It was in the zoology class at college. We had made all the long
journey from amoeba to coral, from coral to worm, from worm to
mollusk, from mollusk to fish, from fish to reptile, and from
reptile to mammal—and there, in the closing pages of faithful old
Packard, we found it. ‘A mammal of the order of primates,’ the
book said, with that unconcern characteristic of the deliverances of
science. I was almost saddened. It was the first intimation I had
ever received of that trite but neglected truth that _man is an
animal_.
But the intimation was so weak, and I was at that time so
unconscious, that it was not till years later that I began, through
reflection, actually to realise the truth here first caught sight
of. During these years I knew that man was not a mineral nor a
plant—that, indeed, he belonged to the animal kingdom. But, like
most men still, I continued to think of him as being altogether
different from other animals. I thought of man _and the animals_,
_not_ of man and the _other_ animals. Man was somehow _sui generis_.
He had had, I believed, a unique and miraculous origin; for I had
not yet learned of organic evolution. The pre-Darwinian belief that
I had come down from the skies, and that non-human creatures of all
kinds had been brought into existence as adjuncts of the
distinguished species to which I belonged, occupied prominent place
in my thinking. Non-human races, so I had been taught, had in
themselves no reason for existence. They were accessories. A chasm,
too wide for any bridge ever to span, yawned between the human and
all other species. Man was celestial, a blue-blood barely escaping
divinity. All other beings were little higher than clods. So
faithfully and mechanically did I reflect the bias in which I had
grown up.
But man _is_ an _animal_. It was away out there on the prairies,
among the green corn rows, one beautiful June morning—a long time
ago it seems to me now—that this revelation really came to me. And
I repeat it here, as it has grown to seem to me, for the sake of a
world which is so wise in many things, but so darkened and wayward
regarding this one thing. However averse to accepting it we may be
on account of favourite traditions, man is an animal in the most
literal and materialistic meaning of the word. Man has not a spark
of so-called ‘divinity’ about him. In important respects he is
the most highly evolved of animals; but in origin, disposition, and
form he is no more ‘divine’ than the dog who laps his sores, the
terrapin who waddles over the earth in a carapace, or the
unfastidious worm who dines on the dust of his feet. Man is not the
pedestalled individual pictured by his imagination—a being
glittering with prerogatives, and towering apart from and above all
other beings. He is a pain-shunning, pleasure-seeking,
death-dreading organism, differing in particulars, but not in kind,
from the pain-shunning, pleasure-seeking, death-dreading organisms
below and around him. Man is neither a rock, a vegetable, nor a
deity. He belongs to the same class of existences, and has been
brought into existence by the same evolutional processes, as the
horse, the toad that hops in his garden, the firefly that lights its
twilight torch, and the bivalve that reluctantly feeds him.
Man’s body is composed fundamentally of the same materials as the
bodies of all other animals. The bodies of all animals are composed
of clay. They are formed of the same elements as those that murmur
in the waters, gallop in the winds, and constitute the substance of
the insensate rocks and soils. More than two-thirds of the weight of
the human body is made up of oxygen alone, a gas which forms
one-fifth of the weight of the air, more than eight-ninths of that
of the sea, and forty-seven per cent, of the superficial solids of
the earth.
Man’s body is composed of cells. So are the bodies of all other
animals. And the cells in the body of a human being are not
essentially different in composition or structure from the cells in
the body of the sponge. All cells are composed primarily of
protoplasm, a compound of carbon, hydrogen, nitrogen, and oxygen.
Like all other animals, man is incapable of producing a particle of
the essential substance of which his body is made. No animal can
produce protoplasm. This is a power of the plant, and the plant
only. All that any animal can do is to burn the compounds formed in
the sun-lit laboratories of the vegetable world. The human skeleton,
like the skeletons of nearly all other animals, is composed chiefly
of lime—lime being, in the sea, where life spent so many of its
earlier centuries, the most available material for parts whose
purpose it is to furnish shape and durability to the organism. Man
grows from an egg. So do all creatures of clay. Every animal
commences at the same place—in a single, lowly, almost homogeneous
cell. A dog, a frog, a philosopher, and a worm cannot for a long
time after their embryonic commencement be distinguished from each
other. Like the oyster, the ox, the insect, and the fish, like all
that live, move, and breathe, man is mortal. He increases in size
and complexity through an allotted period of time; then, like all
his kindred, wilts back into the indistinguishable flux from which
he came. Man inhales oxygen and exhales carbon dioxide. So does
every animal that breathes, whether it breathe by lungs, gills,
skin, or ectosarc, and whether it breathe the sunless ooze of the
sea floor or the ethereal blue of the sky. Animals inhale oxygen
because they eat carbon and hydrogen. The energy of all animals is
produced mainly by the union of oxygen with the elements of carbon
and hydrogen in the tissues of animal bodies, the plentiful and
ardent oxygen being the most available supporter of the combustion
of these two elements.
Man is, then, an animal, more highly evolved than the most of his
fellow-beings, but positively of the same clay, and of the same
fundamental make-up, with the same eagerness to exceed and the same
destiny, as his less pompous kindred who float and frolic and pass
away in the seas and atmospheres, and creep over the land-patches of
a common clod.