Part 15

Thus our dawn-animal has positively no story to tell as to his own 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

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."

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"; 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.

APPENDIX

APPENDIX

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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.

Portion of a large specimen. Nature-printed. Showing the laminæ, and irregular cavities filled with serpentine, perhaps corresponding to the funnels.]

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.]

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B. Preservation of Organic Remains by Injection with Hydrous Silicates.