Stereo Copyright, Underwood & UnderwoodLondon and New YorkRicefields in the Ceylon HillsThe buffaloes are puddling up the soil before the seed is planted.
Stereo Copyright, Underwood & UnderwoodLondon and New YorkRicefields in the Ceylon HillsThe buffaloes are puddling up the soil before the seed is planted.
Stereo Copyright, Underwood & UnderwoodLondon and New York
Ricefields in the Ceylon Hills
The buffaloes are puddling up the soil before the seed is planted.
Were these hillsides of Ararat or thereabouts, the first place where man sowed and reaped a harvest?
At any rate, in those flat, fertile, alluvial plains of the Euphrates, and also in Egypt, the first great cities arose.
But even in the later Stone Age, which may have been about 58,000B.C., some of these Caucasian plants seem to have been in cultivation in Switzerland. Probably every subsequent invasion, first that of races with bronze weapons, and then of others in the Iron Age, brought with it new cultivated plants.
The Oat seems to be an exception to the rule, for, so far as one can gather, it was not a native of Asia Minor.
The first harvest was, however, in all probability, a very casual and occasional kind of thing.
Mason (Origin of Inventions, page192) has described such a kind of cultivation which was in existence amongst the American Indians quite recently. "A company of Cocopa or Mohave or Pima women set forth to a rich and favoured spot on the side of a cañon or rocky steep. They are guarded by a sufficient number of men from capture or molestation. Each woman has a little bag of gourd seed, and when the company reach their destination she proceeds to plant the seeds one by one in a rich cranny or crevice where the roots may have opportunity to hold, the sun may shine in, and the vines with their fruit may swing down asfrom a trellis. The planters then go home and take no further notice of their vines until they return in the autumn to gather the gourds" (E. Palmer).
There is an interesting point about the cultivation of those early savage peoples who built up for themselves unhealthy but elaborate wooden dwellings in the Swiss lakes, in order to escape wild beasts and human beings who were even more dangerous and ferocious than they.
Weeds occurred in those cornfields, cultivated by stone implements, some 60,000 years ago.
The seed of an Italian weed had been introduced with their corn, and was discovered in Switzerland!
Weeds are an extremely interesting group. A proverb about the hardiness and multiplication of weeds can be discovered in almost every language. "Ill weeds grow apace,"Unkraut verbessert nicht, and so on. They are very common. In fact weeds, wayside, and freshwater plants, have by far the widest distribution of all. There are twenty-five species which can be found over at least half the entire land surface of the earth, and more than a hundred occupy a third of it.[123]
Moreover, many of our common weeds existed in Britain when the glaciers and ice melted away, and there were as yet no people able to cultivate the ground.
The Creeping Buttercup, Chickweed, Mint, Persicaria, Dock, and Sheep's Sorrel had already colonized the country, before the Great Ice Age came upon them, and at least fourteen weeds were here when the first corn-raising savages landed in Britain.[124]
At first sight it is difficult to understand where and how they lived. One discovers a very few, however, if onebotanizes very carefully along the seashore, or on river banks where landslips have occurred, and in other such places where bare ground exists which is not the result of cultivation.
There these weeds fulfil a very important and useful purpose. The "red smear" of a landslip is soon tinted green with Coltsfoot, Chickweed and the like, and the bare earth, which was useless and supported no green covering, is very soon made once more a part of the earth's fruitful field. In such places the weeds are soon overcome and suppressed by the regular woods, grass, or thicket of the district.
It is far otherwise in arable land, where man desires to keep the ground bare in order to give his own domestic plants the best part of the soil.
Let us look for a little at what actually happens in an ordinary cornfield. It is not merely one generation of weeds, but whole armies, that the farmer has to contend with.
When the young corn is growing up (1) the bright yellow Charlock grows much more rapidly, and the whole cornfield is golden with it. The Charlock grows to some eighteen inches high, flowers, and sets its seed before it is suppressed by the growth of the cornstalks, which, of course, may be three or four feet or more in height.
(2) Another series of weeds, such as Spurrey, are growing in the shelter of the tall stalks, and their flowers are ripened and their seed scattered long before the corn is cut. (3) Another series, such as Polygonums, etc., become ripe and are about the length of the corn, so that when it is cut and thrashed the seed of the Polygonum accompanies the grain and is probably sown with it. (4) Then there are such weeds as the False Oat grass, etc., which are taller than the Oat, and whose seeds are blown off and scattered all overthe field before the harvest. One would think that those exhausted the series, but far from it: the farmer cuts and carries the crop, and for two or three days the ground is almost bare, but if you revisit the field a week afterwards you can no longer see the ground. The cut-off yellow stalks of the corn are set off by a dark continuous green carpet of flourishing weeds. This last, (5) the "waiting division" of the weeds, remain quietly until the corn is removed and then get through their flowering and seeding before the field is ploughed up or covered by grass.
Now if one thinks for a little over the cunning and ingenuity of these proceedings, it is obvious that each single weed has somehow learnt how to develop exactly at the right time. Those especially which are intended (by themselves) to form part of the seed mixtures must flower exactly at the same time as the corn. As a matter of fact, most seed mixtures are often full of weeds. In a single pound of clover seed, no less than 14,400 foreign seeds, including those of forty-four different weeds, have been discovered.[125]
Others scattered on the ground will probably be buried and remain five to seven years below the surface, yet they are ready to come up flourishing as soon as they get a chance.
How has this been brought about? It is only since about 1780 to 1820 that our present system of farming has prevailed. In these 125 years, these weeds have found out exactly how to establish themselves.
The explanation is probably a very simple one. Every weed which did not bloom and seed exactly at the right time was killed and left no seed. This encouraged the others, who have gradually brought about the neat littlearrangements above described. A process of selection has been at work. Those that would not modify their arrangements to suit new methods of farming have been suppressed.
But it is in some of the cultivated plants themselves that one sees the most extraordinary results of selection.
The Wild Cabbage is still to be found on sea-cliffs on the south-western coast of England, and the Wild Turnip occasionally occurs in fields. There is nothing particularly interesting or attractive about either of them.
Yet from the one has been produced cabbage, cauliflower, seakale, brussels sprouts, broccoli, and kohlrabi; and the other has given the endless varieties of turnips. For the most part these extraordinary changes have been brought about in a perfectly straightforward way, by just choosing the biggest and finest sorts for seed.
Some of the feats performed by gardeners in this way are almost incredible. A United States seedsman evolved the idea of a perfect bean from his inner consciousness. It had a particular shape which he described to a noted grower of beans. Two years later his ideal bean was produced!
The growers of pineapples used to have a great deal of difficulty on account of the pineapple cuttings becoming unhealthy. Sometimes 63 per cent. were more or less diseased. Then certain growers began to carefully select disease-proof pineapples, and finally reduced the percentage of diseased cuttings to four per cent. Another French observer (M. Roujon) by continually selecting the smallest seeds, was able to obtain corn only eight inches high.
But by far the most interesting and important researches have been those dealing with roots and tubers. Several people have, in fact, done in a few years what it took primitive man centuries to accomplish.
Thus, in 1890, E. v. Proskowetz obtained some seeds of the wild Sea-beetroot which is found on the south coast of France. By very careful selection he was able in the year 1894 to get good beetroots quite like the ordinary cultivated ones. These were biennials (not annuals like the wild plant), and had a large percentage of sugar—16·99 per cent. This was by selection in good and fertile soil.[126]Vilmorin also obtained quite good carrots in the fourth generation by cultivating the wild form in rich and good soil, and selecting the best.
In fact there are in natural wild plants great differences between individuals, and when such plants are cultivated in good soil, where they have far more to eat than they require, the result is that they produce extraordinary and monstrous types.
These types are, however, more or less delicate, and are weak in constitution and easily killed. To prevent such variations those who wish to keep a race of seed pure are careful to keep it growing on poor land.
In 1596 the Hyacinth (Hyacinthus orientalis) was introduced from the Levant. In 1597 there were four varieties, and in 1629 eight kinds were known, but in 1768 two thousand forms of hyacinth were named and described.
Besides selection, the method of hybridizing or crossing is often used in order to obtain new or valuable strains. Generally both hybridizing and crossing are employed. This method has long been practised. Bradley, in 1717, writes as follows: "A curious person may by this knowledge produce much rare kinds of plants as have not yet been heard of"; and, in fact, peaches, potatoes, plums, strawberries, and savoys have all been greatly improved byhybridizing and selection.[127]By crossing certain kinds of corn, such as the Chinese Oat and the wild European Oat, varieties have been produced by Messrs. Garton which at the Highland and Agricultural Society's trials produced 84, 87, and 99 bushels per acre, as compared with 58 bushels yielded by the ordinary Scotch Oat.[128]With potatoes also astonishing results have been got.
Queensland Government PhotoSugar Cane in QueenslandThe cart is being loaded up to carry the canes to the factory, where it will be crushed by the latest and most perfect machinery.
Queensland Government PhotoSugar Cane in QueenslandThe cart is being loaded up to carry the canes to the factory, where it will be crushed by the latest and most perfect machinery.
Queensland Government Photo
Sugar Cane in Queensland
The cart is being loaded up to carry the canes to the factory, where it will be crushed by the latest and most perfect machinery.
One single potato was sold for £50 not very long ago.
The Potato, like the Indian corn, tobacco, and a few other plants, is an inhabitant of the New World. Of other cultivated plants the native country is not known. No one knows where, for instance, Sugar-cane was first cultivated, but it has nine Sanskrit names, one of which,khand, is, or has probably at one time been familiar to us as sugar-candy. It was well-known when the Institutes of Manu were written, but that may have been somewhere between 2000B.C.andA.D.20.
One of the Hindu Indian deities, Kámadeva, who corresponds to Cupid, the God of Love, carries a bow made of sugar-cane, with a string which is composed of bees.
"He bends the luscious cane and twists the stringWith bees: how sweet! but ah! how keen their sting,He with five flowerets tips the ruthless dartsWhich through five senses pierce enraptured hearts."
"He bends the luscious cane and twists the stringWith bees: how sweet! but ah! how keen their sting,He with five flowerets tips the ruthless dartsWhich through five senses pierce enraptured hearts."
"He bends the luscious cane and twists the stringWith bees: how sweet! but ah! how keen their sting,He with five flowerets tips the ruthless dartsWhich through five senses pierce enraptured hearts."
"He bends the luscious cane and twists the string
With bees: how sweet! but ah! how keen their sting,
He with five flowerets tips the ruthless darts
Which through five senses pierce enraptured hearts."
From India it seems to have been carried by Alexander the Great to Asia Minor, for it is mentioned by Herodotus. In the time of the Crusades it was discovered in Syria, and the Venetians learned something about it when the Crusaders returned to Europe. The Spaniards introduced the Sugar-cane to the Canary Islands in 1470. Then the Dutch tookit to Brazil, and when they were expelled from that country by the Portuguese they transferred their canes to the West Indian Islands. Our English islands, Barbados (1643) and Jamaica (1664), soon found the cultivation a very profitable undertaking.[129]
The variations in price of sugar became in process of time of a very serious nature. In the year 1329 it is said that in Scotland a pound of sugar was worth one ounce of standard silver. But from 1780 to 1800 the price fell to 9d. The East Indian sugar began to compete with that from the West Indies about this time, but this was very soon crushed out by imposing a duty of £37 per cwt.
The West Indies were then very flourishing, but even before this the fatal wordbeet-sugarhad already been heard. It was nothing at first but an interesting experiment by Professor Marcgraf in a German laboratory, who had extracted a little cane-sugar from beetroot in 1747. But in 1801 the beet was already in cultivation. Napoleon saw England's monopoly of the cane and judiciously encouraged the beet. The result of his far-seeing policy only became manifest a few years ago, for then the West Indian Islands, which we conquered and guarded against Napoleon at such fearful expense of blood and treasure, were almost worthless; Continental beet-sugar had ruined our colonial planters and our home refineries. It is in fact a most curious and interesting example of how a little judicious encouragement by a wise and far-seeing Government may destroy the profits of victory in a long, glorious, but yet ruinous war.
Meaning of Plant Life—Captive and domesticated germs—Solomon's observations denied by Buffon but confirmed by recent writers—Ants as keepers and germinators of corn—Ant fields—Ants growing mushrooms—Leaf-cutting ants—Plants which are guarded by insects—The African bush—Ants boarded by Acacias and by Imbauba trees—Ants kept in China and Italy—Cockchaferv.ant—Scale insects—A fungus which catches worms.
THE world of plants supports all animal life, from the mite to the elephant. There are most intricate relations between one form of life and another. Thus a Rose tree attacked by an aphis or green-fly may be succoured by the slim ichneumon, or other thin-waisted fly, which lays its egg in that of the aphis. Another insect, say a spider, catches the ichneumon. A starling may eat the spider, and be itself eaten by an owl.
So that ichneumon and starling are friends to the Rose, whilst the other insect, the spider, and the owl are enemies. Yet both the starling and the spider are probably, almost certainly on the whole, friends of the Rose, although they are unfriendly in this special case.
With all other similar series or changes the final term is either a bird or animal of prey or mankind.
Until we introduce the idea of man as the culminating point of the series, the whole of it seems to be without any special meaning or advantage.
But when we think of how man utilizes the work of plants and animals, then the whole scheme becomes intelligible and complete; it is like a well-rounded story with a worthy and adequate end.
Moreover, what man has done so far is only an instalment of what he will probably succeed in doing. All who have brought up caterpillars or bees know that their greatest difficulty arises from certain minute insects or fungus enemies. We already know enough about these latter to fight them with some chance of success, but there are hundreds of other spores and germs floating in the atmosphere, and coming to rest on animals, on clothing, or on the leaves or petals of plants. These germs are now just as wild as, and infinitely more dangerous than the furious aurochs, the disdainful wild asses, or the ferocious wolves that our forefathers succeeded in domesticating.
Those bacteria, or germs, for instance, which are only one-thousandth of a millimetre long, are only visible by the help of a microscope. A row of three hundred thousand of them would be required to make an inch in length! Yet one of these germs can be mature and divide into two new germs in twenty minutes. In forty minutes there would be four, in an hour eight, and so on. The number after twenty-four hours is almost incredible.
These little germs stick to our clothes, fingers, lips, money, newspapers, and anything that is often handled. They hover in the air we breathe, permeate the food we eat, and inhabit water, and especially milk, in enormous numbers. Some of them are deadly. One might easily decimate a whole population, as indeed happened in the South Sea Islands when smallpox was introduced. Others are harmless and even necessary.
But to-day if you go into a bacteriological laboratory you will find hundreds and thousands of little glass tubes all neatly labelled and stoppered with cotton wool. If you read those labels you will see that the bacteria of all sorts of horrible and loathsome diseases have been captured and imprisoned. There is the deadly anthrax bacillus peacefully discolouring gelatine; in another, possibly the germs of hydrophobia may be undergoing a process of taming or treatment.
Each of these colonies of germs is under perfect control, and in many of them their natural wickedness has been so much alleviated that they are now useful aids to the doctor, who gives his patient a mild dose of the disease in order to accustom his system to resist accidental infection by the original type.
Yet what has been done already is only an earnest of what will no doubt be accomplished. Every farmer and ploughboy will in time sow his own bacteria; every dairymaid will make all sorts of cheese, from Camembert, Rochfort, to Gorgonzola, by sowing the right kind of germ upon it.
Man will no doubt cultivate the whole earth in the way that he now cultivates Europe and Great Britain, and will obtain mastery not only over his domesticated plants and animals, but over fungi, bacteria, and insects also.
Even if man had never risen above the state of the Banderlog of Mr. Kipling, there are other animals which cultivate and even combine together for warfare and conquest. In some respects they are better disciplined even than man himself, and they can defy all sorts of mankind except civilized man.
Possibly if man had not arisen on the scene, these insectsmight have developed some sort of civilization like that imagined by Mr. Wells in his story of the moon. We are only concerned with the relations of these ants to plants. Those who are interested in their conquests and civilization must consult the excellent account by Mr. Selous in hisRomance of the Insect World.
The most interesting points about them are as follows. They gather a harvest and store it up for the winter. This habit of the ant was well known to the ancients, and is mentioned by Solomon. At the time of the French Encyclopædists, when the fashion of the times was all for destruction and disbelief, the fact that ants do so was ridiculed and flatly contradicted, and especially by the great naturalist Buffon. They pointed out that ants hibernated during the cold weather, and therefore required no food for the winter, so that Solomon's story was absolutely ridiculous.
For nearly a hundred years people forgot that Palestine and those other countries where the habits of ants had been reverently observed possessed a climate much too warm and mild to make the ants hibernate.
After careful study it has been discovered that the ants thoroughly understand the first stages of brewing!
The corn which they gather is not eaten by them in its hard winter condition. When taken into the winter nest of the ants this corn would very soon germinate and grow into a plant, but the ants manage to prevent this by some method which is not yet understood. If such a nest is left alone by the ants, the corn immediately begins to grow, but it is not allowed to do so till it is required for food. Should the store of corn get damp by heavy rain, or mould appear upon it, then the careful ants bring up their store into the sunlight and dry it there.
When it is required for food germination is permitted, but is soon stopped: the ants nibble off the growing rootlet of the seed. Then when the grain absorbs water and begins to change its starch into sugar, the ants suck in the sugar and reap the reward of all this labour and skill.
In the conduct of this germination of the grain they are, of course, far in advance of all the savage races of mankind.
There are certain South American species which go at least one step farther. They have their own fields—spaces three or four feet in diameter—which are entirely occupied by one single grass, the so-called Ant-rice (Aristida stricta). Dr. Lincecum states that the ants "work" these plantations very carefully, removing every weed or other plant that comes up, and sowing every year the new seed at the proper season.[130]
These facts are sufficiently strange and startling, but there are even, apparently, species still more intelligent, who not only sow and reap, but actually prepare a soil and reap a crop of mushrooms, or at least, if not of mushrooms, of fungi. These wonderful little insects gather leaves and cut them into fragments of an appropriate size; they are then collected together so as to form a bed, and the fungus is introduced to this. The fungus is kept at a certain stage of growth by very careful treatment; the fruit-bearing ends are nibbled off, so that the young shoots come up indefinitely. The ants feed upon these fungus shoots, and get a crop indefinitely prolonged.
This is, of course, a system of agriculture far beyond that employed by any tribe of savages. Only man in a relatively advanced stage of agriculture grows mushrooms for himself.These facts, startling as they may seem, are apparently quite well authenticated and have not been seriously questioned.
There are a great number of leaf-cutting ants who are, indeed, amongst the most dangerous of the many insect pests in South America and elsewhere. Wallace (Revue Scientifique, 179, p. 29), in speaking of the Saauba or leaf-cutters, describes how he placed a large heavy branch across the route of one of their columns.
The long line of laden ants was checked, and the greatest confusion set in at the head of the column. Each ant, for several feet down the column, then laid down its leaf, and all set to work to tunnel under the obstacle. This was managed in about half an hour's time, and the column then proceeded on its way.
Amongst other interesting and curious facts connected with these extraordinary insects is that some kinds are actually kept up by certain plants as a sort of standing army or police.
There are no less than 3030 species of plant which keep these standing armies of ferocious ants, or if they do not keep them, at any rate lay themselves out to attract them. The kinds which are attracted live upon sugar, and are strong, active, and extremely good fighters. When travelling through the bush in Africa, it is not unusual in some places to touch inadvertently one of these protected trees. In a moment one's hand and arm are covered by ants whose heads are dug deep down into the skin, biting with all their strength.
It is of course impossible to describe all the plants which protect themselves against injurious insects and even large animals in this way, but two of them must be mentioned.
There are certain Acacias which are particularly interesting. Like most of this order, they have large hollowspines instead of stipules at the base of the leaf. It is inside these spines that the troops of the police-insects live. These Acacias (Oxhorn Acacia, as well asA. sphærocephalaandA. spadicigera) also producesugar, which is secreted by peculiar gland-like organs on the stalks of the leaves, and evenalbuminoids, for at the tips of the leaflets there are peculiar little bodies which contain albuminous matter.
The Imbauba tree (Cecropia spp.) also possesses a standing army of these ants. It puts them up in the hollow pith in the centre of the tree, which is divided into large roomy spaces and makes a convenient nest. There is a minute opening by which they run in and out. On one occasion a naturalist found that the ants had been benumbed by a period of very cold weather, and in consequence had neglected their duty, and the trees had been stripped of their leaves by leaf-cutting kinds.[131]
These last mentioned, the leaf-cutting ants, are especially dreaded by owners of plantations. Foreign or introduced plants are not specially guarded against their ravages by special secretions, as is the case with the native flora, so that the coffee and cocoa plantations are often severely injured. In some places man has copied those Acacias and Imbaubas, for in the orange plantations of the province of Canton, in China, ants' nests are collected and placed on the trees. Moreover, the different trees are connected together by bamboos, so that the ants can easily pass, as on a bridge, from one tree to another.
Near Mantua, in Italy, the same system seems to be adopted, and ants' nests are carefully placed near the fruit trees. Their use can be quite well understood, for Forel, in his work on the Ants of Switzerland, estimates thatone ants'nest will requirea supply of 100,000 insects a day during the season.
It is quite common to find ants crawling about on the outside of the large heads of the Garden Centaury and a few other Composites. If one looks carefully, one finds that there are streaks of honey to be seen coming from the scales. The honey is not produced in the flowers, and seems at first sight to be of no use at all so far as the plant is concerned, but that is very far from being the case. Here comes a cockchafer or other destructive beetle, intent on absolutely devouring and destroying the young flowers. At once the pugnacity and wrath of the ants are aroused. They take up a menacing and ferocious attitude, and the cockchafer passes to some other plant.[132]
Such honey-glands found on the leaves and not connected in any way with the flowers, are more common than one would think. Even the common Bracken produces curious honey-secreting hairs when it is in a young condition. These attract ants which drive away caterpillars and other dangerous insect foes.
Many very dangerous insects are too small for birds, and can only be dealt with effectually by insects or fungi. Of these perhaps the most dangerous are the "scale" insects. The best-known one is very like a minute mussel shell. It is about one-quarter to one-third of an inch long, and can be sometimes found in quantities on apples; they are generally collected round the stalk. The mother insect has this scaly back, and lies down and dies on the top of her eggs, so that her scaly corpse forms a roof and a shield for her young ones. Like all pests of this sort, these creatures increase very rapidly.
A certain scale insect was doing an immense amount of harm in the orange plantations of Fiji, but it was destroyed by the introduction of lady-birds, and of a certain parasitic fly. It is said that these insects destroyed the "scale" in six months!
Experiments have also been tried with fungi. There are certain fungi which attack the bodies of living insects. So far, however, it cannot be said that the results have been at all satisfactory, for the propagation and infection of the living insects by fungus spores is not at all easy. There is also a certain feeling of doubt as to what may happen. Those fungi, and particularly bacteria, might set up dangerous epidemics.
Decaying meal contains hundreds of certain very curious worms calledNematodes. They are short, about one-twenty-fifth of an inch in length, and are smooth and very like minute eels. These creatures are very active, wriggling or swaying to and fro in a characteristic manner. Now in decaying meal there is a peculiar fungus. Like most fungi, it consists of very minute transparent threads which contain living matter or protoplasm. This particular fungus has branches, but also forms curious loops or belts. When one of these eel-worms is swaying about in the meal, it may quite well happen that its tail slips into one of these loops. If that happens, the fate of the worm is sealed, for the loop is elastic, and the more it wriggles the farther it slips in and the stronger it is held. The fungus then begins to grow, and forms a tube which growsinto the wormand kills it. All the material in the worm's body goes to nourish the fungus. This extraordinary fungus has been described and figured by Professor Zopf, but seems to be a very unusual and rare form.
The Phylloxera—French sport—Life history of the Phylloxera—Cockchafer grubs—Wireworm—The misunderstood crows—Dangerous sucklings of greenflies—"Sweat of heaven" and "Saliva of the stars"—A parasite of a parasite of a parasite—Buds—The apple-blossom weevil—Apple-sucker—The codlin moth and the ripening apple—The pear midge—A careless naturalist and his present of rare eggs—Leaf-miners—Birds without a stain upon their characters—Birds and man—Moats—Dust and mites—The homes of the mites—Buds, insect eggs, and parent birds flourishing together.
THE difficulty in describing the Romance of Plant Life does not arise from a want of romance, but the sieges, battles, and alarms are so difficult to see, and the enemies are so tiny, that the terrific contests continually going on escape our notice altogether.
When one does look carefully and closely at the life of a plant, one sometimes wonders how it manages to exist at all in the midst of so many and great dangers.
There are great swarms of insects which devour or burrow into it, or suck its life-juices. These are infinitely more dangerous than the relatively clumsy, heavy-footed, grazing animal.
Every part of a plant has its own special insect foe, and it is really difficult to understand how it can possibly escape.
Perhaps the "Achilles' heel" is the root, for, underground, plants get no help from the watchful and ever-present armyof birds, who are, as we shall see, the natural police of the world.
The Phylloxera, for instance, which ruined the old and valuable vineyards in France, is a terrible little acarid, or mite, which attacks the roots. Too small to see, and impossible to kill without killing the plant, it laid waste the fertile hills and valleys of all South and Central France, causing millions of pounds damage. One reason for this destruction sprang from the universal sporting instinct innate in every Frenchman. Everybody goes out with his gun to destroy any lark, sparrow, or titmouse that is idiotic enough to remain in the country. Only birds can deal efficiently with insect pests. Take this horrible little Phylloxera, for instance; a single female in her life of forty-five days will lay about two hundred eggs. Each egg becomes a little grub, which after a few moments of uncertainty and agitation settles itself, and begins to suck steadily at any unoccupied part of the vine root. After ten to twelve days' life it will be laying eggs as rapidly as its mother. Thus in an ordinary summer the number of young ones produced from a single female becomes quite incalculable.
These pests are natives of America. Imported on American roots about 1868, they had in thirteen years practically ruined the vineyards in France, Spain, Portugal, Italy, and Germany.
All sorts of remedies were tried—saturation of the ground by poisons, flooding the vineyards to drown them, artificial cultivation of their insect and plant enemies, and many others.
The correct and satisfactory method has been at last discovered. American vines of sorts which are able to resist these Yankee mites have been imported, and the valuable French vines have been grafted on to them.
Another very dangerous root-enemy, which is common in this country, is the Cockchafer grub or Whitegrub. (But it is not nearly so bad as in France, where in the summer of 1889, a single farmer collected 2000 lb. of Cockchafers.) The grub (each female lays seventy eggs) burrows into the earth, and for no less than three summers remains below ground devouring indiscriminately the roots of everything he can discover. Underground, the mole is almost his only enemy, but the rooks, starlings, and gulls, which follow the plough, are watching for him. The Wireworm, Clickbeetle, or Skipjack, is also an underground demon which lives for three years, and gnaws and worries at plant roots for the whole of that time. It, however, shows itself above the surface.
A gentleman who had passed his whole life in the country complained, in my presence, of the damage done by rooks. He had had six thousand of them shot that summer, and remarked that he had seen with his own eyes one of them pulling out a young cabbage plant by the root. Of course it was quite unnecessary to point out that the poor bird was merely trying to get at the wireworms and devour them!
For some time I used to look out for great attacks of wireworm in turnip-fields: when one was recorded, I never failed to find that the crows had been ruthlessly shot down a season or two before.
All these, and many other insects, attack the roots, which would be, one would suppose, quite well protected in the depths of the earth. Therefore we find roots producing all sorts of poisonous substances, tannins, and even strong-smelling bodies, which keep off these pests.
It is perhaps the sucking battalions of the insect army which do the most harm. In themselves they are weak,stupid, and scarcely move from their birthplace. They live out their life wherever their long, lancet-like proboscis needles have pierced the plant's skin, but it is their power of multiplication that makes them really formidable.
Huxley calculated that if all the offspring of one "green-fly" lived, and if their broods also lived for ten generations, then the tenth brood of that original green-fly would contain more animal matter than the entire population of China. Green-fly would, as a matter of fact, go on increasing at this rate, were it not for the enormous number of enemies that prey upon them. A mathematical friend of Mr. Buckton calculated that in 300 days the produce of a single green-fly might be 21015, that is 210 multiplied by 210, and then again by 210 up to 15 times!
In summer time one may often notice, especially on sycamores and lime trees, a peculiar shining, sticky, honey-like substance which covers the leaves. It is often so abundant as to drip like a rain of honey from the upper branches.
This "honey-dew" was a puzzle which greatly intrigued learned minds in the ancient world. Pliny speaks of it as the "sweat of heaven" or "saliva of the stars."
In reality, however, it is nothing but the excretions of hundreds of millions of these green-fly or aphides, which will be found established on the under side of the leaves, where, moored by their little anchoring talons and with their proboscis inserted in the fresh green leaf, they are sucking hard and steadily at the sugary juice. In twenty-four hours it was observed that a single individual gave forth forty-eight minute drops of honey.
Bees are very often tempted to collect this honey so abundantly produced, but this turns their own honey black, and may even make it poisonous.
Plants try to protect themselves against these pests chiefly by means of sticky or long hairs, by a thick skin, or by unpleasant tasting or smelling substances. But it is to insects such as lady-birds and others which devour the green-fly that they owe a deep debt of gratitude. In particular, there are certain parasitic insects which lay their eggs in their bodies. Not only so, but it is known that the eggs of some other insects are laidin the egg of the green-fly, and in one instance it has been found that yet another insect laid its egg in the egg of the parasite!
Some of the most interesting objects in nature are the buds in which, all neatly packed and stowed away, the young leaves and flowers remain awaiting the warm breath of spring. They are most interesting to examine: one finds series after series of overlapping scales which cover one another in the most ingenious way. No two are exactly alike, but each seems to have been moulded exactly to the proper shape. There is no waste anywhere, no useless expenditure of material. Very often turpentine or resin or a sticky gum seals up the joining of the scales. Every possible precaution seems to have been taken by nature. Neither rain nor snow can enter a winter bud. Neither can the cold of winter penetrate to the inside where the baby leaves and flower petals are cosily and tightly coiled up. But observe in the very earliest warm days of spring an extraordinary little insect, which has wakened up after its own winter sleep in the moss or lichen covering the rough and crannied bark of an old apple tree. This is the Apple-blossom Weevil, a beetle only about quarter of an inch in length, but with a curious snout or proboscis half the length of its body. This creature proceeds to the bud, and fixing its legs firmly, proceeds to bore a hole through the scales into the middle ofthe bud. She then places an egg inside, and goes on to put an egg in each of fourteen to forty-nine other buds. This takes a fortnight, and then she dies, probably satisfied that her duty is fully performed. A little footless, cream-white maggot develops in the apple-bud, which latter becomes rusty-coloured and dies away.
Another pest is the Apple-sucker, which lays her eggs in September on the fine hairs which cover the shoots. As soon as the weather becomes mild and warm, little grubs come out of these eggs; they are very small, and their bodies are almost flat. These tiny flat grubs, as soon as they are born, hurry off to the nearest buds and slip between their scales. They remain sucking the rich juices of the apple blossom until May or June, when they become perfect insects, and fly away so fat and well-nourished that they can live until September without feeding.
But those are by no means the only dangers. It is not till the apple blossom, which has escaped all those perils, opens in the spring time, after its petals have unfolded in the warm air and the young apple is already half formed, that the Codlin Moth begins to attack them. This tiny little moth is then extremely busy. She lays about fifty eggs, but only one on each young apple. It is put in the one weak spot of the apple, just at the top, in the base of the withered flower. The grub tunnels down to the core and feeds upon the seeds, which are entirely destroyed. When it has grown sufficiently, it drives another tunnel straight outwards to the skin. If the apple is still on the tree, the caterpillar lets itself down on a long silken thread and hurries off to hide in any convenient crack or crevice of the bark, or if the apple is already stored away, it conceals itself in the walls or in the flooring of the loft. The moths comeout at the end of next May, just when the blossoms are getting ready for them. These codlin-moth apples cannot fail to have been noticed by the reader, as the tunnels in the ripe apple are most conspicuous. The gradual fattening of the caterpillar can also be traced, for its first tunnel down to the seeds is quite narrow, while the way out gets wider and wider as the creature became stouter and fatter whilst eating its way through the flesh.
The Pear Midge attacks at the same place, but the mother insect has a long egg-laying tube, and puts from fifteen to thirty eggs into the opening pear blossom. The pears go on growing, but of course are quite spoilt by the maggots within. These latter have a curious springing or jumping habit, and when they reach the soil bury themselves an inch or two below the surface.
So that all the care and neatness with which the young flowers and buds are packed up goes for nothing, and these insect pests get all the benefits of the apple and pear!
Besides these, there are hundreds of sorts of caterpillars which devour the leaves bodily. Cabbage-white butterflies, magpie-moths, gipsy-moths, diamondback-moths, and others, lay their eggs in hundreds. Many lay 300 eggs each.
In the United States, somebody had sent an entomologist a present of some eggs of one of these moths. They were placed on a paper near a window which happened to be open; the entomologist went out, and the paper must have blown across the street into a garden on the other side. At any rate, two or three years afterwards it was found that some trees were badly attacked by this moth. Nobody thought much about this, though of course it was interesting to find a new moth. But the pest became a very serious one. In consequence of the stimulating air of the United States themoth multiplied with the most extraordinary rapidity, and it is said that about 300,000 dollars was spent in one year in the attempt to stamp it out.
All this happened because an entomologist forgot to lock up his eggs when he went away for half an hour!
These caterpillars and the locusts devour the leaves bodily, but there are others which live inside them. These so-called "leaf-miner" caterpillars make white irregularly-winding tunnels between the upper and the lower skin of the leaf. The tunnel increases or widens because the caterpillar itself grows fatter as it eats its tunnel. They can be seen on a great many leaves, and can be at once recognized by this peculiarity.
Plants cannot run away from their enemies like animals, and it would seem at first sight that their case was very hopeless. But it is not so, for there is a vast, active, keen-eyed, and eager army of helpers always ready for eggs and caterpillars.
It is birds that are of the greatest importance. A titmouse will eat 200,000 insects in a season. A starling has been seen to fetch food for its young ones from a grass paddock 100 yards away no less than eighteen times in a quarter of an hour. All the following are excellent birds, and without a stain upon their characters: the plover, partridge, robin, wagtail, starling. Crows and wood-pigeons are under suspicion, for though the latter do good in devouring the seeds of weeds, and the former in destroying wireworms, both are fond of corn and take large quantities of it.
Thrushes, mavises, and blackbirds are amongst the most persevering and useful of our friends, but they are certainly fond of fruit. Yet the good which they do is very muchmore than any possible harm which an injudicious indulgence in the juicy fruits of summer might bring about.
The sparrow cannot be given a character. Indeed, he is objectionable in every way, for he not only does no good himself, but he devours corn and drives away starlings and other valuable and interesting helpers.
But it is very difficult to say what will happen if man interferes with the regular working of Nature. The starling has been a pest in Australia, though here it does nothing but good work. We are still grossly ignorant of many simple but very important facts. Even when we do know something, as for instance, that the peewit's or plover's whole life is occupied in clearing the ground of wireworm, daddy-long-legs grub, insects' eggs, and the like, that does not help the bird in the least. Plovers' eggs are regularly sold in enormous quantities. Every farm-labourer collects them, and the farmer never dreams of interfering.
Man shoots down owls, kestrels, hawks, who prey upon mice, voles, and sparrows. Then, when some farmers are half ruined, he has Royal Commissions to find out why the voles have increased so much.
There are one or two peculiar contrivances found in plants which are intended to keep off insects, and which may be noticed here.
Thus, the importance of a moat (which almost always formed part of the defence of a medieval castle) had been already found out by one or two plants.
In a particular kind of Teazle and in a large Sunflower-like Composite (Silphium laciniatum) every pair of two opposite leaves run together, so that a little cup-like hollow is formed surrounding the stem, in which water collects. Insects climbing up the stem and trying to get at the headsof flowers fall in and get drowned in this water; their bodies may be seen floating about in it, and probably when these decay, their decay-products are of some use to the plant.
This curious contrivance is only a development of a very common arrangement. In most leaves you will find that rainwater is intended to run in a particular direction. There are little grooves and canals down which it is supposed to go, and dry, thirsty hairs may be found so arranged as to intercept part of it. Thus in summer the plants are not confined entirely to the water from the ground, but are also refreshed by the rain from above.
But if you look closely along these little channels, and especially at the base of the leaf where they join the stem, you will find that dust particles washed down by the rain collect and form little streaks and patches. The air is full of all sorts of dust particles which are made up of every conceivable substance. Many of these minute grains of dust will be dissolved in the water, and help to supply the plant with food. Nor is that all, for if you take a hand-lens and examine these dust particles very closely, you will very probably find small animalcula moving about. They are not pretty; in fact they are quite horrible to look at. These are tiny mites which live in these places. Their office is probably to eat up everything eatable (including eggs of insects and spores of fungi), and their excreta as well as their own bodies will probably be dissolved in the water and go to help the plants.
The most certain place to find them is on the leaves of the lime and other trees in August. On the under side of the leaf little bushes of hairs can be found just where the veins fork. It is necessary to take a pin and stir up these hairs to frighten them out, but when this has been done, thelens will show the disgusting-looking little creatures running hurriedly away. They are no doubt exceedingly annoyed at being disturbed in the midst of their sleep, for they come out and forage for anything eatable at night, retiring for the day into these hairy grottos. The structure of these grottos is very complicated. They are often like little caves with a narrow entrance, and the sleeping chamber is quite within the leaf.
A great many trees have these curious mite homes. The insects are generally the colour of the hairs, and are not easy to distinguish.
All those insects mentioned here have so arranged their life histories that they come into existence exactly at the proper season. The warmth of the sun, which opens the apple buds ever so slightly, stirs also the egg of the mite, the egg of the beetle, or the hibernating weevil, so that all these insect populations come into full active life just when they can do the most damage.
But one must not stop there; the bird population is also ready, and is building its nests and feeding its young, just so soon as the insect swarms are at their thickest and most dangerous stage.
Man walks clumsily through this intricate tangle of living plants and animals: he sets his big foot on a hedgehog (good for the insects), or on a mole (so much the better for wireworm), collects plovers' eggs (to the great help of every insect), shoots an owl (to the delight of voles and mice) or a whole brood of partridges, and in other ways makes a—— we had better say, shows that he is not so clever as he supposes himself to be.
Effects of opium—The poppy-plant and its latex—Work of the opium-gatherer—Where the opium poppy is grown—Haschisch of the Count of Monte Cristo—Heckling, scotching, and retting—Hempseed and bhang—Users of haschisch—Use of india-rubber—Why plants produce rubber—With the Indians in Nicaragua—The Congo Free State—Scarcity of rubber—Columbus and Torquemada—Macintosh—Gutta-percha.
SUPPOSING that in China or Japan you meet a native who shows the following symptoms:—
(1) Eyes hollow and surrounded by a bluish margin; (2) pupils much dilated; (3) with a stupid appearance; (4) with an emaciated body; (5) of unsteady and staggering walk; (6) with a dreamy disposition;—then, you may be sure that he is an opium-smoker. In some of the Chinese provinces every man smokes ·03 to ·07 ounce of opium daily, but those who indulge to excess consume ·3 or even ·6 ounce. It is an excellent medicine when employed in a lawful and justifiable manner, for it calms the spirits and makes one sleep. But its use isalwaysdangerous, even when employed in very small quantity, as in laudanum and morphia.
In the Fen country in England there used to be a very large sale of laudanum pills which keep off asthma and rheumatism, but even there it is a dangerous remedy, for it is only too easy to fall under the control of this drug either byinjection of morphia, or by eating or smoking laudanum or morphia. De Quincey'sConfessions of an Opium-eaterand Kipling'sGate of the Hundred Sorrowsgive a lurid picture of the ruin of body and soul brought about by opium.
It is produced from the heads of the Opium Poppy (Papaver somniferum). Any poppy (or indeed any plant of the Poppy order) when scratched or wounded exudes a thick white or orange milky fluid. This is called "latex" (or milk); it is always more or less poisonous, and generally contains some sort of resinous matter. Thus when the plant is scratched or pierced, a drop of this milky latex comes out and at once hardens over the wound. Of course the plant is much benefited by this, for any destructive insect, unless it is a confirmed opium-eater, will be poisoned or killed; then also, if wounds are caused by wind, heavy rain, or animals passing, the scar is at once healed over and covered by the hardened opium, so that no dangerous fungus spores can get in to attack the plant. There is a mildew fungus and also a smut fungus (Entyloma) which attack the poppy, but both these enter by the stomata and live between the cells of the plant.
The general appearance of the Opium Poppy is quite familiar; its upright stems, large, clasping, bluish-green leaves and conspicuous flowers may be seen in many gardens. It is rather interesting, and in many ways; when young, the buds droop or hang down, and are entirely enclosed in two large green, hairy sepals. These last are soon thrown off, and then the flowers open out and display the petals with their rich black spots, and the crowded mass of stamens which surround the central greenish head. In bud these petals are "cramb'd up within the empalement by hundredsof little wrinkles or puckers as if three or four fine cambrick handkerchifs [sic] were thrust into one's pocket," as an old writer describes it (Grew).
Bees, and especially bumbles, are extremely fond of it, and even seem to be, in a way, opium-eaters, for they get quite exalted, almost intoxicated, and above their ordinary laborious selves. They scurry round and round the flower under the stamens or hover excitedly above it.
It is at this stage that the opium-gatherer begins his work; he goes round the beds and collects the petals of the poppy to use later on (see p.304). The poppy-heads are then half grown and bluish-green, but they soon begin to turn yellow and ripen. When ripe they are most interesting to examine. There is a large platform covered by a radiating star-like ornament, which is the stigma. Underneath this is a circle of little holes just below the crown, but above the head. Each small hole has a flap. Now if you gather a ripe poppy-head on a fine dry day all these holes are open, and if you hold it upright and swing it vigorously from side to side the tiny seeds come flying out of the holes and will be thrown to a considerable distance. The stalk is supposed to swing in a high wind, and the seeds are really slung or thrown out of the holes. But if, when you come home, you put your poppy-head in water, or look at the plants in the garden on a very wet day, you will find that every hole closes or is shut up, because the small door mentioned above expands so as to close the opening.
The seeds are only sent out on a fine dry day; but they travel well. It was observed in America that certain poppies had been introduced as weeds at a certain place; in fifteen years they were found twenty-five miles farther on, so that they were colonizing the country at the rate of three-fifths ofa mile per annum.[133]The seeds themselves are very light and are of some value; they may be eaten like caraway-seed, as comfits, or crushed to supply an oil for lamps, or used as medicine. It is said that the value of the seed raised in France was in one year £170,000. The heads themselves are also valuable (they are worth 35s. per thousand), and even the dried stalks and leaves, for they may be used as fodder.
But the real reason why the plant is cultivated in so many parts of the earth is the great value of the opium obtained from it. This is gathered in the following curious way. As soon as the dew has dried off the plant, the cultivator goes round the beds and scratches every poppy-head with a tool made up of three knives tied together. That is the time recommended by Theophrastus, and it is apparently still the usual time to choose. In the late afternoon, from four to seven, he comes round again and scrapes off the congealed milk, which is then worked up into cakes and taken to the factory.
It is prepared by being kneaded, dried, and rubbed until it is of a pale golden colour.[134]Finally, it is enclosed in a mass of poppy petals, sometimes mixed with the fruits of a kind of dock, and is then ready for export.
It is cultivated in a great many parts of the world—Turkey, Syria, Persia, France, China, the United States, Germany, Queensland, but especially in British India, where the immense plains at Malwa used to furnish opium worth about sixty million rupees annually (after deducting all expenses). This was mostly exported to China, and amounted to a tax of about threepence per head on every Chinaman; it was also sufficient to defray aboutone-sixteenth part of the expenses of our Indian Empire. The story of how Great Britain forced China to take our opium is not a creditable one nor agreeable to read. The plant was known in ancient Egypt, Persia, and Rome, and was used in China for at least two hundred years before our times.