Instinct has been defined as a spontaneous impulse, especially in the
lower animals—that moves them, without reasoning, toward actions that
are essential to their existence, preservation and development.
Instinct, imbedded in their organic structure, is the guide of animal
life as reason is the guide of rational life. Instinct is said to be
incapable of development and progress.
It is instinct that guides the wild goose in his long flight to meet the
changing requirements of food and nesting. It is instinct that enables
the carrier pigeon, though taken hoodwinked and by night to distant
points, to wing his way unerringly homeward. Instinct leads the thrifty
squirrel to stock his larder with nuts in anticipation of the period
that must pass ere nuts are ripe again, and teaches him to destroy the
embryo plant by biting out the germ so that his chestnuts will not
sprout and thus be spoiled for food. The same wonderful power enables
the bee to build her comb upon the strictest mathematical principles so
as to obtain the greatest storage capacity and strength of structure
with smallest consumption of wax, and then to store it with one of the
most perfect and concentrated of foods. These and many other well-known
cases of animal instinct will occur to the reader, but the object of
this article is to mention a few phenomena of plant life, whereby they
make, what we should designate in human beings, an intelligent
adjustment to environment or provision for their future life and
development.
As autumn approaches, even before Jack Frost strikes the first rude
signal for winter quarters for insect and plant, or the wintry blasts
compel the trees to furl sail and scud under bare poles, the forest
trees begin to prepare for unfavorable conditions by forming and
securely tucking away the bud that is next year to develop into leaf and
flower. Before the leaf drops off, a substantial layer of cork is made
to close up the pores through which the sap had so freely flowed during
the growing season.
My older readers know, of course, that the green color of the leaf is
due to the numerous corpuscles of chlorophyll which fill the cells. This
same chlorophyll has an important mission to fulfill. These little green
bodies are the only real food-making machines in nature. Upon the
product of these tiny mills all animate nature depends for food. Their
motive power is light, and their raw material the inorganic fluids
absorbed by the roots from the soil, and their product is sugars and
starches. It will be seen that chlorophyll is one of the most precious,
as well as one of the rarest of substances, for while there may appear a
great quantity it is superficial, never entering deeply into the
substance of the plant.
The trees, by a sort of instinct, shall we say, withdraw their cohorts
of green-liveried workers from the front as autumn approaches and deck
themselves in the more gaudy but less wholesome colors of declining
life. It is after the chlorophyll is withdrawn that the layer of cork is
formed. The sturdy oak usually holds his brown leaves until they are
whipped off by the wind.
The plants have been using light as a motive power for ages, while man,
with his much-vaunted reason, is just beginning to utilize the kindred
force, electricity, in arts and sciences. Man makes light draw a few
pictures in sombre black and white, while nature flings broadcast
landscape and life scenes in varied tints and shades.
In the process of photosynthesis much more energy is received than is
necessary to run the machinery, so the plant, with commendable
frugality, uses it in laying on what botanists call warming-up colors.
If you will notice the peach twigs the next time you take a walk, you
will see that the more tender shoots and the buds are decked in rich
reds and browns. That this is not for mere ornament may be practically
demonstrated by wrapping the bulbs of two similar thermometers, the one
with a green leaf, the other with a brown or red leaf, say of begonia or
beet. Then put the two in the sunlight and you will soon find a
difference of from six to ten degrees in favor of the warming-up color.
Speaking of buds, have you examined the horse chestnut bud? It is
prepared for the winter in the most substantial manner. The future leaf
is first wrapped in a quantity of finest silky wool, then a number of
tough light green cases are put on, and this is followed by compact
brown scales neatly overlapping, with a complete coating of wax, so that
the interior is effectively protected from the cold and moisture. The
use of the warming-up colors is quite common with plants.
In the far north the same plant that requires the whole long growing
season to mature its seed, will crowd the whole process into a few
weeks. It will suspend growth and all other processes, or run them on
short time and devote itself almost entirely to producing seed, and the
seed itself will have much thicker shell.
I was interested last autumn in the pathetic struggle of a humble little
Chenopodium album that had started life late and under unfavorable
circumstances. It came up in September under the north piazza near the
beaten foot path; close up to the building. I was first attracted by the
fact that, though it was not over a foot high, it had bloomed and was
making seed at a desperate rate, while its sisters earlier in the season
reached several feet in height before blooming. But, alas! for the
vanity of the poor little creature, the cold weather during the
Christmas holidays came on, and the steam being shut off, the side of
the building grew cold and my struggling little friend was frozen, and
soon its lifeless remains were the sport and derision of the rude
January winds. I pitied the poor little vagabond despite the bad record
of her family. Indeed plants, like people, must suffer sometimes because
of an evil ancestry. In this case I was touched by the pathos of the
situation, and really hoped the pertinacious little wretch might proudly
scatter her well-matured seed upon the hard-beaten path as an
inspiration to the many boys that passed daily, grumbling because of the
hardness of their lot. But the only moral I can now draw is the
foolishness of delaying in the right start.
Sometimes the supply of light-energy is so great that the little
chlorophyll machines cannot use it in their legitimate work, nor does
the plant use it in preparing the warming-up color. Then the disc-shaped
corpuscles turn their edges instead of their flat surfaces to the light,
or sometimes move deeper down into the leaf. In some cases the leaf
itself turns edgewise instead of broadside to the sun.
There are many plants so constituted that they cannot live from year to
year in our northern climate, and they must make some provision for
preserving their species, and right cunningly do they do this. At a
certain period of its growth the potato, for example, puts its
starch-making machinery to work on full time, and hurries the starch
down below the surface of the ground, and stores it up in what we call a
tuber. These tubers have stored in them a number of embryo potato
plants, whose lack-luster eyes we see peeping out on all sides. When the
time for growth comes, the young plant starts with a reserve-food supply
sufficient to keep it growing for some time. We have all noticed, no
doubt, how large a plant will grow from a potato, even in a
comparatively dark cellar. We must not think that tuber-bearing vines
and nut-producing trees are actuated entirely by philanthropic motives.
Each nut is the young tree sent forth with his patrimony strapped to his
back, ready to make a good start in the world as soon as the favorable
time comes.
There are many devices for spending the winter that limits of time and
space will prevent me writing about. Many of them more curious than the
simple examples I have cited.
Plants are themselves generally unable to move from their fixed
positions, so if they are to become prominent in the world they must
send out their children—and many and ingenious are their devices for
accomplishing this end. Most of my readers are familiar with the
parachutes of the silk weed, dandelion and various members of the
Compositae family. How they sail through the air. A walk through the
autumn forests will make one the unconscious, perhaps unwilling, carrier
of numerous Spanish needles, stick tights, burrs and seeds of various
plants who have taught their children to steal rides in all sorts of
provoking ways. I imagine the wicked old mother laughs as her ugly baby
clings to your clothing, sure of a safe ride to a more favorable place
for growing. Many plants achieve the same end in a more pleasant way.
They produce fruits and berries so luscious that some bird or animal
will carry it some distance for the sake of the pulp. Man himself,
philanthropist as he is, when he finds that a plant has produced a
luscious fruit or palatable seed, will help the distribution and growth,
and bring his superior intelligence to the assistance of the plant’s
slow instinct to improve its product. A book might be written upon the
methods of seed dissemination. In fact, there is a very interesting book
upon the subject.
We will just notice briefly the marvelous adaptation of plants to their
environment. In the dry plains of Arizona grows a peculiar thick-leaved,
stunted, cactus-like plant, suited to withstand the drouth. In the
forests of Central South America a great vine climbs to the tops of the
tallest trees and there flaunts its gay colors to the breeze. In Damara
Land, southwest tropical Africa, upon a small upland section, and
nowhere else in the world, grows the marvelous Welwitschia mirabilis,
with no real leaves, but with its two cotyledons, persistent and growing
to enormous length, living a century and acquiring a great trunk, the
flower-stalk growing up from the bare trunk while the two great leaves,
if I may so designate them, whip about in the breezes for a century
without change, except as they fray out at the ends. These three so
dissimilar plants all had a common, not so remote, ancestor, but have
grown so unlike in their effort to adapt themselves to their
environment, that no casual observer would suspect they were akin.
There is so much to say about the wonderful intelligence displayed by
plants in their various activities, that a volume could not do the
subject justice. We started with the question, Do plants have instinct?
We end with the question, Have they?
Rowland Watts.
Still winter holds the frozen ground and fast the streams with ice are
bound,
There’s many a dreary week to come before the flowers bloom;
Though everything were lost in snow yet Nature’s heart beats warm
below
And Spring will build her palace gay on hoary Winter’s tomb.
—George Gee.
[Illustration: ]
THE DOVEKIE.
(_Alle alle._)
This little bird, often called the Sea Dove, belongs to the family of
auks (Alcidæ). The range of the Dovekie is quite limited. While the
marble murrelet, a related bird, is confined to the northern Pacific
coast of North America, this little bird frequents only the “coast and
islands of the north Atlantic and eastern Arctic Oceans; in North
America south in winter to New Jersey.” It breeds only in the northern
part of its range. It has been observed as far west as the state of
Michigan, but its appearance there was, without doubt, accidental, for
it prefers the wild sea coast, where the storm and waves bring to it an
abundant supply of food.
It is said to be a rare visitor on the coasts of the British Islands and
it has been reported as common as far to the northward as Spitzbergen.
In Greenland, where it is commonly found a close companion of the
black-billed auk, the native Greenlanders call the Dovekie the Ice Bird,
as they consider it a harbinger of ice.
Though the wings of the Dovekie are small in proportion to the size of
its body it flies well and rapidly. One writer states that it will move
its wings almost as rapidly as will a humming-bird. It is an expert
diver and while swimming or resting on the water it will frequently dip
its bill into the water. On the land it is much more graceful and walks
better than nearly all the other members of the family of auks.
It feeds chiefly on small fish, crustacea and mollusks and will become
very fat during a prolonged stormy season when the waves wash up an
abundant supply of crabs and fish.
The Dovekie builds a simple nest usually in the crevices of rocky cliffs
bordering the sea coast. It lays one or two bluish white eggs which are
about the size of the pigeon’s.
Mr. Saunders in speaking of the habits of the Dovekie says: “On the
approach of a vessel this bird has a peculiar way of splashing along the
surface of the water, as if unable to fly, and then diving through the
crest of an advancing wave; it swims rather deep and very much by the
stern.”
The Dovekie is sometimes called a little auk to distinguish it from the
larger species of the family. The flightless great auk, which at one
time was common along the north Atlantic coast, belongs to this family.
No living representative of the great auk has been reported since the
year 1842. Unable to protect itself by flight it was ruthlessly
exterminated by the zeal of hunters and fishermen who sought it for
food, for its feathers and for the oil that could be extracted from its
flesh.
As flying ever westward Night’s shadows swiftly glide,
The sunrise at the dawning illumes the countryside.
The stars in quick succession in ether melt away,
Until the brightest planet is lost in glowing day.
—George Gee.