introduction or his transmutation into other forms of existence. He
leaves the mystery of creation where it was; but in connection with
the subsequent history of life we can learn from him a little as to
the laws which have governed the succession of animals in geological
time. First, we may learn that the plan of creation has been
progressive, that there has been an advance from the few, low, and
generalized types of the primeval ocean to the more numerous, higher,
and more specialized types of more recent times. Secondly, we learn
that the lower types, when first introduced, and before they were
subordinated to higher forms of life, existed in some of their grandest
modifications as to form and complexity, and occupied very important
places in the economy of the world, and that in succeeding ages, when
higher types were replacing them they were subjected to decay and
degeneracy. Thirdly, we learn that while the species has a limited term
of existence in geological time, any grand type of animal existence,
like that of the Foraminifera or of the Sponges, once introduced,
continues and finds throughout all the vicissitudes of the earth some
appropriate residence. Fourthly, as to the mode of introduction of new
types, or whether such creatures as Eozoon had any direct connection
with the subsequent introduction of mollusks, worms, or crustaceans, it
is altogether silent, nor can it predict anything as to the order or
manner of their introduction.
Had we been permitted to visit the Laurentian seas, and to study
Eozoon and its contemporary Protozoa when alive, it is plain that we
could not have foreseen or predicted from the consideration of such
organisms the future development of life. No amount of study of the
prototypal Foraminifer could have led us distinctly to the conception
of even a Sponge or a Polyp, much less of any of the higher animals.
Why is this? The answer is that the improvement into such higher types
does not take place by any change of the elementary sarcode, either in
those chemical, mechanical, or vital properties which we can study, but
in the adding to it of new structures. In the Sponge, which is perhaps
the nearest type of all, we have the movable pulsating cilium and true
animal cellular tissue, and along with this the spicular or fibrous
skeleton, these structures leading to an entire change in the mode of
life and subsistence. In the higher types of animals it is the same.
Even in the highest we have white blood-corpuscles and germinal matter,
which, in so far as we know, carry on no higher functions of life than
those of an Amœba; but they are now made subordinate to other kinds of
tissue, of great variety and complexity, which never have been observed
to arise out of the growth of any Protozoon. There would be only a
very few conceivable inferences which the highest finite intelligence
could deduce as to the development of future and higher animals. He
might infer that the foraminiferal sarcode, once introduced, might be
the substratum or foundation of other but unknown tissues in the higher
animals, and that the Protozoan type might continue to subsist side
by side with higher forms of living things as they were successively
introduced. He might also infer that the elevation of the animal
kingdom would take place with reference to those new properties of
sensation and voluntary motion in which the humblest animals diverge
from the life of the plant.
It is important that these points should be clearly before our minds,
because there has been current of late among naturalists a loose way
of writing with reference to them, which seems to have imposed on many
who are not naturalists. It has been said, for example, that such an
organism as Eozoon may include potentially all the structures and
functions of the higher animals, and that it is possible that we might
be able to infer or calculate all these with as much certainty as we
can calculate an eclipse or any other physical phenomenon. Now, there
is not only no foundation in fact for these assertions, but it is from
our present standpoint not conceivable that they can ever be realized.
The laws of inorganic matter give no data whence any _à priori_
deductions or calculations could be made as to the structure and
vital forces of the plant. The plant gives no data from which we can
calculate the functions of the animal. The Protozoon gives no data from
which we can calculate the specialties of the Mollusc, the Articulate,
or the Vertebrate. Nor unhappily do the present conditions of life of
themselves give us any sure grounds for predicting the new creations
that may be in store for our old planet. Those who think to build a
philosophy and even a religion on such data are mere dreamers, and have
no scientific basis for their dogmas. They are more blind guides than
our primeval Protozoon himself would be, in matters whose real solution
lies in the harmony of our own higher and immaterial nature with the
Being who is the author of all life--the Father "from whom every family
in heaven and earth is named."
_SOME GENERAL CONCLUSIONS_
XI
_SOME GENERAL CONCLUSIONS_
It may very properly be said that many elements of uncertainty
accompany the questions discussed in the previous chapters, and that
in any case our information is too scanty to warrant any positive
conclusions respecting the origin and earliest history of living
beings. On the other hand, it is well to take stock of what we do know,
and even of what we may reasonably suppose; keeping always in view
the fact that some parts of the problem of the origin of life are at
present insoluble, and may possibly ever continue in that condition. I
may, therefore, profitably close with a summary of what at present seem
to be ultimate facts and principles in this matter, which, if we have
not yet fully attained to, we may at least keep in view as objective
points.
If we admit that Eozoon was an animal, we may either assume that it
was the first introduced on the earth, or that there were earlier and
possibly even simpler creatures. In either case we begin the chain of
animal life with a Protozoan belonging to one of the simpler or more
generalized types of that group, and entitled to the name, both because
of its place in order of time and of rank in the development of the
animal kingdom. If we deny the claims of Eozoon, then the base of our
animal system must for the present be found in the Sponges, Worms,
Foraminifera, and Radiolarians of the Huronian, with the problematical
laminated forms allied to Cryptozoon which seem to occur even in the
Upper Laurentian. Thus in this case the miracle of creation stands
before us in a somewhat more complex form, though greatly less so than
if we had to accept the fauna of the Lower Cambrian as the oldest known.
Under any supposition we cannot hope to get beyond a Protozoan or a
few Protozoa, and we must assume that these could perform perfectly
in their simple way those functions of assimilation, organic
growth, reproduction, sensation, and spontaneous motion, which are
characteristic of these lowest forms of life in the present world.
It is plain, finally, that however simple we imagine this first
possessor of animal life to be, we can have no scientific evidence
of its origination either as an embryo or as an adult. If it had no
living ancestors, we are thus face to face with the problem of the
origin of animal life, either by what has been termed "Abiogenesis" of
a merely physical and fortuitous kind, or by creation. This implies
the previous production of the complex organic compound known as
"Protoplasm," which can, so far as we know, be produced only through
the agency of previously living "Protoplasm" formed by living plants.
We have, therefore, to presuppose the "Abiogenesis" or creation of
plants as predecessors of the animal; but here the same difficulty
meets us. We have next to imagine the spontaneous origin of the
structures of the "Protozoon"--its outer and inner substance, its
nucleus, its pulsating vesicle, and its pseudopods, with its protective
test, and its endowment with vital powers of locomotion, sensation,
assimilation, nutrition, and reproduction. Can we suppose that all this
could come of the chance interaction of physical causes?
At present the production of the living from the non-living seems to
be an impossibility, and the suggestion that at some vastly distant
point of past time physical conditions may have been so different
from those at present existing as to permit spontaneous generation
is of no scientific value. But if the existence of one primitive
Protozoon be granted, what reason have we to believe that it contains
potentially the germ of all the succeeding creatures in the great chain
of life, and the power of co-ordinating these with the successive
physical changes of the geological ages, and so producing the vast and
complicated system of the animal kingdom, extending up to the present
time? In doing so, we either elevate a low form of animal life into
the role of Creator, or fall back on indefinite chance, with infinite
probabilities against us. Reason, in short, requires us to believe in
a First Cause, self-existent, omnipotent and all-wise, designing from
the first a great and homogeneous plan, of which as yet but little
has been discovered by us. Thus any rational scheme of development of
the earth's population in geological time must be, not an agnostic
evolution, but a reverent inquiry into the mode by which it pleased the
Creator to proceed in His great work.
Regarding the matter in this way, there is legitimate scope for science
in tracing the long lines of the different types of ancient animals to
the modern period, and endeavouring to discover which of our so-called
species are original types and which are mere derivative varieties or
races.
It is evident that nothing is gained here by assuming that the whole
geological record is but one of innumerable vast æons of æons, which
have gone on in endless succession. If the world is made to stand
on an elephant, and this on a tortoise, and this on lower forms, it
helps us not at all if the last supporter must stand on nothing. The
difficulty thus postponed only becomes greater; and at the end we have
to imagine, not only life and organization, but even matter and energy
as fortuitously originating or creating themselves, unless produced by
an Almighty Eternal Will.
In pursuing studies of this kind, it is best for the present to content
ourselves with tracing the continuous chains of similar creatures
throughout their extension in geological time, rather than to seek for
connecting links between different lines of being. I endeavoured some
years ago to give a popular outline of this method in a little work
entitled "The Chain of Life in Geological Time."[49]
[Footnote 49: Religious Tract Society, London; Revell Publishing Co.,
New York, Chicago, and Toronto.]
Taking, for example, the earliest Protozoa--the Foraminifera and
Radiolaria--we find two lines of being that in endless varieties, but
with little material change, extend from the earliest periods to the
present time. In successive ages they are represented by families,
genera, and species, which are regarded as distinct, and known by
different names. But these humble animals are very variable, and what
seem to us to be new types may be merely varieties of ancestral forms.
We might even affirm that, for all we know, these two great groups,
as they exist in the present ocean, are lineal descendants of those
that flourished in the Eozoic. We could not prove this, unless we were
to find somewhere a continuous succession of deep-sea deposits that
would show the gradual changes that had occurred. On the other hand, it
is hard to believe that one individual life, so to speak, could have
continued unimpaired to animate successive and increasing masses of
matter in all the vast time extending from the Eozoic to the modern.
It is also at least equally possible that the causes and conditions,
whatever they were, that produced the earliest Protozoa may have acted
again and again in later times, originating new lines of descent with
renewed vitality.
Still, the tracing of these almost incredibly long lines of descent,
if they are such, is a proper, though difficult, subject of scientific
research, whatever may be the result. Something has been attempted in
this direction over limited portions of time; but a vast amount of
patient labour is required before certainty can be attained even in
this department of investigation.
When, on the other hand, we turn to the question whether such lines
of creation or descent have given off branches leading to new types,
as, for instance, from Protozoa to various Crustaceans or Mollusks,
we are entirely destitute of facts, and the statement lately made
by a leading agnostic evolutionist, that "if there is any truth in
the doctrine of evolution, every class of the animal kingdom must be
vastly older than the past records of its appearance on the surface of
the globe," shows us that all the attempts to construct genealogical
trees of the descent of animals are, so far as at present known, quite
visionary. It seems, indeed, that each leading line, as we trace it
back, ends in a blind alley, just where we might suppose that it was
about to pass into another path. This is one reason of the frequent
complaints as to the imperfection of the geological record, and of the
occurrence of "missing links" between different types of being. The
only feasible explanations of this are as yet the suppositions that
the times of introduction of new types may have been unfavourable to
the preservation of their remains, or that the first representatives
of each new group were soft-bodied animals incapable of preservation,
or that they happened to be introduced in regions yet unexplored. But
such accidents could scarcely have been the rule in every case. Even in
relation to man himself, he is still man in all the deposits in which
we can find his remains, and as remote from the apes of his time, in so
far as we know, as he is from those now his contemporaries. It would
seem, in short, as if, ashamed of his humble origin, he had carefully
obliterated his tracks in ascending from his lowly parentage to the
dignity of humanity. But in this he is only following the example of
other animals, his predecessors. We may, as is now constantly done
by evolutionists, fill up these gaps by plausible conjectures; but
this is not a scientific mode of procedure, unless we are content to
regard these conjectures as working hypotheses in aid of researches yet
without result.
It is important that general truths of this kind, impressed upon us by
our descent to the ascertained beginnings of life, should be generally
known, as counteractive to the confident statements so frequently put
forth by enthusiastic speculators and caterers of sensational popular
science. In point of fact, we still occupy the position so long ago
defined by the Apostle Paul, that "God's invisible things from the
creation of the world are clearly seen, being understood by the things
that are made, even His eternal power and divinity"; and the rational
student of nature must still be a pupil in the school of the Almighty
Maker of all things.
Realizing this, we can learn something both as to the dignity and the
humility of our own position. On the one hand we perceive that, in
the whole chain of life, man is the only being in the likeness of the
Maker, fitted to be His deputy in the world, to understand His great
work, and to be the heir of the whole. To man alone He has proclaimed,
"I have said ye are gods, and all of you children of the Most High." To
man alone has He given that "inspiration of the Almighty" which makes
Him the interpreter of nature. On the other hand, when we consider the
long extent in time of the great chain of life before man, and along
with this the vast oceanic area inaccessible to us, yet ever since the
dawn of life teeming with living things innumerable, we find that man
is not even in this little world the only object of Divine care, and we
learn a lesson of humility and of the obligations which rest on us not
only in relation to our fellow-men, but toward our humbler companions
who share with us the care of their Father and ours.
Finally, it is plain that scientific investigation can never bring us
within reach of the absolute origin of life, otherwise than by the
action of a creative Will. Had we stood on the earliest shore, and had
we seen living things appear in the waters where before had been merely
inorganic sand or rock, we should have known as little as we know
to-day of even the proximate causes of this new departure in nature.
If agnostics, we might have said, "this is spontaneous generation";
but such an expression would convey no distinct idea of the nature
of the change which had occurred. It would be merely a cloak for our
ignorance. If theists, we might say, "this is creation"; but we would
have heard no audible fiat, nor seen any process or manipulation, nor
known by what subordinate agency, if any, the result was produced. We
could have given no further explanation than that of the ancient writer
who tells us that God said, "Let the waters swarm with swarmers." We
are told that when these great creative changes occurred, they were
witnessed by higher intelligences than man. "Then the morning stars
sang together, and all the sons of God shouted for joy"[50]; but
even they could perhaps know little more than we, though they might
be better able to trace the future development of the wonderful plan
commenced in the humble Protozoa and culminating in man and immortality.
[Footnote 50: Job xxxviii. 7.]
_APPENDIX_
_APPENDIX_
* * * * *
A. Geological Relations of Eozoon, Archæozoon, etc.
IN the text I have given the arrangement of the pre-Cambrian
rock-formations of Canada, as understood by me at the time of the
delivery of the lectures on which this work is based--an arrangement
which I believe will, in the main, be sustained by the work of the
future, but which cannot as yet be received as final. The work of
Logan and Murray, so far as I have had opportunity to go over their
ground, was admirable; but since their time the progress in the
settlement of the country, the extension of railways, and other means
of communication, and the opening up of mineral deposits have greatly
increased the means of obtaining information, and detailed explorations
have been in progress under the Geological Survey of Canada. At this
moment, under the new Director of the Survey, Dr. G. M. Dawson, much
work is being done in this difficult field, more especially by Dr.
Ells, Dr. Adams, and Mr. Barlow, which it may be hoped will go far
to settle finally the arrangement and distribution of pre-Cambrian
rocks in the Northern part of the American Continent. The maps and
detailed reports representing these explorations are not yet before
the public, but from some preliminary notices which have appeared in
scientific periodicals, it may be inferred that the distinction between
the fundamental gneiss, with its associated igneous products, and the
Upper Laurentian, will become greater than was supposed by Logan. The
Lowest Laurentian or Trembling Mountain series of Logan now represents
a very widely extended basement formation, not so far as can be
ascertained, composed of sedimentary rocks in a metamorphosed state,
but rather of peculiar aqueo-igneous materials, different from the
greater part of those which succeeded them, and associated with varied
and extensive igneous intrusions and _in-meltings_ like those which
Keilhau ascertained long ago in the case of similar rocks in Norway.
The Grenville series, on the other hand, may prove to be a remnant of
an overlying system, originally less extensive or bordering the older
group, and greatly attenuated by the enormous denudation which the
whole region has undergone.
[Illustration: Fig. 60.--_Eozoon Canadense._
Portion of a large specimen. Nature-printed. Showing the laminæ, and
irregular cavities filled with serpentine, perhaps corresponding to the
funnels.]
[_To face p. 296._
It may also be found that the beds of limestone are fewer and their
repetitions more numerous than had been supposed, and that the
Grenville series may be closely associated locally, at least, with
beds hitherto of uncertain age, or associated with the Lower Huronian.
The Huronian proper, on the other hand, may be considerably extended,
and the Kewenian and Animiké series overlying it have already been
ascertained by the Canadian Geological Survey to overlap the Huronian
and Laurentian over vast areas between the great lakes and the Arctic
sea, evidencing much submergence at the close of the Huronian age, and
opening of the Palæozoic. I have noticed in the text the apparently
wide development of deposits of this age over the area of the Rocky
Mountains of Canada, and the corresponding territories in the United
States. There would seem to be in these regions a great thickness of
unaltered sediments between the Lower Cambrian and the crystalline
rocks below, representing the Huronian and Laurentian. In these very
few fossils have yet been found, but they afford perhaps the most
promising field, next to their representatives in Newfoundland and
New Brunswick, for the discovery of the predecessors of the Olenellus
fauna, and the forms of life connecting these with those known in the
Huronian and Laurentian. [For summaries of facts on the last-mentioned
subject, see Report of Dr. G. M. Dawson on the Kamloops map-sheet, in
"Reports of Geological Survey of Canada," vol. vii. B, new series,
pp. 29 _et seq._; also Reports of Dr. C. D. Walcott, U. S. Geological
Survey, vol. xiv., Part I., pp. 103 _et seq._, and Part II., pp. 503
_et seq._]
* * * * *
B. Preservation of Organic Remains by Injection with Hydrous Silicates.
The late Dr. T. Sterry Hunt contributed to the original paper on
Eozoon in the Journal of the Geological Society, a valuable essay on
the mineralization of fossils by serpentine, glauconite, and allied
hydrous silicates. This was in part reprinted in the notes appended
to one of the chapters of "The Dawn of Life," and the subject was
further discussed by Hunt in his invaluable work, "Chemical and
Geological Essays," and more especially in the chapter on the "Origin
of Crystalline Rocks," a chapter which every geologist deserving the
name should study with care.
I give here some of the more important facts referred to by Hunt, and
may add that subsequent microscopic studies have familiarized me with
the occurrence of serpentine and other hydrous silicates as fillings
of the cavities of fossils of various geological ages, insomuch that I
have come to regard the occurrence of these rocks in association with
fossiliferous limestones as among the best available means to enable us
to ascertain the minute structures of shells, Foraminifera, corals, etc.
The following remarks and analyses further illustrate Hunt's views on
the relations of these minerals, with some of the facts on which they
are based:--
"In connection with the Eozoon it is interesting to examine more
carefully into the nature of the matters which have been called
glauconite or green-sand. These names have been given to substances of
unlike composition, which, however, occur under similar conditions,
and appear to be chemical deposits from water, filling cavities in
minute fossils, or forming grains in sedimentary rocks of various ages.
Although greenish in colour, and soft and earthy in texture, it will
be seen that the various glauconites differ widely in composition.
The variety best known, and commonly regarded as the type of the
glauconites, is that found in the green-sand of Cretaceous age in
New Jersey, and in the Tertiary of Alabama; the glauconite from the
Lower Silurian rocks of the Upper Mississippi is identical with it
in composition. Analysis shows these glauconites to be essentially
hydrous silicates of protoxyd of iron, with more or less alumina, and
small but variable quantities of magnesia, besides a notable amount of
potash. This alkali is, however, sometimes wanting, as appears from
the analysis of a green-sand from Kent, in England, by that careful
chemist, the late Dr. Edward Turner, and in another examined by
Berthier, from the calcaire grassier, near Paris, which is essentially
a serpentine in composition, being a hydrous silicate of magnesia and
protoxyd of iron. A comparison of these last two will show that the
loganite, which fills the ancient Foraminifer of Burgess, is a silicate
nearly related in composition.