Was there one and only one first bit of protoplasm? If we were to say that life first appeared on the globe in Cambrian times, just what should we mean? That it began as a single point, or as many points? When we say that the primates first appeared in Eocene times, do we mean that one single primate appeared then? If so, what form went immediately before him? This is all a vain speculation.
Does man presuppose all the vertebrate sub-kingdom? Was he safe as long as one vertebrate form remained? Are his forebears many, and not one pair? Can we think of his ancestry under the image of a tree, and of him as one of the many branches? If so, nothing but the destruction of the tree would have imperiled his appearance, or the lopping off of his particular branch. Probably all such images are misleading. We simply cannot figure to ourselves the tangled course of our biological descent. If thwartings and accidents arid delays could have cut man off, how could he have escaped? We cannot think of man as one; we are compelled to think of him as many; and yet in all our experience the many come from the one, or the one pair.
How thick the field of animal life in the past is strewn with extinct forms!--as thick as the sidereal s.p.a.ces are strewn with the fragments of wrecked worlds! But other worlds and suns are spun out of the wrecked worlds and suns through the process of cosmic evolution. The world-stuff is worked over and over. Extinct animal forms must have given rise to other, allied forms before they perished, and these to still others, and so on down to our time.
The image of a tree is misleading from the fact that all the different branches of the animal kingdom, from the protozoa up to man, have come along with what we call the higher branches, the mammals; the suckers have kept pace with the main stalk, so that we have the image of a sheaf of branches starting from a common origin and all of equal length. Man has brought on his relations along with him.
There is no glamour of romance over that past. It was all hard, prosy, terrible fact. The earth"s crust was less stable than now, the upheavals and subsidences and earthquakes more frequent, the warring of the elements more fierce and incessant, deluge and inundation in more rapid succession, and the riot and excesses of animal life far beyond anything we know of. And our line of descent was taking its chances amid it all. The widespread blotting out of life at the end of Palaeozoic time, and again at the end of Mesozoic times, when myriads of forms were cut off, probably from some convulsion of nature or some cosmic catastrophe; and again during the ice age, when the camel, the llama, the horse, the tapir, the mastodon, the elephant, the giant sloth, became extinct in North America--how fared it with our ancestor during these terrible ages?
There is no sure trace of him till late Tertiary times, and it is probably not more than two hundred thousand years ago that he a.s.sumed the upright att.i.tude and began to use tools. Probably in Europe fifty thousand years ago he was living in caves, clothed in skins, contending with the cave bear and cave lion, using rude stone implements, and hunting the hairy mastodon, etc. In Asia the probabilities are that he was farther on the road toward the dawn of history.
We may think of our descent in the historic period under the image of the stream, though of a stream many times delayed and diverted, even many times diminished by wars and plagues and famine, but a stream with some sort of unity and continuity, since man became man.
The stream of life is like any other stream in this respect. Divert or use up part of the water of a stream, yet what is left flows on and keeps up the continuity and ident.i.ty of the stream; dip your cup into it here, and you will not get precisely the same water you would have got had none of it been diverted or used far back in its course--you get the water that was allowed to flow by.
Had there been no loss of life by war and pestilence and accidents of various kinds, the different countries would have been occupied by quite other men and women than those that fill them to-day. The course of life in every neighborhood is changed by what seem like accidental causes, as when a family is practically wiped out by some accident or dread disease. This brings new people on the scene. The farm or the business falls into other hands, and new social relations spring up, new men and women are brought together or the old ones driven apart, marriage is hastened or r.e.t.a.r.ded, opportunities for family life are made or unmade, and fewer children, or more children, as the case may be, are the result. The issue of some battle hundreds or thousands of years ago may have played a part in your life and mine to-day--other races, other individuals of the race, would have been thrown together had the issue been different, and other families started, so that some one else would have been here in our stead.
But the question of hazard to the race of man in geologic time is quite a different one. Here our fate seems to hang by a single thread--a golden thread, we may call it, but, in that terrible maze of clashing forces and devouring forms of the vast geologic periods, how liable to be broken! It is not now a question of the continuity of a stream, but of the continuity of a single evolutionary process, or, as Haeckel says, the continuity of the morphological chain which stretches from the lemurs up through tailed and tailless anthropoid apes to man. If the evolutionary impulse had been checked or extinguished in the lemur--that small apelike animal that went before the true ape, the fossil remains of which have been found on this continent and the survivals of which are now found in Madagascar--would man have appeared? Again, if the race of lemurs developed from a single pair, how precarious seems our fate! In fact, if any of the transitional forms between species can be reduced to a single pair--as the forms that connect the reptiles with the mammals--our fate would seem to be in the keeping of these forms. Over this single frail bridge which escaped the floods and the tornadoes and the earthquakes of those terrible ages we must have pa.s.sed. What risky business it all seems! Was it luck or law that favored us? Doubtless, if we could penetrate the mystery, we should see that there was no chance or risk in the matter. We cannot go very far in solving these great fundamental questions by applying to them the tests of our own experience, Numberless specific forms become extinct, but the impulse that begat the form does not die out. Thus, all the giant reptiles died out--the dinosaurs, the mesosaurs--but the reptilian impulse still survives. How many types of invertebrates have perished! but the invertebrate impulse still goes on. How many species of mammals have been cut off! yet the mammal impulse has steadily gone forward. These things suggest the wave that moves on but leaves the water behind. The vertebrate impulse began in wormlike forms, in the old Palaeozoic seas, and stopped not till it culminated in man. This impulse has left many forms behind it; but has this impulse itself ever been endangered?
If one looks at the matter thus in an abstract instead of a concrete way, the problem of our descent becomes easier.
When we look at the evolution of life on a grand scale, nature seems to feel her way, like a blind man, groping, hesitating, trying this road and then that. In some cases the line of evolution seems to end in a cul de sac beyond which no progress is possible. The forms thus cornered soon become extinct. The mystery, the unaccountable thing, is the appearance of new characters. The slow modification or transformation of an existing character may often be traced; natural selection, or the struggle for existence, takes it in hand and adapts and perpetuates it, or else eliminates it. But the origin of certain new parts or characters--that is the secret of the evolutionary process. Thus there was a time when no animal had horns; then horns appeared. "In the great quadruped known as t.i.tanothere," says...o...b..rn, "rudiments of horns first arise independently at certain definite parts of the skull; they arise at first alike in both s.e.xes, or as.e.xually; then they become s.e.xual, or chiefly characteristic of males; then they rapidly evolve in the males while being arrested in development in the females; finally, they become in some of the animals dominant characteristics to which all others bend." Nature seems to throw out these new characters and then lets them take their chances in the clash of forces and tendencies that go on in the arena of life. If they serve a purpose or are an advantage, they remain; if not, they drop out. Nature feels her way. The horns proved of less advantage to the females than to the males; they seem a part of the plus or overflow of the male principle, like the beard in man--the badge of masculinity. The t.i.tanothere is traceable back to a hornless animal the size of a sheep, and it ended in a horned quadruped nearly as large as an elephant. It flourished in Wyoming in early Tertiary times. Nature did not seem to know what to do with horns when she first got them.
She played with them like a child with a new toy. Thus she gave two pairs to several species of mammals, one pair on the nose and one pair on the top of the skull--certainly an embarra.s.sment of weapons.
The first horns appear to have been crude, heavy, uncouth, but long before we reach our own geologic era they appear in various species of quadrupeds, and become graceful and ornamental. How beautiful they are in many of the African antelope tribe! Nature"s workmanship nearly always improves with time, like that of man"s, and sooner or later takes on an ornamental phase.
The early uncouth, bizarre forms seem to be the result of the excess or surplus of life. Life in remote biologic times was rank and riotous, as it is now, in a measure, in tropical lands. One reason may be that the climate of the globe during the middle period, and well into the third period, appears to have been of a tropical character. The climatic and seasonal divisions were not at all p.r.o.nounced, and both animal and vegetable life took on gigantic and grotesque forms. In the ugliness of alligator and rhinoceros and hippopotamus of our day we get some hint of what early reptilian and mammalian life was like.
That Nature should have turned out better and better handiwork as the ages pa.s.sed; that she either should have improved upon every model or else discarded it; that she should have progressed from the bird, half-dragon, to the sweet songsters of our day and to the superb forms of the air that we know; that evolution should have entered upon a refining and spiritualizing phase, developing larger brains and smaller bodies, is a very significant fact, and one quite beyond the range of the mechanistic conception of life.
Our own immediate line of descent leads down through the minor forms of Tertiary and Mesozoic times--forms that probably skulked and dodged about amid the terrible and gigantic creatures of those ages as the small game of to-day hide and flee from the presence of their arch-enemy, man; and that the frail line upon which the fate of the human race hung should not have been severed during the wild turmoil of those ages is, to me, a source of perpetual wonder.
III
The hazards of the future of the race must be quite different from those I have been considering. They are the hazards incident to an exceptional being upon this earth--a being that takes his fate in his own hands in a sense that no other creature does.
Man has partaken of the fruit of the Tree of Good and Evil, which all the lower orders have escaped. He knows, and knows that he knows. Will this knowledge, through the opposition in which it places him to elemental nature and the vast system of artificial things with which it has enabled him to surround himself, cut short his history upon this planet? Will Nature in the end be avenged for the secrets he has forced from her? His civilization has doubtless made him the victim of diseases to which the lower orders, and even savage man, are strangers. Will not these diseases increase as his life becomes more and more complex and artificial? Will he go on extending his mastery over Nature and refining or suppressing his natural appet.i.tes till his original hold upon life is fatally enfeebled?
It seems as though science ought to save man and prolong his stay on this planet,--it ought to bring him natural salvation, as his religion promises him supernatural salvation. But of course, man"s fate is bound up with the fate of the planet and of the biological tree of which he is one of the shoots. Biology is rooted in geology.
The higher forms of life did not arbitrarily appear, they flowed out of conditions that were long in maturing; they flowered in season, and the flower will fall in season. Man could not have appeared earlier than he did, nor later than he did; he came out of what went before, and he will go out with what comes after. His coming was natural, and his going will be natural. His period had a beginning, and it will have an end. Natural philosophy leads one to affirm this; but of time measured by human history he may yet have a lease of tens of thousands of years.
The hazard of the future is a question of both astronomy and geology. That there are cosmic dangers, though infinitely remote, every astronomer knows. That there are collisions between heavenly bodies is an indubitable fact, and if collisions do happen to any, allow time enough and they must happen to all. That there are geologic dangers through the shifting and crumpling of the earth"s crust, every geologist knows, though probably none that could wipe out the whole race of man. The biologic dangers of the past we have outlived--the dangers that must have beset a single line of descent amid the carnival of power and the ferocity of the monster reptiles of Mesozoic times, and the wholesale extinction of species that occurred in different geologic periods.
Nothing but a cosmic catastrophe, involving the fate of the whole earth, could now exterminate the human race. It is highly improbable that this will ever happen. The race of man will go out from a slow, insensible failure, through the aging of the planet, of the conditions of life that brought man here. The evolutionary process upon a cooling world must, after the elapse of a vast period of time, lose its impetus and cease.
XIII
THE GOSPEL OF NATURE
I
The other day a clergyman who described himself as a preacher of the gospel of Christ wrote, asking me to come and talk to his people on the gospel of Nature. The request set me to thinking whether or not Nature has any gospel in the sense the clergyman had in mind, any message that is likely to be specially comforting to the average orthodox religious person. I suppose the parson wished me to tell his flock what I had found in Nature that was a strength or a solace to myself.
What had all my many years of journeyings to Nature yielded me that would supplement or reinforce the gospel he was preaching? Had the birds taught me any valuable lessons? Had the four-footed beasts?
Had the insects? Had the flowers, the trees, the soil, the coming and the going of the seasons? Had I really found sermons in stones, books in running brooks and good in everything? Had the lilies of the field, that neither toil nor spin, and yet are more royally clad than Solomon in all his glory, helped me in any way to clothe myself with humility, with justice, with truthfulness?
It is not easy for one to say just what he owes to all these things.
Natural influences work indirectly as well as directly; they work upon the subconscious, as well as upon the conscious, self. That I am a saner, healthier, more contented man, with truer standards of life, for all my loiterings in the fields and woods, I am fully convinced.
That I am less social, less interested in my neighbors and in the body politic, more inclined to shirk civic and social responsibilities and to stop my ears against the brawling of the reformers, is perhaps equally true.
One thing is certain, in a hygienic way I owe much to my excursions to Nature. They have helped to clothe me with health, if not with humility; they have helped sharpen and attune all my senses; they have kept my eyes in such good trim that they have not failed me for one moment during all the seventy-five years I have had them; they have made my sense of smell so keen that I have much pleasure in the wild, open-air perfumes, especially in the spring--the delicate breath of the blooming elms and maples and willows, the breath of the woods, of the pastures, of the sh.o.r.e. This keen, healthy sense of smell has made me abhor tobacco and flee from close rooms, and put the stench of cities behind me. I fancy that this whole world of wild, natural perfumes is lost to the tobacco-user and to the city- dweller. Senses trained in the open air are in tune with open-air objects; they are quick, delicate, and discriminating. When I go to town, my ear suffers as well as my nose: the impact of the city upon my senses is hard and dissonant; the ear is stunned, the nose is outraged, and the eye is confused. When I come back, I go to Nature to be soothed and healed, and to have my senses put in tune once more. I know that, as a rule, country or farming folk are not remarkable for the delicacy of their senses, but this is owing mainly to the benumbing and brutalizing effect of continued hard labor. It is their minds more than their bodies that suffer.
When I have dwelt in cities the country was always near by, and I used to get a bite of country soil at least once a week to keep my system normal.
Emerson says that "the day does not seem wholly profane in which we have given heed to some natural object." If Emerson had stopped to qualify his remark, he would have added, if we give heed to it in the right spirit, if we give heed to it as a nature-lover and truth-seeker. Nature love as Emerson knew it, and as Wordsworth knew it, and as any of the choicer spirits of our time have known it, has distinctly a religious value. It does not come to a man or a woman who is wholly absorbed in selfish or worldly or material ends.
Except ye become in a measure as little children, ye cannot enter the kingdom of Nature--as Audubon entered it, as Th.o.r.eau entered it, as Bryant and Amiel entered it, and as all those enter it who make it a resource in their lives and an instrument of their culture. The forms and creeds of religion change, but the sentiment of religion--the wonder and reverence and love we feel in the presence of the inscrutable universe--persists. Indeed, these seem to be renewing their life to-day in this growing love for all natural objects and in this increasing tenderness toward all forms of life.
If we do not go to church so much as did our fathers, we go to the woods much more, and are much more inclined to make a temple of them than they were.
We now use the word Nature very much as our fathers used the word G.o.d, and, I suppose, back of it all we mean the power that is everywhere present and active, and in whose lap the visible universe is held and nourished. It is a power that we can see and touch and hear, and realize every moment of our lives how absolutely we are dependent upon it. There are no atheists or skeptics in regard to this power. All men see how literally we are its children, and all men learn how swift and sure is the penalty of disobedience to its commands.
Our a.s.sociations with Nature vulgarize it and rob it of its divinity. When we come to see that the celestial and the terrestrial are one, that time and eternity are one, that mind and matter are one, that death and life are one, that there is and can be nothing not inherent in Nature, then we no longer look for or expect a far-off, unknown G.o.d.
Nature teaches more than she preaches. There are no sermons in stones. It is easier to get a spark out of a stone than a moral.
Even when it contains a fossil, it teaches history rather than morals. It comes down from the fore-world an undigested bit that has resisted the tooth and maw of time, and can tell you many things if you have the eye to read them. The soil upon which it lies or in which it is imbedded was rock, too, back in geologic time, but the mill that ground it up pa.s.sed the fragment of stone through without entirely reducing it. Very likely it is made up of the minute remains of innumerable tiny creatures that lived and died in the ancient seas. Very likely it was torn from its parent rock and brought to the place where it now lies by the great ice-flood that many tens of thousands of years ago crept slowly but irresistibly down out of the North over the greater part of all the northern continents.
But all this appeals to the intellect, and contains no lesson for the moral nature. If we are to find sermons in stones, we are to look for them in the relations of the stones to other things--when they are out of place, when they press down the gra.s.s or the flowers, or impede the plow, or dull the scythe, or usurp the soil, or shelter vermin, as do old inst.i.tutions and old usages that have had their day. A stone that is much knocked about gets its sharp angles worn off, as do men. "A rolling stone gathers no moss," which is not bad for the stone, as moss hastens decay. "Killing two birds with one stone" is a bad saying, because it reminds boys to stone the birds, which is bad for both boys and birds. But "People who live in gla.s.s houses should not throw stones" is on the right side of the account, as it discourages stone-throwing and reminds us that we are no better than our neighbors.
The lesson in running brooks is that motion is a great purifier and health-producer. When the brook ceases to run, it soon stagnates. It keeps in touch with the great vital currents when it is in motion, and unites with other brooks to help make the river. In motion it soon leaves all mud and sediment behind. Do not proper work and the exercise of will power have the same effect upon our lives?
The other day in my walk I came upon a sap-bucket that had been left standing by the maple tree all the spring and summer. What a bucketful of corruption was that, a mixture of sap and rainwater that had rotted, and smelled to heaven. Mice and birds and insects had been drowned in it, and added to its unsavory character. It was a bit of Nature cut off from the vitalizing and purifying chem- istry of the whole. With what satisfaction I emptied it upon the ground while I held my nose and saw it filter into the turf, where I knew it was dying to go and where I knew every particle of the reeking, fetid fluid would soon be made sweet and wholesome again by the chemistry of the soil!
II