Life: Its True Genesis Part 7

For the sake of the argument, however, we will suppose the northern ice-cap to have been even more imperative in its demands than Mr. Croll has deemed possible, driving some of our warm and cold temperate forms down into the lowlands of Columbia, Venezuela, etc., in the extreme northern portions of South America. But how would these forms have managed, even then, to cross the thermal equator and secure a permanent habitat in the present warm and cold temperate zones of that continent?

Manifestly, this question has never been practically solved, nor is it ever likely to be in our day or generation. It is nevertheless susceptible of solution, as Mr. Darwin thinks, by easy mental processes. We have only to take a bird's eye view of the situation, and mentally follow these forms in their long geographical tramp from the northern to the southern hemisphere.

They must have started, of course, some twenty thousand years or more before the earth reached its last superior limit of eccentricity. At that distant epoch the sub-arctic breezes must have been blowing pretty stiffly in our present temperate lat.i.tudes, and these forms would have been constrained, in due time, to seek a more congenial isotherm. They must accordingly have set out on their expedition, at about the period indicated, with the prospect of a long and tedious journey before them.

Some twenty thousand years must have transpired before they reached the line of the present Gulf states, and it would have taken as many more years for them to deploy to the right and successfully enter the Mexican states. In another twenty thousand years or so they might have doubled Vera Cruz, and headed, in a southeasterly direction, for the Central American states. The thermal equator would by this time have reached a point some thirty degrees south of the geographical equator, while the northern ice-cap would have swept down upon the traditional "hub of the universe," or some ten or twelve degrees in excess of Mr. Croll's calculations.

To have accomplished this grand glaciatorial feat the North Pole must have donned some twenty times the amount of ice now about both poles of the earth, and so changed the earth's centre of gravity as to have inundated every foot of land on its habitable surface. But if this terrible catastrophy had been avoided, and some of our extreme northern forms had forced their way through the Isthmus into the lowlands of Columbia, they must have done so at their greatest possible peril, even if they had reached the base of Old Mt. Tolima in advance of the thermal equator, now fleeing in dismay before the southern Ice-monarch, with all his isochimenal hosts in mad pursuit of their invaders. And if these adventurous northern forms had succeeded in ascending Mt. Tolima, they could never have got down again, with the a.s.sistance of forty glaciations.

But we can imagine Mr. Darwin promptly s.n.a.t.c.hing his pen to show the stupidity of these northern forms in not climbing Popocatepetl or some other lofty mountain in Central America or Mexico, on their retreat before the still advancing thermal equator. But how this would have helped them to cross the geographical equator, we fail to see. When Mr. Darwin, and the eminent corps of geologists and physicists accepting his solution of this "vexed question," can make a "warm term" south _succeed_ a "cold term" north, we shall have no difficulty in solving the problem ourself.

But, unfortunately, the two terms--the cold one north and the warm one south--are simultaneous in occurrence, and the same causes which forced these northern invaders into the tropics, when they followed _after_ the thermal equator, would have driven them ignominously back again _before_ it. The climbing of mountains would only have prolonged their disaster.

For after the glaciation north comes the glaciation south, and unless our cold temperate zone were pushed down beyond the geographical equator, none of its living forms could ever have reached the corresponding zone in the southern hemisphere.

But as this "migration theory" is one of paramount importance to modern science, and especially to "Darwinism," [19] distinctively so called, let us, at the risk of repet.i.tion and tediousness, propose a scientific expedition for the better solution of this problem. To do this, we propose to cut loose from our stupid predecessors, the plants and animals, and invite Mr. Darwin and some of his more distinguished European contemporaries, not omitting Professors Gray, Winch.e.l.l, Yeomans, and some few other American admirers of his, to accompany us on a fresh expedition from the warm and cold temperate zones north to the corresponding zones south, _purely in the interest of science_. To make it certain that the time fixed upon for this "expedition" to start, will not escape their attention, we will state what many of them already well know, that the present eccentricity of the earth's...o...b..t is very low, being only 0.0168, and that, in the year of our Lord 851,800, it will reach its next superior limit, with a few intervening oscillations of such minimum value as to render it hardly worth our while to start before that time.

We shall be obliged, of course to invite our distinguished European party to join us on this side of the Atlantic, as their own narrow and contracted continent furnishes no proper field for determining the problem in question. We shall insist upon one condition only: "_That they shall never leave the warm temperate zone in which we shall set out on our expedition, except to pa.s.s halfway into an adjoining zone as is the habit, at times, with plants and animals_." This condition will have to be rigidly observed, otherwise our expedition would be of no scientific value to future generations. As we shall have plenty of time to provide the necessary outfit, we will appoint Mr. Darwin purveyor-general of the party, and hold him responsible for any misadventure.

We will arrange for the expedition to start in the early autumn of the year of our Lord 831,800, or about twenty thousand years before the earth shall reach its next superior limit of eccentricity,--all of us eager, of course, to brave the climatic vicissitudes of the journey, and to solve the "great problem of the ages," which is, to determine how the gigantic elephantoids of the Eocene period managed to cross the thermal equator, and pa.s.s into the present arctic regions of our globe.

As "the king never dies," so the old southern Ice-monarch will be succeeded by the young northern one, at about the period named. We shall then have a decided advantage over our predecessors, the plants and animals, in their journey southward, since we shall know the exact route they took, and need only follow it. Presumably they had no such information, nor had they either chart or compa.s.s to guide them,--a circ.u.mstance which Mr. Darwin has not sufficiently taken into account in predicating intelligence of his favorite pedestrians. Besides, these vegetal and animal forms had one difficulty to encounter which we shall not experience. With all the northern forms driven down into the Central American states, they must have been sadly crowded for room, especially near the Isthmus. The social conifers must have monopolized all the more favored sites on the mountain sides and tops, while the humbler denizens of the forest must have contented themselves with still more limited quarters. The more impatient animals, for lack of necessary forage, must have crowded through the Isthmus only to be driven back by the tropical heats to their proper isotherms.

But our warm temperate zone is now moving southward, and our scientific expedition is moving with it. The northern Ice-monarch has resumed absolute sway, and our aphelion distance from the sun has increased some tens millions of miles. We have, in the mean time, moved down to the line of the Gulf states, and are deploying to the right in order to make a triumphant entry into Mexico. Mr. Darwin is daily consulting the isochimenals, and is confident that our northern ice-cap will equal Mr.

Croll's highest expectations. The news finally reaches us that the Gulf stream has turned its course southward, and is now pouring its immense treasures of heat into the South Atlantic, if not turning the African "horn" and was.h.i.+ng the far-off Australian coast. This fact greatly increases the enthusiasm of our European party, and they hasten forward into the sub-tropical zone, almost "violating conditions" in their haste to enter the tropics.

At length, we crowd the narrow pa.s.sages of the Isthmus, and the glory of a warm temperate climate bursts upon our view in the Columbian states, of South America. _The expedition promises to be an entire success_. At least, Mr. Darwin thinks so, and he is now the Sir Oracle of our party. We deliberately enter the lowlands of Columbia, and make ready to ascend the sub-tropical mountains--those formerly equatorial--where the "great scientific problem of the ages" is to be demonstrated. But we are measuring time by almost _Sirius_ distances, and vast geologic periods sweep by without apparent record. The northern ice-cap has been a prodigious one, crowding us nearly down to the geographical equator, with the advantage we have of appropriating some five and half degrees of the sub-tropical zone.

But the year Anno Domini 851,800 finally rolls round, and the maximum of the earth's ice-cap is reached. Old Mt. Tolima looms up in the distance, and we soon ascertain that its height is sufficient for all scientific purposes. Its summit displays a glittering ice-cap, and we are certain to find the proper isotherm by climbing its umbrageous sides. We accordingly make haste to reach its base, and get there not a minute too soon; for the young southern Ice-monarch has stolen a march on the thermal equator, and is driving it irresistibly back to its old quarters. His march northward is a continuous triumph and ovation up to 55A deg., and the heart of Patagonia is made glad by his near approach. True, the white gates of commerce are closed about the Horn; but that is no concern of these wild Patagonians.

The aggressive Britton is driven out of New Zealand, and that is another source of joy to the savage breast. Tasmania would extend a gladder welcome than all to the Ice-crowned monarch, but alas, not a drop of Tasmanian blood runs in human veins! Cape Good Hope has now a sub-arctic climate, and the heart of the wild Kaffir and Zulu rejoices that the sceptre of "perfidious Albion" is broken.

The thermal equator at length reaches the base of Mt. Tolima, and hastens northward to the Isthmus, and thence to Hondurus and New Guatemala, where, by sheer force of exhaustion, it comes to a halt.

But, as the equatorial zone extends fifteen degrees both ways from the thermal equator, its southern limit now rests on the geographical equator, and accordingly encircles the base of our "mount of refuge." We are now up this mountain some sixteen thousand feet above the equatorial lowlands, with the sub-tropical, tropical, and equatorial zones between us and the possibility of our further migration southward, without violating the express conditions imposed at the outset of our expedition.

The fact soon stares us in the face that we have been no more successful, in our efforts to cross the thermal equator and pa.s.s into high southern lat.i.tudes, than the stupid plants and animals before us; and Mr Darwin's faith in high mountains springing from equatorial lowlands, disappears in jest and derision as we all good-humoredly agree "to break conditions,"

and find our way back to the centres of activity and trade in the Old and New Worlds, leaving the great scientific problem of the ages to solve itself as best it may. We accordingly descend from our mountain fastness, hasten to the coast, and take pa.s.sage by steamer to Manhattan, the great commercial metropolis of the world. Here we find that the barometer of exchange was long ago taken down in London and hung up in New York. The Old Antiquarian Society rooms are the first object of interest sought by us. On making our way thither we look for a copy of the _Herald_, of the date of our departure, in which we find an account of the scientific expedition fitted out by us, facetiously termed "_The Great Wild-Goose Chase after the Thermal Equator_"--presenting one of the most humorous bits of sensational pleasantry ever given to the American public.

But an apology is due the staider reader for the seeming levity of this narrative adventure. The exposition of Mr. Darwin, though widely accepted on both sides of the Atlantic by the scientific world, has seemed to us too trivial for serious reply. If we have leaped over vast periods of time, it makes no difference with the argument. So long as the thermal equator, or more properly the equatorial zone, or any part of it, lies between the warm or cold temperate forms, whether plants or animals, and their point of destination in the southern hemisphere, they can never migrate thither, any more than the right whale of the arctic seas can swim the equatorial oceans. Nothing is gained by going out of the way to climb mountains, except to hopelessly r.e.t.a.r.d the return of both plants and animals to their native zones. If we have not demonstrated this fact to the reader's fullest comprehension, it will be useless for him ever to write a Q.E.D. at the end of any proposition.

It is true that some eminent astronomers and physicists hesitate to accept the theory that these glacial epochs are due to the eccentricity of the earth's...o...b..t. But the argument favoring it is well fortified and ably advanced, and if we add to the astronomical considerations involved, the physical proofs of a change in the earth's centre of gravity, caused by the excessive acc.u.mulation of ice about either pole, and the probable s.h.i.+fting of the Gulf stream to a southerly direction during the glacial period north, it is difficult to resist the conviction that the real cause of glaciation has been suggested in this theory. With all the ice now acc.u.mulated about the south pole transferred to the north pole, it would make an ice-cap of over thirty miles in thickness at the pole, and one sloping in all directions southward to about 60A deg.. This acc.u.mulation, it is claimed, would so change the earth's centre of gravity as to cause all the equatorial warm waters to flow southward instead of northward, as they now do.

This would certainly seem to be a most wonderful provision of nature, as well as one strongly calculated to impress the human mind with the belief that an Infinite _Pre_vision lies behind all possible _pro_vision, whether witnessed in the heavens or in the earth, in astronomical or physical phenomena. Everywhere we see infinite perfection, combined with infinite beneficence, in the adaptation of means to ends. Nothing runs to waste--all things are conserved for use.

But in all the outspoken grandeur of the universe, there is nothing so grand, in exhibition at least, as the simple faith of a child, that "He who watereth the hills from his chambers," and "causeth the day-spring to know his place," will watch over the trustful little sleeper during the darkness and silence of the night.

Chapter VI.

The Distribution and Premanence of Species.

Professor Gray, in his address before the American a.s.sociation for the advancement of science, delivered at Dubuque (Ia.) in 1872, while remarking upon the wide extent of similar flora in the same plant zones, says: "If we now compare, as to their flora generally, the Atlantic United States with j.a.pan, Mantchooria and Northern China,--_i.e._ Eastern North America with Eastern North Asia--half the earth's circ.u.mference apart, we find an astonis.h.i.+ng similarity." But why astonis.h.i.+ng? Had our distinguished botanical professors, in this country and in Europe, thoroughly informed themselves as to the climatic conditions, the general physical features, geographical characteristics, soil-const.i.tuents, and other conditional incidences of this Asiatic region, in the light of all the physiological facts before them, the circ.u.mstance of this great similarity of flora would have been anything but astonis.h.i.+ng. Indeed, the astonishment, if any, would have been expressed at the want of similarity, had it been found to exist.

Ever since 1862, these distinguished professors have had the great plant-charts of Mr. Arthur Renfrey before them, with the warm temperate zone north accurately laid down in its proper isotherms, as well as the different cla.s.ses of vegetation peculiar to the two regions referred to, and some general conclusions of value to science might have been drawn therefrom. Besides, the fact of these similar antipodal flora was well known to many of them before this chart was issued. They also knew that all along the higher mountain ranges of this country, as well as in Europe, the same alpine flora was to be found under the same or similar alpine conditions. From Mt. St. Elias, in Alaska, to the Central American States, and thence, through the Isthmus, to the southern extremity of the Andes in South Patagonia, there is one unbroken line of alpine vegetation pressing the sides or summits of the loftier mountain ranges, at alt.i.tudes correspondingly varying with the lat.i.tudes in which they occur. And the same is true of the Alps in Europe and the Himalaya ranges in Asia, if not of all the mountain systems of the globe.

These, and hundreds of other equally suggestive facts, all pointing to geographical, climatic, and other influencing conditions, as the real objective points of inquiry, have been constantly before our botanical friends; and yet they have been content with Mr. Darwin's theory of climbing mountains to cross the geographical equator, under the impression that an enormous ice-cap, or rather prodigious "ice-ulster," would ultimately drift them into the southern hemisphere, or enable them to "coast" their way thither with the greatest imaginable ease. But why insist upon the migration of plants growing in the lowlands and about the bases and sides of mountains, and not suggest some means of transport for the equally beautiful flora, known as "alpine," on the mountain summits of the earth? These are distributed, as we have before shown, over all our mountain systems, in all lat.i.tudes and in all parts of the globe, as well as in the higher regions of vegetation as we approach the north pole.

Surely, the delicate little harebells of these alpine regions should attract some interest, if not sympathy, from those who are constantly hunting up means of transport for the more hardy and robust plants that seem able to take care of themselves almost anywhere.

When the next great ice-cap shall sweep down from the north pole upon these beautiful alpine flowers they will have to travel somewhere. There is manifestly as much necessity for them to get out of the way as for the rest of the flora. How will they manage to get down the mountains into the lowlands, and traverse uncongenial plains and deserts, to find other and far-distant alpine homes? They can never, of course, get very far away from the regions skirted by eternal frost, for their cup of joy must be chaliced by the snow-flake, or their beautiful life is soon ended. But if all our alpine flora have traveled from one evolutional centre, or have been "created but once in time and place," how have they managed to cross the thermal equator and spread themselves out over all the alpine regions of the globe? We call upon Mr. Darwin and Professor Gray to rise and explain. Not that we want any explanation, but that their theory of plant-migration stands sadly in need of one.

The theory which the Bible genesis suggests to us is fully adequate to the explanation wanted. It explains not only _why_ these alpine flora appear where they do, but why they cannot appear anywhere else. It also explains all the physiological facts to which we have referred in the foregoing chapters. Wherever the necessary alpine conditions exist the earth responds to the divine command, and the beautiful little alpine harebell is cradled into life, and rejoices in the bright embroidery it wears. And so, wherever streams are turned aside to flow through new meads and sheltered woods, or over broken and swaly places where cowslips never grew before, hardly a year will pa.s.s before this "wan flower" will hang therein "its pensive head," while all along the line of the stream the black alder will make its appearance in the lowlands, no matter how far its current may be diverted from its original channel, or how distant the supply of natural seeds. For nature's sternest painter can only delineate her as "instinct with music and _the vital spark_."

If our botanical professors would come forth into the true light of nature, they should accept the position of pupil to her, and not a.s.sert that of teacher. So long as they continue to peep and botanize upon her grave, or over ancient mounds and Hadrianic tumuli, they will never find out the cunning of her processes, much less the means she employs to accomplish her perfected ends. This modern idolatry of "hypotheses," with our chronic neglect of what nature _does_, is the great scientific stumbling-block of the age in which we live. Our botanists all agree that certain plants and trees disappear--hopelessly die out--from the _absence_ of "necessary conditions;" when will they come to recognize the reverse of this undeniable proposition, and agree that the _presence_ of necessary conditions may cause the same plants and trees to make their appearance, that is, spring into life in obedience to some great primal law, as unerringly obeyed by nature as the attractive force of the universe itself?

For nearly half a century the fact has been known that the geographical distribution of the European flora, and especially that of the British Islands, was referable to lat.i.tude, elevation, and climatic conditions. As early as 1835, Mr. Hewett Watson, a well-known botanist of that day, in his published "Remarks on the Geographical Distribution of Plants, in connection with Lat.i.tude, Elevation, and Climate," drew the attention of the botanical world to this remarkable feature of plant distribution; while the late Professor Edward Forbes pursued the same line of thought in his attempt to show how geographical changes had affected plant areas in Great Britain as far back as the last glacial drift. And yet all our botanical writers have been steadily persisting on immense plant-migrations to account for their geographical distribution, and have given us maps without number to show how the vegetal hosts have traversed vast continents, swam mult.i.tudinous seas, braved the fiery equator, and scaled the summits of the loftiest Andes. In the mean time, no botanist of any distinguished note, except M. De Candolle, has confidently ventured to question this migration theory, so imposing and formidable has been the array of names which have frowned down, like so many gigantic ghauts, upon the audacious questioner.

But the present actual state of knowledge on this subject forbids us any longer to accept theories for facts, premises for conclusions, or fallacious reasoning for legitimate induction. Truth and daylight never meet in a corner, and no one, in our day, need go to the bottom of a well in search of either. We are forever stumbling over the truth without knowing it, because our old traditional beliefs, like so many superannuated gra.s.shoppers, are constantly springing up in our path and diverting our attention from her. There are physiological facts enough daily obtruding themselves upon our attention, if we would but notice them, in the case of wayside plants, garden and household weeds, and the more aggressive vegetation of worn out pasture-lands, to satisfy us of the truth of our theory, were it not for the swarms of these old traditional gra.s.shoppers continually rising into the air before us, and shutting out the truth as it is in nature. And the worst feature about this whole business is, that we have come to regard these mult.i.tudinous insects as a delight instead of a burden.

But it is hardly necessary to pursue this subject further. We have shown, or shall show in the succeeding pages, that all crystalline forms come from necessary or favoring statical conditions; that all infusorial forms come in the same way, only their conditions may be said to be dynamical rather than statical; that all mycological forms (fungi) are dependent, for their primary manifestation, on conditions of moisture and decay; that all plant-life, from the lowest cryptogam to the lordliest conifer, is dependent on some similar incidence of conditions; that the mastodon, now only known by his fossil remains, must have wallowed forth from his "necessary mire" (plasmic conditions) in the Eocene period; and that all animal life must have come from some underlying law of primordial conditions, as impressed upon matter, in harmony with the "Divine Intendment" from the beginning; and that this law is still operative in the production of new forms of life whenever and wherever the same may appear. We shall also show that all living organisms, such as seeds, fungus-spores, morphological cells, etc., perish at a temperature of about 100A deg. C., and that _Bacteria, TorulA _, and other infusorial forms, making their appearance in super-heated flasks, originate not from morphological cells, plastide particles, bioplasts, or any other vital organism, but from indestructible vital units, which are everywhere present in the organic matter of our globe, and ready to burgeon forth into life whenever the necessary vital conditions exist, and the proper incidences of environment occur.

We have also shown that the earth still obeys the divine command to bring forth, or--if objection be made to this form of statement as unscientific--still obeys some inexorable underlying law tantamount to such command, and can no more help "bringing forth," when the necessary telluric conditions favor, than the cold can help coming out of the north, or the clouds dropping rain, when the necessary meteorological conditions occur. Give the future American botanist the physical geography of a country--its average rain-fall, temperature, etc., and the plant zone in which it lies, and, whether explored or unexplored, he will give us the general character of its vegetation, and name most of the plants and trees peculiar to its soil. And he will do this, not because he has any faith in the present theories of plant-migration, nor in the necessary distribution of seeds, but because he will study his favorite science with reference to lat.i.tude, elevation, climate, physical characteristics, rain-fall, soil-const.i.tuents, and other influencing conditions of plant-life.

But we will now proceed to consider the duration of vegetable species, for the purpose of showing that the evolutional changes they are undergoing, if any, must cover infinitely vaster periods of time than we have any data for determining, to say nothing of the unverified theories the evolutionists have been spinning for us.

Our geologic and paleontologic records are becoming richer in materials, more interesting in details, and more authentic in character, every year.

We are turning back page after page of these lithographic records, only to find the domain of science widened and deepened in interest as we advance, or as our rocks are being excavated, our mountains tunneled, our vast mines explored, and the beds of our rivers and arms of seas thoroughfared and traversed by the iron rail. Meanwhile, science exhibits signs of becoming less devoted to new-fangled theories, more exacting in her demands upon her votaries, and more eager to extend the domain of facts as the only true basis on which to rest her claims for future recognition. She is less dogmatic to-day than she was a year ago, and is likely to become less so a year hence than now. And this is largely due to her methods of research and inquiry. She is now everywhere sending out her hardier and more enthusiastic sons into new fields of exploration, to return laden with ampler materials to build, and richer treasures to adorn, a temple worthy of her name. In the field of the fossilized fauna and flora, these treasures are of the highest value and interest, all indicating not only wide areas of distribution, but immense periods of time, in which species have existed without any greater changes in character than the necessary shadings into varieties would seem to require. For nature everywhere characterizes her methods of production and reproduction by a loving tendency to diversify and variously adorn her species, as if to express the infinite conceptions of that power above her, which "spake and it was done, which commanded and it was brought forth."

From the fossilized plants of Atanekerdluk--a flora rich in species and wonderfully preserved in type--and the Miocene flora of Spitzenburg, to the southernmost limits of vegetation on the globe, science has reached out her hands for materials, and gathered them with as much success as avidity. And all scientific botanists agree in referring these fossilized forms from the high northern lat.i.tudes, to the Miocene period--one so remote that we can form no adequate conception of it, except as time may be measured by geologic periods. And these materials show that varieties of the _Sequoia_, the tulip-tree, oaks, beeches, walnuts, firs, poplars, hazelnuts, etc., etc., all flourished in these sub-arctic regions during the far-distant period we have named. Many of them must have grown on the spot where their trunks are now to be found, as their roots remain undisturbed in the soil, as well as at a time when these regions enjoyed a warm or cold temperate climate. Many of these fossilized and carbonized forms are identical with the living species of to-day, conclusively showing that neither natural variation, nor any secondary causes, have worked out any changes capable of being scientifically expressed in genetic value.

There is also abundant evidence to show that many of the present tropical forms flourished in central and southern Europe as far back as the warm inter-glacial epoch in the Eocene period. And if these inter-glacial periods occurred at the lowest minimum limits of eccentricity in the earth's...o...b..t, as calculated by Leverrier's formulA , we can have no conception whatever of the length of time actually intervening the period named and our present era. Mr. Croll has given us the limits of highest glaciation covering the last three million years, and shows that there have been but two periods of superior eccentricity in that time, and can be only one in the next million years, with but two or three intervening maxima and minima that may, or may not have been, of any special value. It is true that he a.s.signs importance to these maxima, as affecting possible glaciations, but there are other eminent astronomers and physicists who differ from him, and really attach little or no importance to these of any other intervening periods of eccentricity. If Mr. Croll is correct in his theory and estimates, we must separate these superior glacial epochs by an interval of not less than one million seven hundred thousand years; and nearly three of these periods must have intervened since some of the present tropical forms flourished in Europe. And if these forms have undergone no specific change in all this time, how many years will it require to work out even _one_ of Mr. Darwin's many evolutional changes?

The kins.h.i.+p between some of these arctic and sub-arctic fossilized flora and the living forms of to-day, is so near that they cannot be distinguished by a single difference. This is true of some of the varieties of the _Sequoia_ family, the oaks, beeches, firs, hazelnuts, etc., while others are so nearly identical that it would be difficult to cla.s.sify them as separate varieties. At all events, if they cannot be placed in the list of identical species, they cannot be ruled out of representative types. But why should our speculative botanists insist upon these "evolutional changes" in plant-life--these "derivative forms" of which they are constantly speaking? Paleontological botany has given us the very highest antiquity of species, and the most that can be claimed is that nature was just as prolific of diversified forms millions of years ago as now. Because we, by forcing nature into unnatural, if not repugnant, alliances, can produce

--"Streak'd gillyflowers, Which some call nature's b.a.s.t.a.r.ds."

it is no evidence that she commits any such offence against herself. Her alliances are all loving ones. She indulges in no forced methods of propagation. If she produced the _Sequoia gigantea_, or the great redwood tree of our California Sierra, as far back as the Crustaceous period, she has propagated it ever since according to her own loving methods, and it is idle to talk of the _Sequoia Langsdorfii_ as being the original ancestor of this tree, or any other distinguished branch of the sequoias.

How much more rational the suggestion of Professor Aga.s.siz that these trees--the entire family of sequoias--were quite as numerous in individual varieties at first as now, and that the fruit of the one can never bear the fruit of the other.

Again, take the still hardier and more numerous branches of the _Quercus_ or oak family. M. De Candolle has expended a vast deal of ingenuity to show that the various members of this old and ancestrally-knotty family have all descended from two or three of the hardier varieties. He arrives at this conclusion from a geographical survey of what he would call the "whole field of distribution," and "the probable historical connection between these congeneric species."

But science should deal with as few probabilities as possible, especially where experience furnishes no guide to certainty, and only the remotest clue to likelihood. We should never predicate probabilities except on some degree of actual evidence, or some likelihood of occurrence, falling within the limits, a.n.a.logically or otherwise, of human observation and experience. In no other way can we determine whether an event is probable or not. But here we have not so much as a probable experience to guide us. Geographical distribution in the past is hardly a safe criterion to go by, because we can never be absolutely certain that we have the requisite data on which to form a determinate judgment. The _Quercus robur_ may furnish the maximum test to-day, but a few concealed pockets of nature may bring some other variety of the congeneric species to the front to-morrow, requiring M.

De Candolle to correct his cla.s.sification. There are no less than twenty-eight varieties of this one species of oak, all of them conceded to be spontaneous in origin, and it has been on the earth quite as long as the more stately tribe of Sequoias. Besides, not more than one twenty-thousandth part of the earth's surface has been dug over to determine the extent to which any one of its varieties has flourished in the past.

Since these several varieties are only one degree removed from each other, M. De Candolle supposes divergence to be the natural law which has governed their growth, and not hereditary fixity. But here again he has only remote probabilities to work upon, no absolute data. We are still speaking of his fossilized herbaria, not his modern specimens. These may show a large number of genetically-connected individuals, or those claimed to be so connected. And yet no naturalist can be certain that, because they exhibit similarly marked characteristics, the one ever descended from the other; for the universal experience-rule still holds good that "like engenders like," and we search in vain for anything more than a similarity of _idea_, or logical connection, which justifies a recognition of the _individuorum similium_ in Jessieu's definition of species. But similarity must not be mistaken for absolute likeness, which nowhere exists in nature. Infinite diversity is the law, absolute ident.i.ty the rarest possible exception. No two oak leaves, for instance, in a million will be found actually alike, although taken from the same tree, or trees of the same variety; and the same may be said of the segmentation and branching of their limbs, as well as the striatures of their corticated covering, _Et sic de similibus_ everywhere, and with respect to every thing. Nature is more solicitous of diversity and beauty, than of similarity and tameness of effect, in all her landscape pictures; and the Platonic conception that "contraries spring from contraries," may be only a supplementary truth to that of _de similibus_. In the eye of the soul all objective existences are discerned in their logical order, or as consecutive thoughts of the Divine mind, as outspoken in the material universe. To insist upon cutting down these transcendental forms[20] into the smallest possible number of similar or identical forms, may be all well enough to accomplish scientific cla.s.sification; but the productive power of nature can never be limited by these mental processes of our own.

The oak family can be traced back to the Miocene period, and consequently enjoys quite as high an antiquity as the sequoias. Professor Gray, in speaking of the _Quercus robur_ and its probable origin, says that it is "traceable in Europe up to the commencement of the present epoch, looks eastward, and far into the past on far-distant sh.o.r.es." By "far-distant sh.o.r.es," he undoubtedly means Northwest America, where its remotest descendants still flourish. But that these trees should have waded the Pacific, or sent their acorns on a voyage of discovery after new habitats on the Asiatic coast, is hardly more probable than Jason's voyage after the golden fleece, in any other than a highly figurative sense. The spontaneous appearance of a forest of oaks on the eastern sh.o.r.es of Asia was just as probable, under favoring conditions--though occurring subsequently to the time of their appearance on this continent--as that of the miniature forests of "samphire," or small saline plants, which spontaneously made their appearance about the salt-works of Syracuse, when conditions actually favored. The high antiquity of the oak makes no difference in respect to the principle of dispersion, since geographical conditions are what govern, and not the theoretical considerations of the speculative botanist.

Mr. A. R. Wallace's formula concerning the origin of species, that they "have come into existence coincident both in time and place with preA"xisting closely-allied species," may or may not be true so far as individual localization is concerned. But it proves nothing in the way of original progeny, nor can we, by any actual data before us, satisfactorily determine, under this formula, which of the two closely-allied species preceded the other. If they came coincidently, both in time and place, their existence must have been concurrent, not separated by preA"xistence.

The formula may be true to this extent, that the conditions favoring the appearance of one species may have equally favored what we call a closely-allied species. But even in this case, the material sequence is lost, and we have nothing to express a relations.h.i.+p as from parent to progeny. For, however restricted as to localization, each species preserves its own characteristics, the similarities always being less than the dissimilarities. These, and other equally conclusive facts of observation, led Professor Aga.s.siz to question any necessary genetic connection between the different species, or between even the same species, in widely-separated localities; his idea being precisely that advanced by us in connection with the Bible genesis, that localization depended on geographical conditions, not on the migration of plants or the dispersion of seeds.