the present condition of things has endured for a comparatively short
time; and, at the commencement of that time, came into existence within
the course of six days. I doubt not that it may have excited some surprise
in your minds that I should have spoken of this as Milton's hypothesis,
rather than that I should have chosen the terms which are more customary,
such as "the doctrine of creation," or "the Biblical doctrine," or "the
doctrine of Moses," all of which denominations, as applied to the
hypothesis to which I have just referred, are certainly much more familiar
to you than the title of the Miltonic hypothesis. But I have had what I
cannot but think are very weighty reasons for taking the course which I
have pursued. In the first place, I have discarded the title of the
"doctrine of creation," because my present business is not with the
question why the objects which constitute nature came into existence, but
when they came into existence, and in what order. This is as strictly a
historical question as the question when the Angles and the Jutes invaded
England, and whether they preceded or followed the Romans. But the
question about creation is a philosophical problem, and one which cannot
be solved, or even approached, by the historical method. What we want to
learn is, whether the facts, so far as they are known, afford evidence
that things arose in the way described by Milton, or whether they do not;
and, when that question is settled, it will be time enough to inquire into
the causes of their origination.
In the second place, I have not spoken of this doctrine as the Biblical
doctrine. It is quite true that persons as diverse in their general views
as Milton the Protestant and the celebrated Jesuit Father Suarez, each put
upon the first chapter of Genesis the interpretation embodied in Milton's
poem. It is quite true that this interpretation is that which has been
instilled into every one of us in our childhood; but I do not for one
moment venture to say that it can properly be called the Biblical
doctrine. It is not my business, and does not lie within my competency, to
say what the Hebrew text does, and what it does not signify; moreover,
were I to affirm that this is the Biblical doctrine, I should be met by
the authority of many eminent scholars, to say nothing of men of science,
who, at various times, have absolutely denied that any such doctrine is to
be found in Genesis. If we are to listen to many expositors of no mean
authority, we must believe that what seems so clearly defined in
Genesis--as if very great pains had been taken that there should be no
possibility of mistake--is not the meaning of the text at all. The account
is divided into periods, which we may make just as long or as short as
convenience requires. We are also to understand that it is consistent with
the original text to believe that the most complex plants and animals may
have been evolved by natural processes, lasting for millions of years, out
of structureless rudiments. A person who is not a Hebrew scholar can only
stand aside and admire the marvelous flexibility of a language which
admits of such diverse interpretations. But assuredly, in the face of such
contradictions of authority upon matters respecting which he is
incompetent to form any judgment, he will abstain, as I do, from giving
any opinion.
In the third place, I have carefully abstained from speaking of this as
the Mosaic doctrine, because we are now assured upon the authority of the
highest critics, and even of dignitaries of the Church, that there is no
evidence that Moses wrote the Book of Genesis, or knew anything about it.
You will understand that I give no judgment--it would be an impertinence
upon my part to volunteer even a suggestion--upon such a subject. But,
that being the state of opinion among the scholars and the clergy, it is
well for the unlearned in Hebrew lore, and for the laity, to avoid
entangling themselves in such a vexed question. Happily, Milton leaves us
no excuse for doubting what he means, and I shall therefore be safe in
speaking of the opinion in question as the Miltonic hypothesis.
Now we have to test that hypothesis. For my part, I have no prejudice one
way or the other. If there is evidence in favor of this view, I am
burdened by no theoretical difficulties in the way of accepting it; but
there must be evidence. Scientific men get an awkward habit--no, I won't
call it that, for it is a valuable habit--of believing nothing unless
there is evidence for it; and they have a way of looking upon belief which
is not based upon evidence, not only as illogical, but as immoral. We
will, if you please, test this view by the circumstantial evidence alone;
for, from what I have said, you will understand that I do not propose to
discuss the question of what testimonial evidence is to be adduced in
favor of it. If those whose business it is to judge are not at one as to
the authenticity of the only evidence of that kind which is offered, nor
as to the facts to which it bears witness, the discussion of such evidence
is superfluous. But I may be permitted to regret this necessity of
rejecting the testimonial evidence the less, because the examination of
the circumstantial evidence leads to the conclusion, not only that it is
incompetent to justify the hypothesis, but that, so far as it goes, it is
contrary to the hypothesis.
The considerations upon which I base this conclusion are of the simplest
possible character. The Miltonic hypothesis contains assertions of a very
definite character relating to the succession of living forms. It is
stated that plants, for example, made their appearance upon the third day,
and not before. And you will understand that what the poet means by plants
are such plants as now live, the ancestors, in the ordinary way of
propagation of like by like, of the trees and shrubs which flourish in the
present world. It must needs be so: for, if they were different, either
the existing plants have been the result of a separate origination since
that described by Milton, of which we have no record, or any ground for
supposition that such an occurrence has taken place; or else they have
arisen by a process of evolution from the original stocks.
In the second place, it is clear that there was no animal life before the
fifth day, and that, on the fifth day, aquatic animals and birds appeared.
And it is further clear that terrestrial living things, other than birds,
made their appearance upon the sixth day, and not before. Hence, it
follows that if, in the large mass of circumstantial evidence as to what
really has happened in the past history of the globe we find indications
of the existence of terrestrial animals, other than birds, at a certain
period, it is perfectly certain that all that has taken place since that
time must be referred to the sixth day.
In the great Carboniferous formation, whence America derives so vast a
proportion of her actual and potential wealth, in the beds of coal which
have been formed from the vegetation of that period, we find abundant
evidence of the existence of terrestrial animals. They have been
described, not only by European but by American naturalists. There are to
be found numerous insects allied to our cockroaches. There are to be found
spiders and scorpions of large size, the latter so similar to existing
scorpions that it requires the practised eye of the naturalist to
distinguish them. Inasmuch as these animals can be proved to have been
alive in the Carboniferous epoch, it is perfectly clear that, if the
Miltonic account is to be accepted, the huge mass of rocks extending from
the middle of the Palaeozoic formations to the uppermost members of the
series must belong to the day which is termed by Milton the sixth.
But, further, it is expressly stated that aquatic animals took their
origin upon the fifth day, and not before; hence, all formations in which
remains of aquatic animals can be proved to exist, and which therefore
testify that such animals lived at the time when these formations were in
course of deposition, must have been deposited during or since the period
which Milton speaks of as the fifth day. But there is absolutely no
fossiliferous formation in which the remains of aquatic animals are
absent. The oldest fossils in the Silurian rocks are exuviae of marine
animals; and if the view which is entertained by Principal Dawson and Dr.
Carpenter respecting the nature of the Eozoon be well founded, aquatic
animals existed at a period as far antecedent to the deposition of the
coal as the coal is from us; inasmuch as the Eozoon is met with in those
Laurentian strata which lie at the bottom of the series of stratified
rocks. Hence it follows, plainly enough, that the whole series of
stratified rocks, if they are to be brought into harmony with Milton, must
be referred to the fifth and sixth days, and that we cannot hope to find
the slightest trace of the products of the earlier days in the geological
record. When we consider these simple facts, we see how absolutely futile
are the attempts that have been made to draw a parallel between the story
told by so much of the crust of the earth as is known to us and the story
that Milton tells. The whole series of fossiliferous stratified rocks
must be referred to the last two days; and neither the Carboniferous nor
any other formation can afford evidence of the work of the third day.
Not only is there this objection to any attempt to establish a harmony
between the Miltonic account and the facts recorded in the fossiliferous
rocks, but there is a further difficulty. According to the Miltonic
account, the order in which animals should have made their appearance in
the stratified rocks would be this: fishes, including the great whales,
and birds; after them, all varieties of terrestrial animals except birds.
Nothing could be further from the facts as we find them; we know of not
the slightest evidence of the existence of birds before the Jurassic, or
perhaps the Triassic, formation; while terrestrial animals, as we have
just seen, occur in the Carboniferous rocks. If there were any harmony
between the Miltonic account and the circumstantial evidence, we ought to
have abundant evidence of the existence of birds in the Carboniferous, the
Devonian, and the Silurian rocks. I need hardly say that this is not the
case, and that not a trace of birds makes its appearance until the far
later period which I have mentioned.
And again, if it be true that all varieties of fishes and the great
whales, and the like, made their appearance on the fifth day, we ought to
find the remains of these animals in the older rocks--in those which were
deposited before the Carboniferous epoch. Fishes we do find, in
considerable number and variety; but the great whales are absent, and the
fishes are not such as now live. Not one solitary species of fish now in
existence is to be found in the Devonian or Silurian formations. Hence we
are introduced afresh to the dilemma which I have already placed before
you: either the animals which came into existence on the fifth day were
not such as those which are found at present, are not the direct and
immediate ancestors of those which now exist,--in which case either fresh
creations of which nothing is said, or a process of evolution, must have
occurred,--or else the whole story must be given up, as not only devoid of
any circumstantial evidence, but as contrary to such evidence as exists.
I placed before you in a few words, some little time ago, a statement of
the sum and substance of Milton's hypothesis. Let me now try to state, as
briefly, the effect of the circumstantial evidence bearing upon the past
history of the earth which is furnished, without the possibility of
mistake, with no chance of error as to its chief features, by the
stratified rocks. What we find is that the great series of formations
represents a period of time of which our human chronologies hardly afford
us a unit of measure. I will not pretend to say how we ought to estimate
this time, in millions or in billions of years. For my purpose, the
determination of its absolute duration is wholly unessential; but
unquestionably the time was enormous.
It results from the simplest methods of interpretation, that, leaving out
of view certain patches of metamorphosed rocks, and certain volcanic
products, all that is now dry land has once been at the bottom of the
waters. It is perfectly certain that, at a comparatively recent period of
the world's history,--the Cretaceous epoch,--none of the great physical
features, which at present mark the surface of the globe, existed. It is
certain that the Rocky Mountains were not. It is certain that the Himalaya
Mountains were not. It is certain that the Alps and the Pyrenees had no
existence. The evidence is of the plainest possible character, and is
simply this: we find raised up on the flanks of these mountains, elevated
by the forces of upheaval which have given rise to them, masses of
Cretaceous rock which formed the bottom of the sea before those mountains
existed. It is therefore clear that the elevatory forces which gave rise
to the mountains operated subsequently to the Cretaceous epoch; and that
the mountains themselves are largely made up of the materials deposited in
the sea which once occupied their place. As we go back in time, we meet
with constant alternations of sea and land, of estuary and open ocean;
and, in correspondence with these alternations, we observe the changes in
the fauna and flora to which I have referred.
But the inspection of these changes gives us no right to believe that
there has been any discontinuity in natural processes. There is no trace
of general cataclysms, of universal deluges, or of sudden destructions of
a whole fauna or flora. The appearances which were formerly interpreted in
that way have all been shown to be delusive, as our knowledge has
increased, and as the blanks which formerly appeared to exist between the
different formations have been filled up. That there is no absolute break
between formation and formation, that there has been no sudden
disappearance of all the forms of life and replacement of them by others,
but that changes have gone on slowly and gradually, that one type has died
out and another has taken its place, and that thus, by insensible degrees,
one fauna has been replaced by another, are conclusions strengthened by
constantly increasing evidence. So that within the whole of the immense
period indicated by the fossiliferous stratified rocks there is assuredly
not the slightest proof of any break in the uniformity of nature's
operations, no indication that events have followed other than a clear and
orderly sequence.
That, I say, is the natural and obvious teaching of the circumstantial
evidence contained in the stratified rocks. I leave you to consider how
far, by any ingenuity of interpretation, by any stretching of the meaning
of language, it can be brought into harmony with the Miltonic hypothesis.
ON THE PHYSICAL BASIS OF LIFE
In order to make the title of this discourse generally intelligible, I
have translated the term "protoplasm," which is the scientific name of the
substance of which I am about to speak, by the words "the physical basis
of life." I suppose that, to many, the idea that there is such a thing as
a physical basis, or matter, of life may be novel, so widely spread is the
conception of life as a something which works through matter, but is
independent of it; and even those who are aware that matter and life are
inseparably connected may not be prepared for the conclusion--plainly
suggested by the phrase, "_the_ physical basis or matter of life,"--that
there is some one kind of matter which is common to all living beings, and
that their endless diversities are bound together by a physical, as well
as an ideal, unity. In fact, when first apprehended, such a doctrine as
this appears almost shocking to common sense.
What, truly, can seem to be more obviously different from one another, in
faculty, in form, and in substance, than the various kinds of living
beings? What community of faculty can there be between the brightly
colored lichen, which so nearly resembles a mere mineral incrustation of
the bare rock on which it grows, and the painter, to whom it is instinct
with beauty, or the botanist, whom it feeds with knowledge?
Again, think of the microscopic fungus--a mere infinitesimal ovoid
particle, which finds space and duration enough to multiply into countless
millions in the body of a living fly; and then of the wealth of foliage,
the luxuriance of flower and fruit, which lies between this bald sketch
of a plant and the giant pine of California, towering to the dimensions of
a cathedral spire, or the Indian fig, which covers acres with its profound
shadow, and endures while nations and empires come and go around its vast
circumference. Or, turning to the other half of the world of life, picture
to yourselves the great Finner whale, hugest of beasts that live or have
lived, disporting his eighty or ninety feet of bone, muscle, and blubber,
with easy roll, among waves in which the stoutest ship that ever left
dockyard would founder hopelessly; and contrast him with the invisible
animalcules--mere gelatinous specks, multitudes of which could, in fact,
dance upon the point of a needle with the same ease as the angels of the
Schoolmen could, in imagination. With these images before your minds, you
may well ask, what community of form, or structure, is there between the
animalcule and the whale, or between the fungus and the fig tree? And, _a
fortiori_, between all four?
Finally, if we regard substance, or material composition, what hidden bond
can connect the flower that a girl wears in her hair and the blood that
courses through her youthful veins; or, what is there in common between
the dense and resisting mass of the oak, or the strong fabric of the
tortoise, and those broad disks of glassy jelly which may be seen
pulsating through the waters of a calm sea, but which drain away to mere
films in the hand which raises them out of their element?
Such objections as these must, I think, arise in the mind of everyone who
ponders, for the first time, upon the conception of a single physical
basis of life underlying all the diversities of vital existence; but I
propose to demonstrate to you that, notwithstanding these apparent
difficulties, a threefold unity--namely, a unity of power or faculty, a
unity of form, and a unity of substantial composition--does pervade the
whole living world.
No very abstruse argumentation is needed, in the first place, to prove
that the powers, or faculties, of all kinds of living matter, diverse as
they may be in degree, are substantially similar in kind.
Goethe has condensed a survey of all the powers of mankind into the
well-known epigram:--
Warum treibt sich das Volk so und schreit? Es will sich ernaehren,
Kinder zeugen, und die naehren so gut es vermag.
* * * * *
Weiter bringt es kein Mensch, stell' er sich wie er auch will.
In physiological language this means that all the multifarious and
complicated activities of man are comprehensible under three categories.
Either they are immediately directed toward the maintenance and
development of the body, or they effect transitory changes in the relative
positions of parts of the body, or they tend toward the continuance of the
species. Even those manifestations of intellect, of feeling, and of will,
which we rightly name the higher faculties, are not excluded from this
classification, inasmuch as, to everyone but the subject of them, they are
known only as transitory changes in the relative positions of parts of the
body. Speech, gesture, and every other form of human action are, in the
long run, resolvable into muscular contraction, and muscular contraction
is but a transitory change in the relative positions of the parts of a
muscle. But the scheme which is large enough to embrace the activities of
the highest form of life covers all those of the lower creatures. The
lowest plant, or animalcule, feeds, grows, and reproduces its kind. In
addition, all animals manifest those transitory changes of form which we
class under irritability and contractility; and it is more than probable
that, when the vegetable world is thoroughly explored, we shall find all
plants in possession of the same powers, at one time or other of their
existence.
I am not now alluding to such phenomena, at once rare and conspicuous, as
those exhibited by the leaflets of the sensitive plant, or the stamens of
the barberry, but to such more widely spread, and, at the same time, more
subtle and hidden, manifestations of vegetable contractility. You are
doubtless aware that the common nettle owes its stinging property to the
innumerable stiff and needle-like, though exquisitely delicate, hairs that
cover its surface. Each stinging needle tapers from a broad base to a
slender summit, which, though rounded at the end, is of such microscopic
fineness that it readily penetrates, and breaks off in, the skin. The
whole hair consists of a very delicate outer case of wood, closely applied
to the inner surface of which is a layer of semifluid matter, full of
innumerable granules of extreme minuteness. This semifluid lining is
protoplasm, which thus constitutes a kind of bag, full of a limpid liquid,
and roughly corresponding in form with the interior of the hair which it
fills. When viewed with a sufficiently high magnifying power, the
protoplasmic layer of the nettle hair is seen to be in a condition of
unceasing activity. Local contractions of the whole thickness of its
substance pass slowly and gradually from point to point, and give rise to
the appearance of progressive waves, just as the bending of successive
stalks of corn by a breeze produces the apparent billows of a cornfield.
But, in addition to these movements, and independently of them, the
granules are driven, in relatively rapid streams, through channels in the
protoplasm which seem to have a considerable amount of persistence. Most
commonly, the currents in adjacent parts of the protoplasm take similar
directions; and, thus, there is a general stream up one side of the hair
and down the other. But this does not prevent the existence of partial
currents which take different routes; and, sometimes, trains of granules
may be seen coursing swiftly in opposite directions, within a
twenty-thousandth of an inch of one another; while, occasionally, opposite
streams come into direct collision, and, after a longer or shorter
struggle, one predominates. The cause of these currents seems to lie in
contractions of the protoplasm which bounds the channels in which they
flow, but contractions so minute that the best microscopes show only their
effects, and not themselves.
The spectacle afforded by the wonderful energies prisoned within the
compass of the microscopic hair of a plant, which we commonly regard as a
merely passive organism, is not easily forgotten by one who has watched
its display, continued hour after hour, without pause or sign of
weakening. The possible complexity of many other organic forms, seemingly
as simple as the protoplasm of the nettle, dawns upon one; and the
comparison of such a protoplasm to a body with an internal circulation,
which has been put forward by an eminent physiologist, loses much of its
startling character. Currents similar to those of the hairs of the nettle
have been observed in a great multitude of very different plants, and
weighty authorities have suggested that they probably occur, in more or
less perfection, in all young vegetable cells. If such be the case, the
wonderful noonday silence of a tropical forest is, after all, due only to
the dullness of our hearing; and could our ears catch the murmur of these
tiny maelstroms, as they whirl in the innumerable myriads of living cells
which constitute each tree, we should be stunned, as with the roar of a
great city.