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Adventures of a Grain of Dust

<h2>CHAPTER X</h2> (OCTOBER) <blockquote>It is hardly an exaggeration to say that the tip of a root acts like the brain of the lower animals. —Darwin. </blockquote> <h3>THE BUSY FINGERS OF THE ROOTS</h3> This has been a very busy season for Mr. Root and his family. It always is, and you can imagine they're all glad when Fall comes and they can lay by for the Winter. "There's your apple crop, I helped make that," Mr. Root might say. "And there's the corn and the wheat in the granary, and the rye and the oats and the barley; and the hay in the mow; and the pumpkins and the carrots, and the turnips, and the potatoes in the root cellar; and the jelly in the jelly-glasses, and the jam, and the preserves—we[Pg 187] helped make them all. "And we've been working for you almost since the world began; almost, but not quite—for the earliest plants, the Lichens, for example—didn't have true roots. "Yes, and—well, I don't want to say anything—Mr. Lichen has been a good neighbor—but he never did amount to much; never could. No plant can amount to much without roots. But with roots and a good start a plant can do almost anything—raise flowers and fruit and nuts, and help grow trees so tall you can hardly see the tops of them. And, it isn't alone what we do for the plants we belong to, but for the soil, for other plants and roots that come after we're dead and gone. For them we even split up rocks, and so start these rocks on their way to becoming soil." <h4>I. All in the Day's Work</h4> It's a fact. Roots do split rocks. Hundreds of times I've been in the cracks of rocks that were split in that way. I mean right when the splitting was going on. This happened oftenest where trees grew on the stony flanks of mountains. Seeds of the pines, say, dropped in crevices by the wind, sprout in the soil they find there, and then, as these shoots grow up into trees, the enlarged roots, in their search for more soil, thrust themselves deeper and deeper into the original lodging-place, and so split even big rocks. The tap-roots do the heaviest part of this pioneer work. After the older and larger roots have broken up the rock, the smaller roots and fibres, feeling their way about among the stones, enter the smaller openings and[Pg 188] by their growth divide the rock again and again. But it's a lot of hard work for little return, so far as these early settlers are concerned; just a bare living. All these rock fragments, in the course of the years, become soil, but the amount of decay is small in the lifetime of the tree that does the breaking. A root, as you doubtless know, tapers. This enables it to enter a rock crevice like a wedge. As it pushes its way in farther and farther it is growing bigger and bigger, and it is this steady pressure that breaks the rock. Even the tiny root of a bean grows with a force of several pounds, and the power exerted by the growth of big roots is something tremendous. At Amherst Agricultural College, one time, they harnessed up a squash to see how hard it could push by growing. From a force of sixty pounds, when it was a mere baby, what do you suppose its push amounted to when it had reached full squashhood in October? Nearly 5,000 pounds; over two tons! <div class="figcenter"><div class="figborder"> <ANTIMG src="images/i201.jpg" alt="" /> HOW A LITTLE ROOT SPLIT A GRANITE BLOCK The little winged seed from which this pine-tree grew was carried by the wind one day into a tiny crack in that big granite block. As the treelet grew the tap root split the rock, penetrated to the earth below and fed the trunk until it became, as you see, a tree 40 feet high and 18 inches in diameter! </div> </div> But don't think because roots can and do split rocks, if need be, that they go about looking for such hard work. On the contrary. In travelling through the soil they always choose the easiest route, the softest spots. They use their brains as well as their muscles, and what they do with these brains is almost unbelievable. Yet the roots are such modest, retiring folks, always hiding, that it was a long time before the wise men—the science people—found out what all they do. It took a lot of science people and the wisest—including the great Darwin—to get the story, and they haven't got it all yet, as you will see. It was Darwin who first thought of having Mr. Root write out his autobiography—or part of it—the[Pg 189] story of his travels; for he does travel, not only forward—as everybody knows—but around and around. A regular globe-trotter! <div class="figcenter"><div class="figborder"> <ANTIMG src="images/i202.jpg" alt="" /> WHY BABY PLANTS BACK INTO THE WORLD Most plants back into the world out of the seed like that. Why? To protect their tender first leaves. Suppose you were taking some very valuable thing, easily injured—baby brother, say—through a swinging door and you had to use both hands to carry him. You wouldn't open the door by pushing that dear, little tender head of his against it, would you? You'd open it by backing through. </div> </div> Mr. Darwin was a wonderful hand at that sort of thing—getting nature people to tell their stories. He was an[Pg 190] inventor, like Mr. Edison; only, instead of inventing telephones for human beings to talk with, he invented ways of talking for nature people. You saw how he fixed it so that the earthworms could tell what they knew about geometry and botany. Well, in the case of the roots, what did he do one day but take a piece of glass, smoke it all over with lampblack—you'd have thought he was going to look at an eclipse—and then set it so that Mr. Root could use it as a kind of writing-desk. In a hitching, jerky sort of way roots turn round and round as they grow forward. In the ground, to be sure, a root can't move as freely nor as fast as it did out in the open and over this smooth glass, but it does turn, slowly, little by little. The very first change in a growing seed is the putting out of a[Pg 191] tiny root, and from the first this root feels its way along, like one trying to find something in a dark room. Thus it searches out the most mellow soil and also any little cracks down which it can pass. <div class="figright"> <ANTIMG src="images/i203.jpg" alt="" /> CHARLES DARWIN The great naturalist. </div> "Here's a fine opening for a live young chap," we can imagine one of these roots saying when it comes to an empty earthworm's burrow or a vacancy left by some other little root that has decayed and gone away. Roots always help themselves, when they can, to ready-made openings, and it is this round-and-round motion that enables them to find these openings. But even this isn't all. A root not only moves forward and bends down—so that it may always keep under cover and away from the light—but it has a kind of rocking motion, swinging back and forth, like a winding river between its banks, and for a somewhat similar reason. "It's looking for a soft spot!" says the high school boy, "just as the river does." <h5>NO HIT-OR-MISS METHODS FOR MR. ROOT</h5> Exactly. But not in the sense that this phrase is used in slang. The root has certain work to do, and it does it in the quickest and best way. It can get food more quickly[Pg 192] out of mellow soil than out of hard, and so it constantly hunts it up. I mean just that—hunts it up. For it isn't by aimless rocking back and forth that roots just happen upon the mellow places. It's the other way around; it's from a careful feeling along for the mellow places that the rocking motion results. "But how on earth do the roots do this? What makes them do it?" That's what any live boy would ask, wouldn't he? So you may be sure that's what the science people asked, and this is the answer: The roots, like all parts of the plant—like all parts of boys and girls and grown people, for the matter of that—are made up of little cells. Well, these cells, first on one side of the root and then the other, enlarge, and so pump in an extra flow of sap. Now, as we know, the sap contains food for the plant, just as blood contains food for our bodies; and more food means more growth. So the side of the root where the cells first swell out grows fastest and thus pushes the root over on the opposite side. Then the cells on this opposite side swell, and the root is turned in the other direction again. So it goes—right and left, up and down. And when these two motions—the up and down and right and left—are put together, don't you see what you get? The round-and-round motion! Precisely the same thing happened right now when you turned your finger round and round to imitate the motion of the root. (I saw you!) The muscles that did the work swelled up first on one side and then on the other, just as they do when you bend your elbow, when you walk, when you breathe, when you laugh. And more than that: You know how tired you get if[Pg 193] you keep using one set of muscles all the time—in sawing fire-wood, for example. Yet you can play ball by the hour and never think of being tired until it's all over; because, for one thing, you are constantly bringing new muscles into action as you go to bat, as you strike, as you run bases. It's the same way with the roots, it seems. For the theory is that after the cells on one side have swelled, they rest; then the cells on the other side get to work. "But what starts the movement?" you may say. "The idea of moving my arms and legs starts in my brain." <h5>WHERE MR. ROOT KEEPS HIS BRAINS</h5> Just so again. The root has a brain, too, or what answers for a brain. And the root's brain, is in its head; at least in the vicinity of its nose—that is to say, its tip. It's the tip that first finds out which side of the road is best, and passes the word back to the part of the root just behind it to bend this way or that. It's also the tip that feels the pull of gravity and knows that it's the business of roots to keep under cover. And Mr. Root just will have it that way! You can't change his mind. Mr. Darwin tried it and he couldn't; although he finally changed human people's minds a lot. <div class="figright"> <ANTIMG src="images/i205.jpg" alt="" /> WHERE MR. ROOT WEARS HIS CAP A root wears its cap right where you do—over its brain department; that is to say, the tip. It is called the "root cap" and protects the tip from injury. </div> This is how he tried it on a root. He took a bean with a little root that had just started out into the world. He cut off the tip and then set the bean so that the root stuck straight up. It continued to grow that way for some little[Pg 194] time. Finally, however, a new tip had formed. Then there was a general waking up, as if the tip said to the rest of the root: "Here, here, this will never do! Where are you going? You must bend down!" Anyhow that's what the root proceeded to do. One side seemed to stop growing, almost, while the other side grew rapidly and so the bending was done. "Did you ever! But how does the tip send back word?" "Don't ask me!" says the science man; say all the science men, even to this day. "We don't know yet just how it's done. But we're studying these things all the time, and we'll know more about it by and by. Meanwhile, perhaps you'll tell us why you say 'ouch' and pull your finger away when you touch something hot." "Oh," you reply, "I say 'ouch' because it hurts; and teacher and the Physiology say my arm pulls my hand away because my head tells it to." "Yes, but how does the head make the arm do the pulling? What's the connection?" says the science man. Well, I guess we'll have to tell him we don't know, won't we? But all the root's brains aren't in the tip, any more than all our brains are in our heads. Scattered through our bodies, you know, are little brains, the ganglia, that control different parts of the body. So it is with roots. For instance, a root at a short distance from the tip, is sensitive to the touch of hard objects in such a way that it bends toward them instead of turning away, as the tip does. The result is that when a root comes to a pebble, say, under ground, the sides of the root press close up to the sides of[Pg 195] the pebble—turn around corners sharply, by the shortest route—and so get over the obstruction as soon as possible and resume their course in the soil. <div class="figcenter"><div class="figborder"> <ANTIMG src="images/i207.jpg" alt="" /> BUT THEY COULDN'T CHANGE ITS MIND Some sprouting seedlings were attached to a disk like that, and when the roots started to grow down, the disk was turned to make them point upwards. But, no Sir! The roots just wouldn't grow upward. They turned downward. Every time! </div> </div> And different parts of a plant's root system respond in different ways to the pull of gravity, and some don't respond at all. The tap-root, for example, which always grows down, has roots growing out from it horizontally. They just won't grow any other way, and yet this is also supposed to be due to the influence of gravity. Then, from these horizontal roots, grow out a third set, and they don't seem to pay any attention whatever to gravity. They grow out in all directions—every which way—so that if there is a bit to eat anywhere in the neighborhood they are reasonably sure to find it. You see it works out all right. When a plant first begins to peep into the world out of that wonder box we call the seed, it's the root, as we know, that does the peeping; it comes first. And its first business[Pg 196] is to get a firm hold in the soil. So a lot of fine hairlike fibres grow right and left and all around and take a firm grip. There is an acid in the root that dissolves whatever the root touches that has any food in it—including pebbles and old bones—and so makes a kind of sticky stuff that hardens. In this way these fibrous roots not only get good meals for themselves and the rest of the plant, but they hold the plant firmly in the soil, against the strain of the winds. They also give the tap-root something to brace its back against, as it were, while it pushes down for water, for the moisture in the damper portion of the soil beneath. As you may have noticed, a seed merely lying loose on the ground is lifted up by its first little root in its effort to poke its nose into the soil. But Nature makes provisions for covering seeds up. They are covered by the castings of the earthworms, the dirt thrown out by burrowing animals and scratching birds. Some seeds fall into cracks where the ground is very dry and others are washed into them by the rains; while these as well as seeds lying on the surface are covered by the washings of the rain. Then come the roots that grip the soil. Always growing just back of the tip, are thousands of root-hairs, as fine as down. These get food from the soil. They soon disappear from the older parts of the root, so that it stops gathering food itself and puts in all its time passing along to the stem and leaves the food gathered by the finer and younger roots. This is why plants are so apt to wilt if you aren't careful when transplanting them; the root-hairs get broken off. For the same reason, corn, after it grows tall, is not ploughed deeply. The fine roots reach[Pg 197] out between the rows and the ploughshare would cut them off. <h4>II. Mr. Root's Presence of Mind</h4> All these things and more the roots do in their daily work—in the ordinary course of business. And it's wonderful enough. Don't you think so? But there are even stranger things to tell; things that would almost make us believe roots have what in human beings we call "presence of mind." That is to say, the faculty of thinking just what to do when something happens that one isn't looking for; when the house takes fire, for example, or the baby upsets the ink. <div class="figcenter"><div class="figborder"> <ANTIMG src="images/i209.jpg" alt="" /> THREE SCHOOLS OF STRATEGY </div> </div> <h5>A ROOT'S WAY OF CROSSING A ROAD</h5> Take the case of tree roots crossing a country road for a drink of water. They do it just as you or I would, I'll be bound. Just suppose you and I were roots of a big tree[Pg 198] that wanted to reach the moist bank of a stream, and there was a hard road-bed between. We can't go over the top, and the road-bed is so hard we can't go straight through on our natural level so we'll just stoop down and go under, won't we? That's exactly what the roots do. They dip down until they get under the hard-packed soil, and then up they come again on the other side and into the moist bank they started for. The roots of each kind of plant or tree have their natural level; that's one reason, as we know, why so many different kinds of plants—grass, trees, bushes, and things—get on so well together in the fields and woods. The tree roots that we have just seen crossing the road only went down below their natural level because they had to, as if the tip said: "This soil is too hard. We can never get through. Bend down! Bend down!" So the roots bent down until they came to softer soil, then forward, but always working up toward their natural level, and so it was at their natural level they came out on the other side. <h5>A ROOT'S STRANGE ADVENTURE WITH A SHOE</h5> But here's an example of "presence of mind," that nobody has accounted for. A good-sized root, working along through the soil, like Little Brother Mole, to earn its board and keep, came right up against the sole of somebody's old shoe that had got buried in the soil. In the sole were a lot of holes where the stitches used to be. The root divided into many parts, and many of these smaller roots found their way through the stitch holes. Then, coming[Pg 199] out on the other side, these little roots got together and travelled on, side by side! <div class="figcenter"><div class="figborder"> <ANTIMG src="images/i211a.jpg" alt="" /> HOW THE RAG BABIES TELL THE FORTUNE OF THE SEED CORN In what is popularly called "the Rag Baby Test" the seed corn is placed on squares marked on cloth with numbers corresponding to the numbered ears. Then they are rolled up in one of those moistened rags until they sprout. </div> </div> Isn't that a story for you? But there's no accounting for it. As we have seen, the men of science know a little bit about how a root manages to turn round and round and away from the light and so on, but what kind of machinery or process is it that could tell the root if it would[Pg 200] split up into little threads it could get through the stitch holes in that old boot? You can't imagine; at least, nobody so far has thought how it was done. But it's all true. We'll find the story and a lot of other things about the ways of roots in one of the books we'll get acquainted with when we come to the "Hide and Seek." <div class="figcenter"><div class="figborder"> <ANTIMG src="images/i211b.jpg" alt="" /> © International Harvester Company THIS IS THE ANSWER The seed from Ear No. 12 came out beautifully, didn't it? That from Ear No. 13 looks as if they were superstitious in Corn Land; but of course it was the fault of the seed and not of the number. </div> </div> Here's another example of the same thing; what we have called "presence of mind," resourcefulness, invention. This example is even more striking, if possible, because, for one thing, it is a case where roots still more completely altered their habits to save a tree struggling for its life on a stony mountain cliff. Maeterlinck tells about it in his picturesque and dramatic style. The subject—the hero, as it were—of this story was a laurel-tree growing on some cliff above a chasm at the bottom of which ran a mountain torrent. <blockquote>"It was easy to see in its twisted and, so to say, writhing trunk, the whole drama of its hard and tenacious life. The young stem had started from a vertical plane, so that its top, instead of rising toward the sky, bent down over the gulf. It was obliged, therefore, notwithstanding the weight of its branches, stubbornly to bend its disconcerted trunk into the form of an elbow close to the rock, and thus, like a swimmer who throws back his head, by means of an incessant will, to hold the heavy leaves straight up into the sky." </blockquote> This bent arm, in course of time, struggling with wind and storm, grew so that it swelled out in knots and cords, like muscles upholding a terrific burden. But the strain finally proved too much. The tree began to crack at the elbow and decay set in. <blockquote>"The leafy dome grew heavier, while a hidden canker gnawed[Pg 201] deeper into the tragic arm that supported it in space. Then, obeying I know not what order of instinct, two stout roots, issuing from the trunk at some considerable distance above the elbow, grew out and moored it to the granite wall." </blockquote> As if the roots, naturally so afraid of light, had heard a frantic call for help and, regardless of everything, had come to the rescue. To be sure, certain roots—the prop-roots of corn-stalks, for instance, as you have noticed—habitually reach from above ground down into the soil, and serve to brace the tall stem swaying in the winds, but trees usually have no such roots and no such habits. Yet, here a tree seems suddenly to have learned, somehow, that elsewhere in the land of plants this thing is done. But how did it learn it? Did the brownies or the gnomes tell it; or was it some of the spirits of the wind that go everywhere and see everything? It might have been the same wind sprites that carry the seeds of the laurel and the pine so far up the mountain flanks. Or it might have been the dryads, those beautiful creatures of the wood the Greeks knew so much about. I tell you there are some mighty queer things going on in the plant world, and perhaps Bud was right! <div class="poem"><div class="stanza"> "Some peoples thinks they ain't no Fairies now, No more yet! But they is, I bet!" </div> </div> HIDE AND SEEK IN THE LIBRARY <blockquote>And, what is more, real live fairies have been found right down in the world of roots! The science people call them "Bacteria," but what of that? The thing about a fairy that makes it a fairy is that it is always changing something into something else. Isn't[Pg 202] that right? Well, that's exactly what is done by the bacteria on the roots of certain kinds of plants—clover roots, for one; and the roots of beans, peas, peanuts, and alfalfa. These plants belong to the legume family, and if you will look up the word Legumes you will find out all about these fairy factories on the roots. Among other things you'll learn how small these fairies are. Why, 100,000 of the bacteria that live on clover roots, marching single file, wouldn't much more than reach across this typed page.[24] And in their little "villages" on one system of clover roots there are so many that all of them put together would make a city as big as London or New York; if the bacteria were as big as people, I mean. Of course you have to take a microscope to see them—a very powerful microscope—and even then some kinds of bacteria you can't see until you put colored clothes on them. (Every high school boy who has worked in the "lab" knows how this is done.) And when you finally see them, a strange thing happens. You've hardly got your eye on a little Mr. Bacteria before he's two! "What's this! What's this!" you say. "Am I seeing double?" You look again and he's four! But don't be alarmed, you aren't seeing double; it's just the little Mr. Bacterias multiplying by division. How they multiply by division is one of the interesting things you can learn by looking them up. But it's a good thing that the bacteria people in the little nitrogen factories on the clover roots can get more farm-hands in this way, for they have a lot to do, and their work is one of the most interesting things that goes on about the place. The article in the "Country Life Reader" on "The Smallest Plant on the Farm" will tell you how important these nitrogen farmers are. You would hardly believe how great their work is, they're so quiet about it. Do you know what a human nitrogen factory is like? Well, for one thing, it's the noisiest place in the world. Men, as do the bacteria, capture the nitrogen out of the air, but they do it by keeping up continual thunder and rain storms in big barrels. You will find one of these factories described in an article in St.[Pg 203] Nicholas, Volume 45, page 1137. But what a fuss these human factories make! Why, in growing-time, out in the clover field, where the loudest sound you hear is the drone of the bumblebee among the blossoms, the little bacteria people down among the roots are making nitrogen so much cheaper than the big noisy factories that it only costs the farmer about one-fifth as much as the storm-barrel nitrogen. And yet, of course, it often pays to buy the artificial nitrogen, too. There are many more striking things about the habits of roots than I have had room to tell about here, which you will find in such books as Elliot's "Romance of Plant Life," Coulter's "Plant Studies," Coulter's "First Book of Botany," Allen's "Story of the Plants," Chase's "Buds, Stems and Roots," Atkinson's "First Studies of Plant Life," Darwin's "Power of Movement in Plants," France's "Germs of Mind in Plants," Gray's "How Plants Behave," Carpenter's "Vegetable Physiology," Detmer's "Plant Physiology," and Parsons's "Plants and Their Children." </blockquote> <hr style="width: 65%;" />[Pg 204] <div class="figcenter"><div class="figborder"> <ANTIMG src="images/i216.jpg" alt="" /> THANKSGIVING DINNER OF THE DORMICE They don't sit at the dinner table like that, to be sure, but along in the Fall and up to nearly the time of our Thanksgiving dinners, the dormice eat unusually heavy meals and put fat on their little bones to help them through the long, cold, and barren months of winter. </div> </div> <hr style="width: 65%;" /> <div style="break-after:column;"></div>

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