direct passages,
which lead from the mesentery to the gates of the liver (for so they
call those vessels at the entrance of it). There are other passages
from thence, through which the food has its course when it has passed
the liver. When the bile, and those humors which proceed from the
kidneys, are separated from the food, the remaining part turns to
blood, and flows to those vessels at the entrance of the liver to which
all the passages adjoin. The chyle, being conveyed from this place
through them into the vessel called the hollow vein, is mixed together,
and, being already digested and distilled, passes into the heart; and
from the heart it is communicated through a great number of veins to
every part of the body.
It is not difficult to describe how the gross remains are detruded by
the motion of the intestines, which contract and dilate; but that must
be declined, as too indelicate for discourse. Let us rather explain
that other wonder of nature, the air, which is drawn into the lungs,
receives heat both by that already in and by the coagitation of the
lungs; one part is turned back by respiration, and the other is
received into a place called the ventricle of the heart.[235] There is
another ventricle like it annexed to the heart, into which the blood
flows from the liver through the hollow vein. Thus by one ventricle the
blood is diffused to the extremities through the veins, and by the
other the breath is communicated through the arteries; and there are
such numbers of both dispersed through the whole body that they
manifest a divine art.
Why need I speak of the bones, those supports of the body, whose joints
are so wonderfully contrived for stability, and to render the limbs
complete with regard to motion and to every action of the body? Or need
I mention the nerves, by which the limbs are governed--their many
interweavings, and their proceeding from the heart,[236] from whence,
like the veins and arteries, they have their origin, and are
distributed through the whole corporeal frame?
LVI. To this skill of nature, and this care of providence, so diligent
and so ingenious, many reflections may be added, which show what
valuable things the Deity has bestowed on man. He has made us of a
stature tall and upright, in order that we might behold the heavens,
and so arrive at the knowledge of the Gods; for men are not simply to
dwell here as inhabitants of the earth, but to be, as it were,
spectators of the heavens and the stars, which is a privilege not
granted to any other kind of animated beings. The senses, which are the
interpreters and messengers of things, are placed in the head, as in a
tower, and wonderfully situated for their proper uses; for the eyes,
being in the highest part, have the office of sentinels, in discovering
to us objects; and the ears are conveniently placed in a high part of
the person, being appointed to receive sound, which naturally ascends.
The nostrils have the like situation, because all scent likewise
ascends; and they have, with great reason, a near vicinity to the
mouth, because they assist us in judging of meat and drink. The taste,
which is to distinguish the quality of what we take; is in that part of
the mouth where nature has laid open a passage for what we eat and
drink. But the touch is equally diffused through the whole body, that
we may not receive any blows, or the too rigid attacks of cold and
heat, without feeling them. And as in building the architect averts
from the eyes and nose of the master those things which must
necessarily be offensive, so has nature removed far from our senses
what is of the same kind in the human body.
LVII. What artificer but nature, whose direction is incomparable, could
have exhibited so much ingenuity in the formation of the senses? In the
first place, she has covered and invested the eyes with the finest
membranes, which she hath made transparent, that we may see through
them, and firm in their texture, to preserve the eyes. She has made
them slippery and movable, that they might avoid what would offend
them, and easily direct the sight wherever they will. The actual organ
of sight, which is called the pupil, is so small that it can easily
shun whatever might be hurtful to it. The eyelids, which are their
coverings, are soft and smooth, that they may not injure the eyes; and
are made to shut at the apprehension of any accident, or to open at
pleasure; and these movements nature has ordained to be made in an
instant: they are fortified with a sort of palisade of hairs, to keep