question, the extraordinary achievement of synthetic chemistry, of
which Professor Berthelot was the grand master. As long ago as 1828
it was shown that there was at least one exception to the doctrine of
the vitalists, that chemical compounds characteristic of living matter
cannot be built up except by the living organism. To-day chemistry
has succeeded in building up alcohols, starches, sugars, and even the
forerunners of the proteids themselves, from the inorganic elements in
the laboratory, under the action of non-vital forces. This fact could
not be reckoned with a generation ago.
[Sidenote: Can Chemistry Build Up Life?]
We are now entitled to state very briefly the sequence of events
which may reasonably be imagined as culminating in the origin of life
upon the earth _for the first time_. Whatever we may hold as to the
present, we have to recognise that the origin of life for the first
time constituted a fact utterly different in certain essentials from
any origin of life that may be expected to be occurring to-day. The
capital fact is that in the beginning there was no organic matter
to serve as food material. If ever there was a case in which it is
the first step that costs, it is here. Nothing can be easier than
to imagine the spontaneous origin of life in organic matter to-day,
favoured with sun and water and air. The case is far different when a
primary origin in inorganic matter has to be conceived. But of some
things we are certain. We are certain, for instance, that so long as
the earth’s surface temperature was above that of boiling water, no
life was possible. It was not until the gaseous water in the atmosphere
became liquefied by the lowering of the earth’s temperature that the
production of life became possible. The first seas were seas of boiling
water, or rather water infinitesimally below the boiling point, and
we may reasonably suppose, with Buffon, that the Polar seas, being
the first to cool, must have provided the first “nest” for life upon
the earth. I assume, of course, that this essay will be read in
conjunction with that of Professor Sollas upon the formation of the
earth [page 79], and that of Dr. Wallace upon the exquisite adaptation
between life and the earth to-day [page 91].
[Sidenote: The Study of Ferments]
But how were those complex organic bodies formed, especially those
vastly complex proteids with which all life whatsoever, as we know it,
is invariably associated? Apart from the laboratories of the synthetic
chemists of to-day, these compounds are always the products of
pre-existing life, and yet without them there could be no pre-existing
life.
[Sidenote: Mystery of the Cell]
[Sidenote: Is the Cell a Product of Evolution?]
It is my belief that this most difficult question, which quite baffles
us, will seem simple and straightforward in another generation, when
science has devoted itself on a large scale to a study now in its
very infancy--I mean the study of those curious bodies which chemists
call ferments. The properties of ferments are shared both by the
familiar ferments, such as trypsin and pepsin, and also by certain
inorganic substances, such as the metal platinum. Now, though pepsin
is a product of living cells, platinum is certainly not. Altogether
apart from the living world there are substances which have powers of
fermentation; and ferments do not act exclusively, as is erroneously
supposed, in breaking down complex compounds, but also build them
up from their constituents. The powers of a ferment, moreover, are,
so far as we know, inexhaustible. All life whatever is exercised by
ferments, and it is true that life, chemically considered, is “a series
of fermentations.” Now, there is quite recent evidence already which
seems to show that certain ferments, acting in suitable material, have
the power of reproducing themselves--that is to say, of converting that
material into their like. These facts are highly suggestive, and it is
difficult to refrain from suggesting that the gap between living and
lifeless matter, which seemed so absolute to our ancestors, and which
even to us, who have a new conception of matter, seems wide enough, may
yet be bridged by the ferments. We are far too apt, I think, to assume
that when we can see no intermediate stage there were no intermediate
stages, and thus to make difficulties for ourselves. We declare that
life began as a single cell, which was the starting-point of organic
evolution. I myself believe rather that the cell constitutes the acme
of a vast epoch of evolution, which may yet be reproduced in brief in
the laboratory. Denying or declining to think of this, the biologist
who knows the amazing complexity and intricacy of the architecture of
the cell may well decline to believe that such a thing could spring
with a single jump from inorganic matter. We preach and go on preaching
that Nature does nothing by jumps, and in the same breath we declare
that life began as a simple cell. In another hundred years we may begin
to realise that a cell in its own measure and on its own scale is an
organism, as complex and mature a product of evolution as a society,
or, for the matter of that, as the atom of modern chemistry!
But the reader will legitimately declare that so long as the
spontaneous generation of life to-day in the most favourable
circumstances is a proved impossibility, he cannot be expected to
accept the doctrine of its spontaneous origin in the past. There are
signs, however, that the biologists are now beginning to listen to Dr.
Charlton Bastian, the sole survivor from the great controversy of the
’seventies, whose book, “The Evolution of Life,” was published only a
few months ago. Against Pasteur and Tyndall and Huxley, Dr. Bastian
maintained that their experiments, asserted to be conclusive, were not
conclusive--the facts observed were certainly facts, but the deductions
were unwarrantable. The experiments only proved the impossibility under
the experimental conditions. The difference is the difference between
proving what you set out to prove, and begging the whole question.
First establish conditions under which spontaneous generation is
impossible, then demonstrate its non-occurrence under those conditions,
and thence infer that it is impossible under any conditions.
[Sidenote: The Creed of the Future]
The student is right in declining to believe in the spontaneous
beginning of life upon the earth so long as the possibility of
spontaneous generation to-day is denied, but there are not a few who
think that the most conservative attitude that can be adopted is one of
suspended judgment.
The present philosophic tendency is undoubtedly in the direction of a
return to the ancient conception that matter is not without its own
degree of life, and that the distinction between the organic and the
inorganic is a distinction of degree and not radical. Nature does not
admit of being sorted into any of our puny categories. As the facts
accumulate they point more and more definitely towards the opinion that
hylozoism, or the doctrine of potential life in all matter, will be
part of the scientific creed of the future.
Controversies as to the origin of life, judged in the light of this
great conception, seem to become trivial if not puerile. Knowing,
as we now do, that Plato’s conception of matter was as false as it
possibly could be, and having had revealed to us by radio-activity the
omnipresence within the very atoms of matter, of forces incessant and
stupendous, we find the doctrine of vitalism, however stated, to be
wholly meaningless; we find that the gap between the living and the
lifeless is by no means abysmal or impassable.
[Sidenote: How Long Has Life Existed?]
And the definition of life as self-movement seems to become almost
comical, for on that definition surely the whole physical universe,
the only perpetual motion machine we know of, is itself alive. A
discussion of this question can at the utmost only be suggestive. Very
few positive assertions have been made, nor can their number be added
to, in reference to a question which is bound to be asked: How long has
life existed on the earth? The study of radium and its presence in the
earth’s crust alone suffices to abolish altogether the old estimates,
and new ones cannot yet be substituted. Only it is certain that the
past history of planetary life may be far longer than any previous
estimate has indicated. It now seems that the earth is not only not
self-cooling, but actually self-heating, and if on the older assumption
Lord Kelvin could talk of a hundred million years since, so to speak,
water first became wet, and life, as we know it, possible, who shall
say of how long periods we may speculate now? Meanwhile, the glass-eyed
stare vacantly around them and declare that the progress of science
means the destruction of the spirit of wonder and reverence. To them we
reply in the words of the Earth Spirit in Goethe’s “Faust”:
“At the whirring loom of Time unawed,
I weave the living garment of God.”
C. W. SALEEBY
[Illustration:
THE MASTERY OF THE EARTH AND HOW MAN OBTAINED IT
BY DR. ARCHDALL REID]
All the world--at any rate, all that part of the world which is
acquainted with the facts--is now agreed that man is a product of
evolution, and that his remote ancestors were of different bodily make
and shape, and of different mental type and calibre, from their late
descendants. No study of human kind can be comprehensive that does not
include a survey of the mode by which the faculties that have given man
the mastery of the earth were evolved.
[Sidenote: We Know the Present by the Past]
A history of his evolution, based, like a political history, on
episodes, cannot, of course, be written. But man is a bundle of parts
and capabilities. By comparing the civilised being with the savage and
the savage with lower animals, we are able to trace, in many important
particulars at least, his natural history with a degree of certainty to
which, I think, no political history can aspire. As our comprehension
of adult man is helped by a knowledge of the development of the child,
so our understanding of our species is aided by a study of its past.
Armed with some clear conceptions of what man was, and is, we shall
be the better fitted to investigate social and political change, and
to perceive how it happens that while some nations have inherited the
earth and the fruits thereof, others have stagnated or fallen into
decay.
[Sidenote: How Man Learns by Experience]
At a certain stage in his development the caterpillar builds himself
a cocoon. His dwelling is a wonderful structure, but from our human
point of view the remarkable thing is that he does not learn to build
it. He may never have seen a cocoon before, and he constructs only
one in his life. Yet his work is perfect, or at least very excellent,
and it is as good in its beginnings as in its endings. Evidently he
owes nothing to experience, but is impelled and guided throughout by
a faculty which we term _instinct_. An instinct may be defined as an
innate, inherited impulse, an inclination to do a certain definite
act, the instinctive act, on receipt of a certain definite stimulus
or incitement to action. In the case of the caterpillar the stimulus
appears to be the sight at the proper time of a suitable spot in which
to build a cocoon. Since this particular impulse does not appear at the
beginning of conscious life, it is termed a deferred instinct. Man,
on the other hand, cannot build his house unless he first learns how
to build. He depends, not on instinct, but on experience. The faculty
by means of which experience is stored in the mind is _memory_. The
faculty by means of which we use stored experience to guide present
or future conduct is _intelligence_. When the contents of memory are
very vast, and the processes of thought by which they are utilised
comparatively difficult and complex, intelligence is termed _reason_.
Intelligence and reason depend, therefore, on memory, on ability to
learn, on capacity to profit by experience. Memory is not the whole of
intelligence, but it is the basis of it. Without memory there could be
feeling and emotion, but no thought, for the materials of thought would
be lacking.
[Sidenote: Instinct in Place of Memory]
[Sidenote: The Basis of Rational Action]
We always measure the intelligence of an animal by its power of
profiting by experience. Thus, a cat is more intelligent than a rabbit
because it can learn more; a dog, for the same reason, is still more
intelligent. A purely instinctive animal, one that has no memory, can
have no conception of its past, and therefore no idea of its future.
It lives wholly in the immediate present; feeling, but not thinking.
It acts entirely on inclination, not on reflection. It makes provision
for the future, not with any notion of providing, but simply because
it has an impulse to a certain course of action, the performance of
which gives it pleasure of the kind a child derives from playing or
eating, and with the ultimate result of which it is no more consciously
concerned than a child. If a caterpillar sheltered in a hole with the
idea, founded on past experience, of avoiding danger, his action would
be intelligent. If, appealing to a memory in which a great number of
complex experiences were stored, he took thought and designed himself
a shelter in which provision was made for all sorts of _remembered_
dangers, his action would be rational. But if, making no appeal to the
past nor taking thought for the future, he builds only because impelled
by an innate impulse, then, no matter how elaborate the edifice he
rears, his action is instinctive.
Animals low in the scale of life--for example, most insects--appear
incapable of learning. But often they are wonderfully equipped by
instinct. The details of the behaviour of a small beetle, as quoted
from Professor Lloyd Morgan, may not have been quite correctly
ascertained, but they are sufficiently accurate for our purpose.
A certain beetle (Sitaris) lays its eggs at the entrance of the
galleries excavated by a kind of bee (Anthophora), each gallery
leading to a cell. The young larvæ are hatched as active little
insects, with six legs, two long antennæ, and four eyes, very
different from the larvæ of other beetles. They emerge from the egg
in the autumn, and remain in a sluggish condition till the spring.
At that time (in April) the drones of the bee emerge from the
pupæ, and as they pass out through the gallery the Sitaris larvæ
fasten upon them. There they remain till the nuptial flight of
the Anthophora, when the larva passes from the male to the female
bee. Then again they wait their chance. The moment the bee lays an
egg, the Sitaris larva springs upon it. Even while the poor mother
is carefully fastening up her cell, her mortal enemy is beginning
to devour her offspring, for the egg of the Anthophora serves not
only as a raft, but as a repast. The honey, which is enough for
either, would be too little for both, and the Sitaris, therefore,
at its first meal, relieves itself from its only rival. After
eight days the egg is consumed, and on the empty shell the Sitaris
undergoes its first transformation, and makes its appearance in a
very different form.... It changes into a white, fleshy grub, so
organised as to float on the surface of the honey, with the mouth
beneath and the spiracles above the surface.... In this state
it remains until the honey is consumed, and, after some further
metamorphoses, develops into a perfect beetle in August.
[Sidenote: Wonderful Instinct of the Beetle]
The beetle has sense organs; therefore she feels. But we have no reason
to suppose that she remembers or thinks. Memory would be of little use
to her; therefore parsimonious Nature bestows little or none. Cast
adrift in a hostile world, she must come into existence ready armed by
instinct for the battle of life. She has no time to learn, and during
the rapid and strange changes in her career has little opportunity of
acquiring knowledge that could beneficially guide her future conduct.
Since memory and its corollary reflection are most developed in the
highest animals, and are imperceptible in the lower, they are clearly
later and higher products of evolution than instinct.
[Sidenote: Man’s Helplessness at Birth]
Family life is a product of memory, for the mate and offspring are
_re_-cognised; therefore it always implies some degree of intelligence.
The young are watched and protected, and taught by the higher animals.
Opportunities are thus afforded of learning about the world, and more
particularly of acquiring the traditions, the stored experiences,
of the race. With the opportunity to profit by experience comes the
ability to profit by it, and with the latter a gradual decay of
instinct. Intelligence is substituted, more or less, for unthinking
impulse. All the instincts are not lost, but in the higher animals we
find no such elaborate innate impulses as in the lower. “Sitaris” is
able to fend for herself from the first; but just in proportion as
animals are highly placed in the scale of life, so they are helpless
at the beginnings of consciousness, but correspondingly capable later.
A young pig can run as soon as it is born, but the acquirements of the
most learned pig are small compared to that of a dog, which, though
more helpless than the pig at birth, is so teachable that he becomes
the companion of man. Our domestic animals are all teachable, otherwise
we could not tame them.
Of living beings man is by far the most helpless at birth. He cannot
even seek the breast. In him instinct is at its minimum. For him more
than any other animal prolonged and elaborate tuition is necessary;
but so vast is his memory, and so great his power of utilising its
stored experience, that in later life he is beyond comparison the most
capable of the inhabitants of the earth. Compare what even a dull
man knows, including the words of a language and its inflections and
articulations, with what is acquired by the cleverest dog, and the
immensity of the difference is at once apparent. We may take a solitary
frog and rear him from the egg in an aquarium. If, subsequently, we
remove him to a pond, he will take his place with his fellows at
once. He has little, if anything, to learn. Instinctively he knows his
food, and how to seek it; his enemies and rivals, and how to escape or
fight them; his mate, and how to deal with her; and she knows how to
dispose of her eggs. But how forlorn and helpless would be a man reared
from infancy in a dark cell out of sight and sound of his kind, and
then turned into a world where his _experienced_ fellows struggle for
existence!
[Sidenote: Fear is the Result of Experience]
Traditional knowledge--knowledge, that is, imparted by one generation
to the next--is common enough amongst the higher of the lower animals,
and forms no inconsiderable part of their mental equipment. Thus we
may see the hen teaching her chickens how to seek food, and the cat
instructing her kitten how to ambush mice. Birds and mammals inhabiting
desert islands have none of that fear of man which in our country they
acquire from dire experience. We have a saying, “as wild as a hawk”;
but Darwin relates how he almost pushed a hawk from its perch with
his gun in the Galapagos Islands. Round our coasts the sea-birds are
exceedingly shy; in a harbor they feed from the hand. Formerly the
Arctic seals, impelled by fear of bears, inhabited the outer margin
of the floes; at the present day they have retreated from the more
dangerous neighbourhood of man to the landward edge. Antarctic seals,
harried by the great carnivora of the ocean, are watchful in the water;
on land or on the surface of the ice, where till lately they met no
danger, they may be slaughtered like sheep in a shambles. They are
capable of profiting by experience; but they are slow to learn, and
can acquire but little. Judged by our human standard, they are very
stupid. The means of escape adopted by Arctic seals, and the means of
capturing them, the ships and guns adopted by man, furnish a measure of
the intellectual difference.
[Sidenote: Slavery in the World of Insects]
When animals are social, and so have the opportunity of learning, not
only from their parents, but from other members of the species, the
power of making useful mental acquirements is correspondingly great. It
reaches a remarkable degree of development even amongst insects, some
species of which live together in great communities. Young ants, for
example, are tended with anxious care. It is said that they are led
about the nest and instructed by older individuals. They are reported
to be playful. Most significant of all is the fact that some species
have the habit of capturing slaves belonging to other species, which
they take as pupæ, never as adult ants, and to whom, as they develop,
they teach their duties. The slaves are neuter individuals, and have no
offspring, the supply being maintained by fresh captures. It follows
that the slaves must _learn_ their work, and therefore that their
performance of it is not instinctive, but intelligent.
It is a fair inference that many of the so-called instincts of ants
are really acquired habits, bits of knowledge and ways of thinking
and acting which are handed down from one generation to the next, not
by actual inheritance, but traditionally and educationally, just as
children receive from us language, or religion, or a trade. Indeed,
there is reason to believe that the power of making mental acquirements
has evolved to a greater degree in the favourable environment of the
ant-nest than among any other species except man.
[Sidenote: Man’s Essential Instincts]
The instincts of man, though comparatively few and simple, are yet
essential to his existence. He has the instinct of hunger and the
instinctive recognition of food as food, the instincts to sleep
periodically, to rest when tired, and to sport when rested, the
instincts of curiosity and imitativeness, and the deferred instincts
of sexual and parental love, and perhaps one or two others. All these
innate impulses he shares with the lower animals, but those which impel
him to store and use his vaster memory are more developed in him than
in any other type. Thus the instinct of sport urges him, not only to
develop his limbs, but, through experience, to acquire dexterity and
much besides. The little girl turns naturally to her doll, which she
handles as she will her baby. The play of a boy as naturally involves
contests, which foreshadow the grimmer battles of adult life. As he
grows older the character of his sport changes. More and more it
becomes an appeal to the wits, an appeal to wider experience and a
means of adding to it.
[Sidenote: A Child’s Play Fits it for the Future]
The higher amongst the lower animals also have their sports, which, in
every instance, are adapted to fit the members of the species for the
future business of life. Compare, for example, the ambush and pounce
of the kitten, the ardent chase and overthrow of the puppy, and the
climbing proclivities of the kid. As a general rule, in proportion as
an animal is capable of becoming intelligent, and as long as it is
so capable, it is inclined to sport. A cat loses the desire early in
life, a man retains it to the end. A child’s play, therefore, is no
indication of mere frivolity. It is the outward and visible sign of an
eager and splendidly directed mental activity. Curiosity also prompts
the child to store its memory. Imitativeness impels him to acquire
those mental traits which enabled his progenitors to survive in their
world. Parental love prompts to the care and instruction of offspring.
Very illuminating and beautiful is the instinctive delight of some dull
and careworn mother in babyish play with her infant, and her joy when
it first “takes notice,” and in its earliest beginnings of speech and
locomotion.