IV

How often it turns out that a man's minor works outlive his major!

This is true in both literature and science, but more often in the

former than in the latter. Darwin furnishes a case in the field of

science. He evidently looked upon his "Origin of Species" as his great

contribution to biological science; but it is highly probable that his

"Voyage of the Beagle" will outlast all his other books. The "Voyage"

is of perennial interest and finds new readers in each generation. I

find myself re-reading it every eight or ten years. I have lately read

it for the fourth time. It is not an argument or a polemic; it is a

personal narrative of a disinterested yet keen observer, and is

always fresh and satisfying. For the first time we see a comparatively

unknown country like South America through the eyes of a born and

trained naturalist. It is the one book of his that makes a wide appeal

and touches life and nature the most closely.

We may say that Darwin was a Darwinian from the first,--a naturalist

and a philosopher combined,--and was predisposed to look at animate

nature in the way his works have since made us familiar with.

In his trip on the Beagle he saw from the start with the eyes of a

born evolutionist. In South America he saw the fossil remains of the

Toxodon, and observed, "How wonderful are the different orders, at the

present time so well separated, blended together in the different

points of the structure of the Toxodon!" All forms of life attracted

him. He looked into the brine-pans of Lymington and found that water

with one quarter of a pound of salt to the pint was inhabited, and he

was led to say: "Well may we affirm that every part of the world is

habitable! Whether lakes of brine or those subterranean ones hidden

beneath volcanic mountains,--warm mineral springs,--the wide expanse

and depth of the ocean,--the upper regions of the atmosphere, and even

the surface of perpetual snow,--all support organic beings."

He studies the parasitical habit of the cuckoo and hits on an

explanation of it. He speculates why the partridges and deer in South

America are so tame.

His "Voyage of the Beagle" alone would insure him lasting fame. It is

a classic among scientific books of travel. Here is a traveler of a

new kind: a natural-history voyager, a man bent on seeing and taking

note of everything going on in nature about him, in the non-human, as

well as in the human world. The minuteness of his observation and the

significance of its subject-matter are a lesson to all observers.

Darwin's interests are so varied and genuine. One sees in this volume

the seed-bed of much of his subsequent work. He was quite a young man

(twenty-four) when he made this voyage; he was ill more than half the

time; he was as yet only an observer and appreciator of Nature, quite

free from any theories about her ways and methods. He says that this

was by far the most important event of his life and determined his

whole career. His theory of descent was already latent in his mind, as

is evinced by an observation he made about the relationship in South

America between the extinct and the living forms. "This relationship,"

he said, "will, I do not doubt, hereafter throw more light on the

appearance of organic beings on our earth, and their disappearance

from it, than any other class of facts."

He looked into the muddy waters of the sea off the coast of Chile, and

found a curious new form of minute life--microscopic animals that

exploded as they swam through the water. In South America he saw an

intimate relationship between the extinct species of ant-eaters,

armadillos, tapirs, peccaries, guanacos, opossums, and so on, and the

living species of these animals; and he adds that the wonderful

relationship in the same continent between the dead and the living

would doubtless hereafter throw more light on the appearance of

organic beings on our earth, and their disappearance from it, than any

other class of facts.

His observation of the evidences of the rise and fall of thousands of

feet of the earth along the Cordilleras leads him to make this rather

startling statement: "Daily it is forced home on the mind of the

geologist that nothing, not even the wind that blows, is so unstable

as the level of the crust of the earth."

There is now and then a twinkle of humor in Darwin's eyes, as when he

says that in the high altitude of the Andes the inhabitants recommend

onions for the "puna," or shortness of breath, but that he found

nothing so good as fossil shells.

Water boils at such a low temperature in the high Andes that potatoes

will not cook if boiled all night. Darwin heard his guides discussing

the cause. "They had come to the simple conclusion that 'the cursed

pot' (which was a new one) did not choose to boil potatoes."

In all Darwin's record we see that the book of nature, which ordinary

travelers barely glance at, he opened and carefully perused.

V

Natural Selection turns out to be of only secondary importance. It is

not creative, but only confirmative. It is a weeding-out process; it

is Nature's way of improving the stock. Its tendency is to make

species more and more hardy and virile. The weak and insufficiently

endowed among all forms tend to drop out. Life to all creatures is

more or less a struggle, a struggle with the environment, with the

inorganic forces,--storm, heat, cold, sterile land, and engulfing

floods,--and it is a struggle with competing forms for food and

shelter and a place in the sun. The strongest, the most amply endowed

with what we call vitality or power to live, win. Species have come to

be what they are through this process. Immunity from disease comes

through this fight for life; and adaptability--through trial and

struggle species adapt themselves, as do our own bodies, to new and

severe conditions. The naturally weak fall by the wayside as in an

army on a forced march.

Every creature becomes the stronger by the opposition it overcomes.

Natural Selection gives speed, where speed is the condition of

safety, strength where strength is the condition, keenness and

quickness of sense-perception where these are demanded. Natural

Selection works upon these attributes and tends to perfect them. Any

group of men or beasts or birds brought under any unusual strain from

cold, hunger, labor, effort, will undergo a weeding-out process.

Populate the land with more animal life than it can support, or with

more vegetable forms than it can sustain, and a weeding-out process

will begin. A fuller measure of vitality, or a certain hardiness and

toughness, will enable some species to hold on longer than others,

and, maybe, keep up the fight till the struggle lessens and victory is

won.

The flame of life is easily blown out in certain forms, and is very

tenacious in others. How unequally the power to resist cold, for

instance, seems to be distributed among plants and trees, and probably

among animals! One spring an unseasonable cold snap in May (mercury

28) killed or withered about one per cent of the leaves on the lilacs,

and one tenth of one per cent of the leaves of our crab-apple tree. In

the woods around Slabsides I observed that nearly half the plants of

Solomon's-seal (_Polygonatum_) and false Solomon's-seal (_Smilacina_)

were withered. The vital power, the power to live, seems stronger in

some plants than in others of the same kind. I suppose this law holds

throughout animate nature. When a strain of any kind comes, these

weaker ones drop out. In reading the stories of Arctic explorers, I

see this process going on among their dog-teams: some have greater

power of endurance than others. A few are constantly dropping out or

falling by the wayside. With an army on a forced march the same thing

happens. In the struggle for existence the weak go to the wall. Of

course the struggle among animals is at least a toughening process. It

seems as if the old Indian legend, that the strength of the foe

overcome passes into the victor, were true. But how a new species

could arrive as the result of such struggle is past finding out.

Variation with all forms of life is more or less constant, but it is

around a given mean. Only those acquired characters are transmitted

that arise from the needs of the organism.

A vast number of changes in plants and animals are superficial and in

no way vital. It is hard to find two leaves of the same tree that will

exactly coincide in all their details; but a difference that was in

some way a decided advantage would tend to be inherited and passed

along. It is said that the rabbits in Australia have developed a

longer and stronger nail on the first toe of each front foot, which

aids them in climbing over the wire fences. The aye-aye has a

specially adapted finger for extracting insects from their

hiding-places. Undoubtedly such things are inherited. The snowshoes

of the partridge and rabbit are inherited. The needs of the organism

influence structure. The spines in the quills in the tails of

woodpeckers, and in the brown creeper, are other cases in point. The

nuthatch has no spines on its tail, because it can move in all

directions, as well with head down as with head up. I have read of a

serpent somewhere that feeds upon eggs. As the serpent has no lips or

distendable cheeks, and as its mechanism of deglutition acts very

slowly, an egg crushed in the mouth would be mostly spilled. So the

eggs are swallowed whole; but in the throat they come in contact with

sharp tooth-like spines, which are not teeth, but downward projections

from the backbone, and which serve to break the shells of the eggs.

Radical or vital variations are rare, and we do not witness them any

more than we witness the birth of a new species. And that is all there

is to Natural Selection. It is a name for a process of elimination

which is constantly going on in animate nature all about us. It is in

no sense creative, it originates nothing, but clinches and toughens

existing forms.

The mutation theory of De Vries is a much more convincing theory of

the origin of species than is Darwin's Natural Selection. If things

would only mutate a little oftener! But they seem very reluctant to do

so. There does seem to have been some mutation among plants,--De

Vries has discovered several such,--but in animal life where are the

mutants? When or where has a new species originated in this way?

Surely not during the historic period.

Fluctuations are in all directions around a center--the mean is always

returned to; but mutations, or the progressive steps in evolution, are

divergent lines away from the center. Fluctuations are superficial and

of little significance; but mutations, if they occur, involve

deep-seated, fundamental factors, factors more or less responsive to

the environment, but not called into being by it. Of the four factors

in the Darwinian formula,--variation, heredity, the struggle, and

natural selection,--variation is the most negligible; it furnishes an

insufficient handle for selection to take hold of. Something more

radical must lead the way to new species.

As applied to species, the fittest to survive is a misleading term.

All are fit to survive from the fact that they do survive. In a world

where, as a rule, the race is to the swift and the battle to the

strong, the slow and the frail also survive because they do not come

in competition with the swift and the strong. Nature mothers all, and

assigns to each its sphere.

The Darwinians are hostile to Lamarck with his inner developing and

perfecting principle, and, by the same token, to Aristotle, who is

the father of the theory. They regard organic evolution as a purely

mechanical process.

Variation can work only upon a variable tendency--an inherent impulse

to development. A rock, a hill, a stream, may change, but it is not

variable in the biological sense: it can never become anything but a

rock, a hill, a stream; but a flower, an egg, a seed, a plant, a baby,

can. What I mean to say is that there must be the primordial tendency

to development which Natural Selection is powerless to beget, and

which it can only speed up or augment. It cannot give the wing to the

seed, or the spring, or the hook; or the feather to the bird; or the

scale to the fish; but it can perfect all these things. The fittest of

its kind does stand the best chance to survive.