The anatomical gulf between men and apes does not exist. There are,
in fact, no gulfs anywhere, only gradations. All chasms are
completely covered by unmistakable affinities, in spite of the fact
that the remains of so many millions of deceased races lie hidden
beneath seas or everlastingly locked in the limy bosoms of the
continents. There are closer kinships and remoter kinships, but
there are kinships everywhere. The more intimate kinships are
indicated by more definite and detailed similarities, and the more
general relationships by more fundamental resemblances. All
creatures are bound to all other creatures by the ties of a varying
but undeniable consanguinity.
Man stands unquestionably in the primate order of animals, because
he has certain qualities of structure which all primates have, and
which all other animals have not: hands and arms and nails, a
bagpipe stomach, great subordination of the cerebellum, a disc-like
placenta, teeth differentiated into incisors, canines, and molars,
and pectoral milk glands.
Man is more closely akin to the anthropoid apes than to the other
primates on account of his immense brain, his ape-like face, his
vertical spine, and in being a true two-handed biped. The manlike
apes and men have the same number and kinds of teeth, the same limb
bones and muscles, like ribs and vertebrae, an atrophied tail, the
same brain structure, and a suspicious similarity in looks and
disposition. Men and anthropoids live about the same number of
years, both being toothless and wrinkled in old age. The beard, too,
in both classes of animals appears at the same period of life and
obeys the same law of variation in colour. Even the hairs on
different parts of the bodies of men and anthropoids, as on the
arms, incline at a like angle to the body surface. The hair on the
upper arm and that on the forearm, in both anthropoids and men,
point in opposite directions—toward the elbow. This peculiarity is
found nowhere in the animal kingdom excepting in a few American
monkeys.
Man’s mammalian affinities are shown in his diaphragm, his hair,
his four-chambered heart, his _corpus callosum_, his non-nucleated
blood-corpuscles, and his awkward incubation.
The fishes, frogs, reptiles, birds, and non-human mammals are human
in having two body cavities, segmented internal skeletons, two pairs
of limbs, skulls and spinal columns, red blood, brains, and dorsal
cords; and in possessing two eyes, two ears, nostrils, and mouth
opening out of the head. And finally all animals, including man, are
related to all other animal forms by the great underlying facts of
their origin, structure, composition, and destiny. All creatures,
whether they live in the sea, in the heavens, or in subterranean
glooms; whether they swim, fly, crawl, or walk; whether their world
is a planet or a water-drop; and whether they realise it or not,
commence existence in the same way, are composed of the same
substances, are nourished by the same matters, follow fundamentally
the same occupations, all do under the circumstances the best they
can, and all arrive ultimately at the same pitiful end.