If we figure to ourselves the geologic history of the earth under
the symbol of a year of three hundred and sixty-five days, each day
a million years, which is probably not far out of the way, then man,
the biped, the Homo sapiens, in relation to this immense past, is of
to-day, or of this very morning; while the origin of the first
vertebrates, the fishes, from which he has arisen, falls nearer the
middle of the great year. Or, dividing this geologic year into four
divisions or seasons, primary, secondary, tertiary, and quaternary,
the fishes fall in the primary, the reptiles in the secondary, the
mammals in the tertiary, and man in the early quaternary.
If the fluid earth hardened, and the seas were formed in the first
month of this year, then probably the first beginning of life
appeared in the second month, the invertebrate in the third or
fourth,--March or April,--the vertebrates in May or June, the
amphibians in July or August, the reptiles in August or September,
the mammals in October or November, and man in December,--separated
from the first beginnings of life by all those millions upon
millions of years.
If life is a ferment, as we are told it is, how long it took this
yeast to leaven the whole loaf! Man is evidently the end of the
series, he is the top of the biological tree. His specialization
upon physical lines seems to have ended far back in geologic time;
his future specialization and development is evidently to be upon
mental and spiritual lines. Nature, as I have said, began to tend
more and more to brains in the early Tertiary,--the autumn of the
great year; her best harvest began to mature then, her grain began
to ripen. Indeed, this increased cephalization of animal life in the
fall of the great year does suggest a kind of ripening process, the
turning of the sap and milk, which had been so abundant and so
riotous in the earlier period, into fibre and fruit and seed.
May it not be that that long and sultry spring and summer of the
earth's early history, a time probably longer than has since
elapsed, played a part in the development of life analogous to that
played by our spring and summer, making it opulent, varied,
gigantic, and making possible the condensation and refinement that
came with man in the recent period?
The earth is a pretty big apple, and the solar tree upon which it
hangs is a pretty big tree, but why may it not have gone through a
kind of ripening process for all that? its elements becoming less
crude and acrid, and better suited to sustain the higher forms, as
the eons passed?
At any rate, the results seem to justify such a fancy. The earth has
slowly undergone a change that may fairly be called a ripening
process; its soil has deepened and mellowed, its harsher features
have softened, more and more color has come to its surface, the
flowers have bloomed, the more succulent fruits have developed, the
air has cleared, and love and benevolence and altruism have been
born in the world.
V
Life had to creep or swim long before it could walk, and it walked
long before it could fly; it had feeling long before it had eyes,
and it no doubt had eyes long before it could hear or smell. It was
capable of motion long before it had limbs; it assimilated food long
before it had a mouth or a stomach. It had a digestive tract long
before it had a spinal cord; it had nerve ganglia long before it had
a well-defined brain. It had sensation long before it had
perception; it was unisexual long before it was bisexual; it had a
shell long before it had a skeleton; it had instinct and reflex
action long before it had self-consciousness and reason. Always from
the lower to the higher, from the simple to the more complex, and
always slowly, gently.
Life has had its foetal stage, its stage of infancy, and childhood,
and maturity, and will doubtless have its old age. It took it
millions upon millions of years to get out of the sea upon dry land;
and it took it more millions upon dry land, or since the
Carboniferous age, when the air probably first began to be
breathable,--all the vast stretch of the Secondary and Tertiary
ages,--to get upright and develop a reasoning brain, and reach the
estate of man. Step by step, in orderly succession, does creation
move. In the rising and in the setting of the sun one may see how
nature's great processes steal upon us, silently and unnoticed, yet
always in sequence, stage succeeding stage, one thing following from
another, the spectacular moment of sunset following inevitably from
the quiet, unnoticed sinking of the sun in the west, or the
startling flash of his rim above the eastern horizon only the
fulfillment of the promise of the dawn. All is development and
succession, and man is but the sunrise of the dawn of life in
Cambrian or Silurian times, and is linked to that time as one hour
of the day is linked to another.
The more complex life became, the more rapidly it seems to have
developed, till it finally makes rapid strides to reach man. One
seems to see Life, like a traveler on the road, going faster and
faster as it nears its goal. Those long ages of unicellular life in
the old seas, how immense they appear to have been; then how the age
of invertebrates dragged on, millions upon millions of years; then
the age of fishes; the Palaeozoic age, how vast--put by Haeckel at
thirty-four millions of years, adding rock strata forty-one thousand
feet thick; then the Mesozoic or third period, the age of reptiles,
eleven million years, with strata twelve thousand feet thick. Then
came the Caenozoic age, or age of mammals, three million years, with
strata thirty-one hundred feet thick. The god of life was getting in
a hurry now; man was not far off. A new device, the placenta, was
hit upon in this age, and probably the diaphragm and the brain of
animals, all greatly enlarged. Finally comes the Anthropozoic or
Quaternary age, the age of man, three hundred thousand years, with
not much addition to the sedimentary rocks.
Man seems to be the net result of it all, of all these vast cycles
of Palaeozoic, Mesozoic, and Caenozoic life. He is the one drop
finally distilled from the vast weltering sea of lower organic
forms. It looks as if it all had to be before he could be--all the
delay and waste and struggle and pain--all that long carnival of sea
life, all that saturnalia of gigantic forms upon the land and in the
air, all that rising and sinking of the continents, and all that
shoveling to and fro and mixing of the soils, before the world was
ready for him.
In the early Tertiary, millions of years ago, the earth seems to
have been ripe for man. The fruits and vegetables and the forest
trees were much as we know them, the animals that have been most
serviceable to us were here, spring and summer and fall and winter
came and went, evidently birds sang, insects hummed, flowers
bloomed, fruits and grains and nuts ripened, and yet man as man was
not.
Under the city of London is a vast deposit of clay in which
thousands of specimens of fossil fruit have been found like our
date, cocoanut, areca, custard-apple, gourd, melon, coffee, bean,
pepper, and cotton plant, but no sign of man. Why was his
development so tardy? What animal profited by this rich vegetable
life? The hope and promise of the human species at that time
probably slept in some lowly marsupial. Man has gathered up into
himself, as he traveled his devious way, all the best powers of the
animal kingdom he has passed through. His brain supplies him with
all that his body lacks, and more. His specialization is in this
highly developed organ. It is this that separates him so widely from
all other animals.
Man has no wings, and yet he can soar above the clouds; he is not
swift of foot, and yet he can out-speed the fleetest hound or horse;
he has but feeble weapons in his organization, and yet he can slay
or master all the great beasts; his eye is not so sharp as that of
the eagle or the vulture, and yet he can see into the farthest
depths of siderial space; he has only very feeble occult powers of
communication with his fellows, and yet he can talk around the world
and send his voice across mountains and deserts; his hands are weak
things beside a lion's paw or an elephant's trunk, and yet he can
move mountains and stay rivers and set bounds to the wildest seas.
His dog can out-smell him and out-run him and out-bite him, and yet
his dog looks up to him as to a god. He has erring reason in place
of unerring instinct, and yet he has changed the face of the planet.
Without the specialization of the lower animals,--their wonderful
adaptation to particular ends,--their tools, their weapons, their
strength, their speed, man yet makes them all his servants. His
brain is more than a match for all the special advantages nature has
given them. The one gift of reason makes him supreme in the world.