On this primitive principle, possession of a thunderbolt gives you some sort of hold, as it were, over the thunder-god himself in person. If you keep a thunderbolt in your house it will never be struck by lightning. In Shetland, stone axes are religiously preserved in every cottage as a cheap and simple substitute for lightning-rods. In Cornwall, the stone hatchets and arrowheads not only guard the house from thunder, but also act as magical barometers, changing colour with the changes of the weather, as if in sympathy with the temper of the thunder-god. In Germany, the house where a thunderbolt is kept is safe from the storm; and the bolt itself begins to sweat on the approach of lightning-clouds. Nay, so potent is the protection afforded by a thunderbolt that where the lightning has once struck it never strikes again; the bolt already buried in the soil seems to preserve the surrounding place from the anger of the deity. Old and pagan in their nature as are these beliefs, they yet survive so thoroughly into Christian times that I have seen a stone hatchet built into the steeple of a church to protect it from lightning. Indeed, steeples have always of course attracted the electric discharge to a singular degree by their height and tapering form, especially before the introduction of lighting-rods; and it was a sore trial of faith to mediaeval reasoners to understand why heaven should hurl its angry darts so often against the towers of its very own churches. In the Abruzzi the flint axe has actually been Christianised into St. Paul's arrows—saetti de San Paolo. Families hand down the miraculous stones from father to son as a precious legacy; and mothers hang them on their children's necks side by side with medals of saints and madonnas, which themselves are hardly so highly prized as the stones that fall from heaven.
Another and very different form of thunderbolt is the belemnite, a common English fossil often preserved in houses in the west country with the same superstitious reverence as the neolithic hatchets. The very form of the belemnite at once suggests the notion of a dart or lance-head, which has gained for it its scientific name. At the present day, when all our girls go to Girton and enter for the classical tripos, I need hardly translate the word belemnite 'for the benefit of the ladies,' as people used to do in the dark and unemancipated eighteenth century; but as our boys have left off learning Greek just as their sisters are beginning to act the 'Antigone' at private theatricals, I may perhaps be pardoned if I explain, 'for the benefit of the gentlemen,' that the word is practically equivalent to javelin-fossil. The belemnites are the internal shells of a sort of cuttle-fish which swam about in enormous numbers in the seas whose sediment forms our modern lias, oolite, and gault. A great many different species are known and have acquired charming names in very doubtful Attic at the hands of profoundly learned geological investigators, but almost all are equally good representatives of the mythical thunderbolt. The finest specimens are long, thick, cylindrical, and gradually tapering, with a hole at one end as if on purpose to receive the shaft. Sometimes they have petrified into iron pyrites or copper compounds, shining like gold, and then they make very noble thunderbolts indeed, heavy as lead, and capable of doing profound mischief if properly directed. At other times they have crystallised in transparent spar, and then they form very beautiful objects, as smooth and polished as the best lapidary could possibly make them. Belemnites are generally found in immense numbers together, especially in the marlstone quarries of the Midlands, and in the lias cliffs of Dorsetshire. Yet the quarrymen who find them never seem to have their faith shaken in the least by the enormous quantities of thunderbolts that would appear to have struck a single spot with such extraordinary frequency This little fact also tells rather hardly against the theory that the lightning never falls twice upon the same place.
Only the largest and heaviest belemnites are known as thunder stones; the smaller ones are more commonly described as agate pencils. In Shakespeare's country their connection with thunder is well known, so that in all probability a belemnite is the original of the beautiful lines in 'Cymbeline':—
Fear no more the lightning flash, Nor the all-dreaded thunder stone,
where the distinction between the lightning and the thunderbolt is particularly well indicated. In every part of Europe belemnites and stone hatchets are alike regarded as thunderbolts; so that we have the curious result that people confuse under a single name a natural fossil of immense antiquity and a human product of comparatively recent but still prehistoric date. Indeed, I have had two thunderbolts shown me at once, one of which was a large belemnite, and the other a modern Indian tomahawk. Curiously enough, English sailors still call the nearest surviving relatives of the belemnites, the squids or calamaries of the Atlantic, by the appropriate name of sea-arrows.
Many other natural or artificial objects have added their tittle to the belief in thunderbolts. In the Himalayas, for example, where awful thunderstorms are always occurring as common objects of the country, the torrents which follow them tear out of the loose soil fossil bones and tusks and teeth, which are universally looked upon as lightning-stones. The nodules of pyrites, often picked up on beaches, with their false appearance of having been melted by intense heat, pass muster easily with children and sailor folk for the genuine thunderbolts. But the grand upholder of the belief, the one true undeniable reality which has kept alive the thunderbolt even in a wicked and sceptical age, is, beyond all question, the occasional falling of meteoric stones. Your meteor is an incontrovertible fact; there is no getting over him; in the British Museum itself you will find him duly classified and labelled and catalogued. Here, surely, we have the ultimate substratum of the thunderbolt myth. To be sure, meteors have no kind of natural connection with thunderstorms; they may fall anywhere and at any time; but to object thus is to be hypercritical. A stone that falls from heaven, no matter how or when, is quite good enough to be considered as a thunderbolt.
Meteors, indeed, might very easily be confounded with lightning, especially by people who already have the full-blown conception of a thunderbolt floating about vaguely in their brains. The meteor leaps upon the earth suddenly with a rushing noise; it is usually red-hot when it falls, by friction against the air; it is mostly composed of native iron and other heavy metallic bodies; and it does its best to bury itself in the ground in the most orthodox and respectable manner. The man who sees this parlous monster come whizzing through the clouds from planetary space, making a fiery track like a great dragon as it moves rapidly across the sky, and finally ploughing its way into the earth in his own back garden, may well be excused for regarding it as a fine specimen of the true antique thunderbolt. The same virtues which belong to the buried stone are in some other places claimed for meteoric iron, small pieces of which are worn as charms, specially useful in protecting the wearer against thunder, lightning, and evil incantations. In many cases miraculous images have been hewn out of the stones that have fallen from heaven; and in others the meteorite itself is carefully preserved or worshipped as the actual representative of god or goddess, saint or madonna. The image that fell down from Jupiter may itself have been a mass of meteoric iron.
Both meteorites and stone hatchets, as well as all other forms of thunderbolt, are in excellent repute as amulets, not only against lightning, but against the evil eye generally. In Italy they protect the owner from thunder, epidemics, and cattle disease, the last two of which are well known to be caused by witchcraft; while Prospero in the 'Tempest' is a surviving proof how thunderstorms, too, can be magically produced. The tongues of sheep-bells ought to be made of meteoric iron or of elf-bolts, in order to insure the animals against foot-and-mouth disease or death by storm. Built into walls or placed on the threshold of stables, thunderbolts are capital preventives of fire or other damage, though not perhaps in this respect quite equal to a rusty horseshoe from a prehistoric battlefield. Thrown into a well they purify the water; and boiled in the drink of diseased sheep they render a cure positively certain. In Cornwall thunderbolts are a sovereign remedy for rheumatism; and in the popular pharmacopoeia of Ireland they have been employed with success for ophthalmia, pleurisy, and many other painful diseases. If finely powdered and swallowed piecemeal, they render the person who swallows them invulnerable for the rest of his lifetime. But they cannot conscientiously be recommended for dyspepsia and other forms of indigestion.
As if on purpose to confuse our already very vague ideas about thunderbolts, there is one special kind of lightning which really seems intentionally to simulate a meteorite, and that is the kind known as fire-balls or (more scientifically) globular lightning. A fire-ball generally appears as a sphere of light, sometimes only as big as a Dutch cheese, sometimes as large as three feet in diameter. It moves along very slowly and demurely through the air, remaining visible for a whole minute or two together; and in the end it generally bursts up with great violence, as if it were a London railway station being experimented upon by Irish patriots. At Milan one day a fire-ball of this description walked down one of the streets so slowly that a small crowd walked after it admiringly, to see where it was going. It made straight for a church steeple, after the common but sacrilegious fashion of all lightning, struck the gilded cross on the topmost pinnacle, and then immediately vanished, like a Virgilian apparition, into thin air.
A few years ago, too, Dr. Tripe was watching a very severe thunderstorm, when he saw a fire-ball come quietly gliding up to him, apparently rising from the earth rather than falling towards it. Instead of running away, like a practical man, the intrepid doctor held his ground quietly and observed the fiery monster with scientific nonchalance. After continuing its course for some time in a peaceful and regular fashion, however, without attempting to assault him, it finally darted off at a tangent in another direction, and turned apparently into forked lightning. A fire-ball, noticed among the Glendowan Mountains in Donegal, behaved even more eccentrically, as might be expected from its Irish antecedents. It first skirted the earth in a leisurely way for several hundred yards like a cannon-ball; then it struck the ground, ricochetted, and once more bounded along for another short spell; after which it disappeared in the boggy soil, as if it were completely finished and done for. But in another moment it rose again, nothing daunted, with Celtic irrepressibility, several yards away, pursued its ghostly course across a running stream (which shows, at least, there could have been no witchcraft in it), and finally ran to earth for good in the opposite bank, leaving a round hole in the sloping peat at the spot where it buried itself. Where it first struck, it cut up the peat as if with a knife, and made a broad deep trench which remained afterwards as a witness of its eccentric conduct. If the person who observed it had been of a superstitious turn of mind we should have had here one of the finest and most terrifying ghost stories on the entire record, which would have made an exceptionally splendid show in the 'Transactions of the Society for Psychical Research.' Unfortunately, however, he was only a man of science, ungifted with the precious dower of poetical imagination; so he stupidly called it a remarkable fire-ball, measured the ground carefully like a common engineer, and sent an account of the phenomenon to that far more prosaic periodical, the 'Quarterly Journal of the Meteorological Society.' Another splendid apparition thrown away recklessly, for ever!
There is a curious form of electrical discharge, somewhat similar to the fire-ball but on a smaller scale, which may be regarded as the exact opposite of the thunderbolt, inasmuch as it is always quite harmless. This is St. Elmo's fire, a brush of lambent light, which plays around the masts of ships and the tops of trees, when clouds are low and tension great. It is, in fact, the equivalent in nature of the brush discharge from an electric machine. The Greeks and Romans looked upon this lambent display as a sign of the presence of Castor and Pollux, 'fratres Helenae, lucida sidera,' and held that its appearance was an omen of safety, as everybody who has read the 'Lays of Ancient Rome' must surely remember. The modern name, St. Elmo's fire, is itself a curiously twisted and perversely Christianised reminiscence of the great twin brethren; for St. Elmo is merely a corruption of Helena, made masculine and canonised by the grateful sailors. It was as Helen's brothers that they best knew the Dioscuri in the good old days of the upper empire; and when the new religion forbade them any longer to worship those vain heathen deities, they managed to hand over the flames at the masthead to an imaginary St. Elmo, whose protection stood them in just as good stead as that of the original alternate immortals.
Finally, the effects of lightning itself are sometimes such as to produce upon the mind of an impartial but unscientific beholder the firm idea that a bodily thunderbolt must necessarily have descended from heaven. In sand or rock, where lightning has struck, it often forms long hollow tubes, known to the calmly discriminating geological intelligence as fulgurites, and looking for all the world like gigantic drills such as quarrymen make for putting in a blast. They are produced, of course, by the melting of the rock under the terrific heat of the electric spark; and they grow narrower and narrower as they descend till they finally disappear. But to a casual observer, they irresistibly suggest the notion that a material weapon has struck the ground, and buried itself at the bottom of the hole. The summit of Little Ararat, that weather-beaten and many-fabled peak (where an enterprising journalist not long ago discovered the remains of Noah's Ark), has been riddled through and through by frequent lightnings, till the rock is now a mere honeycombed mass of drills and tubes, like an old target at the end of a long day's constant rifle practice. Pieces of the red trachyte from the summit, a foot long, have been brought to Europe, perforated all over with these natural bullet marks, each of them lined with black glass, due to the fusion of the rock by the passage of the spark. Specimens of such thunder-drilled rock may be seen in most geological museums. On some which Humboldt collected from a peak in Mexico, the fused slag from the wall of the tube has overflowed on to the surrounding surface, thus conclusively proving (if proof were necessary) that the holes are due to melting heat alone, and not to the passage of any solid thunderbolt.
But it was the introduction and general employment of lightning-rods that dealt a final deathblow to the thunderbolt theory. A lightning-conductor consists essentially of a long piece of metal, pointed at the end whose business it is, not so much (as most people imagine) to carry off the flash of lightning harmlessly, should it happen to strike the house to which the conductor is attached, but rather to prevent the occurrence of a flash at all, by gradually and gently drawing off the electricity as fast as it gathers before it has had time to collect in sufficient force for a destructive discharge. It resembles in effect an overflow pipe which drains off the surplus water of a pond as soon as it runs in, in such a manner as to prevent the possibility of an inundation, which might occur if the water were allowed to collect in force behind a dam or embankment. It is a flood-gate, not a moat: it carries away the electricity of the air quietly to the ground, without allowing it to gather in sufficient amount to produce a flash of lightning. It might thus be better called a lightning-preventer than a lightning-conductor: it conducts electricity, but it prevents lightning. At first, all lightning-rods used to be made with knobs on the top, and then the electricity used to collect at the surface until the electric force was sufficient to cause a spark. In those happy days, you had the pleasure of seeing that the lightning was actually being drawn off from your neighbourhood piecemeal. Knobs, it was held, must be the best things, because you could incontestably see the sparks striking them with your own eyes. But as time went on, electricians discovered that if you fixed a fine metal point to the conductor of an electric machine it was impossible to get up any appreciable charge because the electricity kept always leaking out by means of the point. Then it was seen that if you made your lightning-rods pointed at the end, you would be able in the same way to dissipate your electricity before it ever had time to come to a head in the shape of lightning. From that moment the thunderbolt was safely dead and buried. It was urged, indeed, that the attempt thus to rob Heaven of its thunders was wicked and impious; but the common-sense of mankind refused to believe that absolute omnipotence could be sensibly defied by twenty yards of cylindrical iron tubing. Thenceforth the thunderbolt ceased to exist, save in poetry, country houses, and the most rural circles; even the electric fluid was generally relegated to the provincial press, where it still keeps company harmoniously with caloric, the devouring element, nature's abhorrence of a vacuum, and many other like philosophical fossils: while lightning itself, shorn of its former glories, could no longer wage impious war against cathedral towers, but was compelled to restrict itself to blasting a solitary rider now and again in the open fields, or drilling more holes in the already crumbling summit of Mount Ararat. Yet it will be a thousand years more, in all probability, before the last thunderbolt ceases to be shown as a curiosity here and there to marvelling visitors, and takes its proper place in some village museum as a belemnite, a meteoric stone, or a polished axe-head of our neolithic ancestors. Even then, no doubt, the original bolt will still survive as a recognised property in the stock-in-trade of every well-equipped poet.
Place, the garden. Time, summer. Dramatis personae, a couple of small brown garden-ants, and a lazy clustering colony of wee green 'plant-lice,' or 'blight,' or aphides. The exact scene is usually on the young and succulent branches of a luxuriant rose-bush, into whose soft shoots the aphides have deeply buried their long trunk-like snouts, in search of the sap off which they live so contentedly through their brief lifetime. To them, enter the two small brown ants, their lawful possessors; for ants, too, though absolutely unrecognised by English law ('de minimis non curat lex,' says the legal aphorism), are nevertheless in their own commonwealth duly seised of many and various goods and chattels; and these same aphides, as everybody has heard, stand to them in pretty much the same position as cows stand to human herdsmen. Throw in for sole spectator a loitering naturalist, and you get the entire mise-en-scene of a quaint little drama that works itself out a dozen times among the wilted rose-trees beneath the latticed cottage windows every summer morning.
It is a delightful sight to watch the two little lilliputian proprietors approaching and milking these their wee green motionless cattle. First of all, the ants quickly scent their way with protruded antennae (for they are as good as blind, poor things!) up the prickly stem of the rose-bush, guided, no doubt, by the faint perfume exhaled from the nectar above them. Smelling their road cautiously to the ends of the branches, they soon reach their own particular aphides, whose bodies they proceed gently to stroke with their outstretched feelers, and then stand by quietly for a moment in happy anticipation of the coming dinner. Presently, the obedient aphis, conscious of its lawful master's friendly presence, begins slowly to emit from two long horn-like tubes near the centre of its back a couple of limpid drops of a sticky pale yellow fluid. Honey-dew our English rustics still call it, because, when the aphides are not milked often enough by ants, they discharge it awkwardly of their own accord, and then it falls as a sweet clammy dew upon the grass beneath them. The ant, approaching the two tubes with cautious tenderness, removes the sweet drops without injuring in any way his little protege, and then passes on to the next in order of his tiny cattle, leaving the aphis apparently as much relieved by the process as a cow with a full hanging udder is relieved by the timely attention of the human milkmaid.
Evidently, this is a case of mutual accommodation in the political economy of the ants and aphides: a free interchange of services between the ant as consumer and the aphis as producer. Why the aphides should have acquired the curious necessity for getting rid of this sweet, sticky, and nutritious secretion nobody knows with certainty; but it is at least quite clear that the liquid is a considerable nuisance to them in their very sedentary and monotonous existence—a waste product of which they are anxious to disembarrass themselves as easily as possible—and that while they themselves stand to the ants in the relation of purveyors of food supply, the ants in return stand to them in the relation of scavengers, or contractors for the removal of useless accumulations.
Everybody knows the aphides well by sight, in one of their forms at least, the familiar rose aphis; but probably few people ever look at them closely and critically enough to observe how very beautiful and wonderful is the organisation of their tiny limbs in all its exquisite detail. If you pick off one good-sized wingless insect, however, from a blighted rose-leaf, and put him on a glass slide under a low power of the microscope, you will most likely be quite surprised to find what a lovely little creature it is that you have been poisoning wholesale all your life long with diluted tobacco-juice. His body is so transparent that you can see through it by transmitted light: a dainty glass globe, you would say, of emerald green, set upon six tapering, jointed, hairy legs, and provided in front with two large black eyes of many facets, and a pair of long and very flexible antennae, easily moved in any direction, but usually bent backward when the creature is at rest so as to reach nearly to his tail as he stands at ease upon his native rose-leaf. There are, however, two other features about him which specially attract attention, as being very characteristic of the aphides and their allies among all other insects. In the first place, his mouth is provided with a very long snout or proboscis, classically described as a rostrum, with which he pierces the outer skin of the rose-shoot where he lives, and sucks up incessantly its sweet juices. This organ is common to the aphis with all the other bugs and plant-lice. In the second place, he has half-way down his back (or a little more) a pair of very peculiar hollow organs, the honey tubes, from which exudes that singular secretion, the honey-dew. These tubes are not found in quite all species of aphides, but they are very common among the class, and they form by far the most conspicuous and interesting organs in all those aphides which do possess them.
The life-history of the rose-aphis, small and familiar as is the insect itself, forms one of the most marvellous and extraordinary chapters in all the fairy tales of modern science. Nobody need wonder why the blight attacks his roses so persistently when once he has learnt the unusual provision for exceptional fertility in the reproduction of these insect plagues. The whole story is too long to give at full length, but here is a brief recapitulation of a year's generations of common aphides.
In the spring, the eggs of last year's crop, which have been laid by the mothers in nooks and crannies out of reach of the frost, are quickened into life by the first return of warm weather, and hatch out their brood of insects. All this brood consists of imperfect females, without a single male among them; and they all fasten at once upon the young buds of their native bush, where they pass a sluggish and uneventful existence in sucking up the juice from the veins on the one hand, and secreting honey-dew upon the other. Four times they moult their skins, these moults being in some respects analogous to the metamorphosis of the caterpillar into chrysalis and butterfly. After the fourth moult, the young aphides attain maturity; and then they give origin, parthenogenetically, to a second brood, also of imperfect females, all produced without any fathers. This second brood brings forth in like manner a third generation, asexual, as before; and the same process is repeated without intermission as long as the warm weather lasts. In each case, the young simply bud out from the ovaries of the mothers, exactly as new crops of leaves bud out from the rose-branch on which they grow. Eleven generations have thus been observed to follow one another rapidly in a single summer; and indeed, by keeping the aphides in a warm room, one may even make them continue their reproduction in this purely vegetative fashion for as many as four years running. But as soon as the cold weather begins to set in, perfect male and female insects are produced by the last swarm of parthenogenetic mothers; and these true females, after being fertilised, lay the eggs which remain through the winter, and from which the next summer's broods have to begin afresh the wonderful cycle. Thus, only one generation of aphides, out of ten or eleven, consists of true males and females: all the rest are false females, producing young by a process of budding.
Setting aside for the present certain special modifications of this strange cycle which have been lately described by M. Jules Lichtenstein, let us consider for a moment what can be the origin and meaning of such an unusual and curious mode of reproduction.
The aphides are on the whole the most purely inactive and vegetative of all insects, unless indeed we except a few very debased and degraded parasites. They fasten themselves early in life on to a particular shoot of a particular plant; they drink in its juices, digest them, grow, and undergo their incomplete metamorphoses; they produce new generations with extraordinary rapidity; and they vegetate, in fact, almost as much as the plant itself upon which they are living. Their existence is duller than that of the very dullest cathedral city. They are thus essentially degenerate creatures: they have found the conditions of life too easy for them, and they have reverted to something so low and simple that they are almost plant-like in some of their habits and peculiarities.
The ancestors of the aphides were free winged insects; and, in certain stages of their existence, most living species of aphides possess at least some winged members. On the rose-bush, you can generally pick off a few such larger winged forms, side by side with the wee green wingless insects. But creatures which have taken to passing most of their life upon a single spot on a single plant hardly need the luxury of wings; and so, in nine cases out of ten, natural selection has dispensed with those needless encumbrances. Even the legs are comparatively little wanted by our modern aphides, which only require them to walk away in a stately sleepy manner when rudely disturbed by man, lady-birds, or other enemies; and indeed the legs are now very weak and feeble, and incapable of walking for more than a short distance at a time under exceptional provocation. The eyes remain, it is true; but only the big ones: the little ocelli at the top of the head, found amongst so many of their allies, are quite wanting in all the aphides. In short, the plant-lice have degenerated into mere mouths and sacks for sucking and storing food from the tissues of plants, provided with large honey-tubes for getting rid of the waste sugar.
Now, the greater the amount of food any animal gets, and the less the amount of expenditure it performs in muscular action, the greater will be the surplus it has left over for the purposes of reproduction. Eggs or young, in fact, represent the amount thus left over after all the wants of the body have been provided for. But in the rose-aphis the wants of the body, when once the insect has reached its full growth, are absolutely nothing; and it therefore then begins to bud out new generations in rapid succession as fast as ever it can produce them. This is strictly analogous to what we see every day taking place in all the plants around us. New leaves are produced one after another, as fast as material can be supplied for their nutrition, and each of these new leaves is known to be a separate individual, just as much as the individual aphis. At last, however, a time comes when the reproductive power of the plant begins to fail, and then it produces flowers, that is to say stamens (male) and pistils (female), whose union results in fertilisation and the subsequent outgrowth of fruit and seeds. Thus a year's cycle of the plant-lice exactly answers to the life-history of an ordinary annual. The eggs correspond to the seeds; the various generations of aphides budding out from one another by parthenogenesis correspond to the leaves budded out by one another throughout the summer; and the final brood of perfect males and females answers to the flower with its stamen and pistils, producing the seeds, as they produce the eggs, for setting up afresh the next year's cycle.
This consideration, I fancy, suggests to us the most probable explanation of the honey-tubes and honey-dew. Creatures that eat so much and reproduce so fast as the aphides are rapidly sucking up juices all the time from the plant on which they fasten, and converting most of the nutriment so absorbed into material for fresh generations. That is how they swarm so fast over all our shrubs and flowers. But if there is any one kind of material in their food in excess of their needs, they would naturally have to secrete it by a special organ developed or enlarged for the purpose. I don't mean that the organ would or could be developed all at once, by a sudden effort, but that as the habit of fixing themselves upon plants and sucking their juices grew from generation to generation with these descendants of originally winged insects, an organ for permitting the waste product to exude must necessarily have grown side by side with it. Sugar seems to have been such a waste product, contained in the juices of the plant to an extent beyond what the aphides could assimilate or use up in the production of new broods; and this sugar is therefore secreted by special organs, the honey-tubes. One can readily imagine that it may at first have escaped in small quantities, and that two pores on their last segment but two may have been gradually specialised into regular secreting organs, perhaps under the peculiar agency of the ants, who have regularly appropriated so many kinds of aphides as miniature milch cows.
So completely have some species of ants come to recognise their own proprietary interest in the persons of the aphides, that they provide them with fences and cow-sheds on the most approved human pattern. Sometimes they build up covered galleries to protect their tiny cattle; and these galleries lead from the nest to the place where the aphides are fixed, and completely enclose the little creatures from all chance of harm. If intruders try to attack the farmyard, the ants drive them away by biting and lacerating them. Sir John Lubbock, who has paid great attention to the mutual relations of ants and aphides, has even shown that various kinds of ants domesticate various species of aphis. The common brown garden-ant, one of the darkest skinned among our English races, 'devotes itself principally to aphides which frequent twigs and leaves'; especially, so far as I have myself observed, the bright green aphis of the rose, and the closely allied little black aphis of the broad bean. On the other hand a nearly related reddish ant pays attention chiefly to those aphides which live on the bark of trees, while the yellow meadow-ants, a far more subterranean species, keep flocks and herds of the like-minded aphides which feed upon the roots of herbs and grasses.
Sir John Lubbock, indeed, even suggests—and how the suggestion would have charmed 'Civilisation' Buckle!—that to this difference of food and habit the distinctive colours of the various species may very probably be due. The ground which he adduces for this ingenious idea is a capital example of the excellent use to which out-of-the-way evidence may be cleverly put by a competent evolutionary thinker. 'The Baltic amber,' he says, 'contains among the remains of many other insects a species of ant intermediate between our small brown garden-ants and the little yellow meadow-ants. This is possibly the stock from which these and other allied species are descended. One is tempted to suggest that the brown species which live so much in the open air, and climb up trees and bushes, have retained and even deepened their dark colour; while others, such as the yellow meadow-ant, which lives almost entirely below ground, have become much paler.' He might have added, as confirmatory evidence, the fact that the perfect winged males and females of the yellow species, which fly about freely during the brief honeymoon in the open air, are even darker in hue than the brown garden-ant. But how the light colour of the neuter workers gets transmitted through these dusky parents from one generation to another is part of that most insoluble crux of all evolutionary reasoning—the transmission of special qualities to neuters by parents who have never possessed them.
This last-mentioned yellow meadow-ant has carried the system of domestication further in all probability than any other species among its congeners. Not only do the yellow ants collect the root-feeding aphides in their own nests, and tend them as carefully as their own young, but they also gather and guard the eggs of the aphides, which, till they come to maturity, are of course quite useless. Sir John Lubbock found that his yellow ants carried the winter eggs of a species of aphis into their nest, and there took great care of them. In the spring, the eggs hatched out; and the ants actually carried the young aphides out of the nest again, and placed them on the leaves of a daisy growing in the immediate neighbourhood. They then built up a wall of earth over and round them. The aphides went on in their usual lazy fashion throughout the summer, and in October they laid another lot of eggs, precisely like those of the preceding autumn. This case, as the practised observer himself remarks, is an instance of prudence unexampled, perhaps, in the animal kingdom, outside man. 'The eggs are laid early in October on the food-plant of the insect. They are of no direct use to the ants; yet they are not left where they are laid, exposed to the severity of the weather and to innumerable dangers, but brought into their nests by the ants, and tended by them with the utmost care through the long winter months until the following March, when the young ones are brought out again and placed on the young shoots of the daisy.' Mr. White of Stonehouse has also noted an exactly similar instance of formican providence.
The connection between so many ants and so many species of the aphides being so close and intimate, it does not seem extravagant to suppose that the honey-tubes in their existing advanced form at least may be due to the deliberate selective action of these tiny insect-breeders. Indeed, when we consider that there are certain species of beetles which have never been found anywhere except in ants' nests, it appears highly probable that these domesticated forms have been produced by the ants themselves, exactly as the dog, the sheep, and the cow, in their existing types, have been produced by deliberate human selection. If this be so, then there is nothing very out-of-the-way in the idea that the ants have also produced the honey-tubes of aphides by their long selective action. It must be remembered that ants, in point of antiquity, date back, under one form or another, no doubt to a very remote period of geological time. Their immense variety of genera and species (over a thousand distinct kinds are known) show them to be a very ancient family, or else they would not have had time to be specially modified in such a wonderful multiformity of ways. Even as long ago as the time when the tertiary deposits of Oeningen and Radoboj were laid down, Dr. Heer of Zurich has shown that at least eighty-three distinct species of ants already existed; and the number that have left no trace behind is most probably far greater. Some of the beetles and woodlice which ants domesticate in their nests have been kept underground so long that they have become quite blind—that is to say, have ceased altogether to produce eyes, which would be of no use to them in their subterranean galleries; and one such blind beetle, known as Claviger, has even lost the power of feeding itself, and has to be fed by its masters from their own mandibles. Dr. Taschenberg enumerates 300 species of true ants'-nest insects, mostly beetles, in Germany alone; and M. Andre gives a list of 584 kinds, habitually found in association with ants in one country or another. Compared with these singular results of formican selection, the mere production or further development of the honey-tubes appears to be a very small matter.
But what good do the aphides themselves derive from the power of secreting honey-dew? For we know now that no animal or plant is ever provided with any organ or part merely for the benefit of another creature: the advantage must at least be mutual. Well, in the first place, it is likely that, in any case, the amount of sugary matter in the food of the aphides is quite in excess of their needs; they assimilate the nitrogenous material of the sap, and secrete its saccharine material as honey-dew. That, however, would hardly account for the development of special secretory ducts, like the honey-tubes, in which you can actually see the little drops of honey rolling, under the microscope. But the ants are useful allies to the aphides, in guarding them from another very dangerous type of insect. They are subject to the attacks of an ichneumon fly, which lays its eggs in them, meaning its larvae to feed upon their living bodies; and the ants watch over the aphides with the greatest vigilance, driving off the ichneumons whenever they approach their little proteges.
Many other insects besides ants, however, are fond of the sweet secretions of the aphides, and it is probable that the honey-dew thus acts to some extent as a preservative of the species, by diverting possible foes from the insects themselves, to the sugary liquid which they distil from their food-plants. Having more than enough and to spare for all their own needs, and the needs of their offspring, the plant-lice can afford to employ a little of their nutriment as a bribe to secure them from the attacks of possible enemies. Such compensatory bribes are common enough in the economy of nature. Thus our common English vetch secretes a little honey on the stipules or wing-like leaflets on the stem, and so distracts thieving ants from committing their depredations upon the nectaries in the flowers, which are intended for the attraction of the fertilising bees; and a South American acacia, as Mr. Belt has shown, bears hollow thorns and produces honey from a gland in each leaflet, in order to allure myriads of small ants which nest in the thorns, eat the honey, and repay the plant by driving away their leaf-cutting congeners. Indeed, as they sting violently, and issue forth in enormous swarms whenever the plant is attacked, they are even able to frighten off browsing cattle from their own peculiar acacia.
Aphides, then, are essentially degraded insects, which have become almost vegetative in their habits, and even in their mode of reproduction, but which still retain a few marks of their original descent from higher and more locomotive ancestors. Their wings, especially, are useful to the perfect forms in finding one another, and to the imperfect ones in migrating from one plant to its nearest neighbours, where they soon become the parents of fresh hordes in rapid succession. Hence various kinds of aphides are among the most dreaded plagues of agriculturists. The 'fly,' which Kentish farmers know so well on hops, is an aphis specialised for that particular bine; and, when once it appears in the gardens, it spreads with startling rapidity from one end of the long rows to the other. The phylloxera which has spoilt the French vineyards is a root-feeding form that attacks the vine, and kills or maims the plant terribly, by sucking the vital juices on their way up into the fresh-forming foliage. The 'American blight' on apple trees is yet another member of the same family, a wee creeping cottony creature that hides among the fissures of the bark, and drives its very long beak far down into the green sappy layer underlying the dead outer covering. In fact, almost all the best-known 'blights' and bladder-forming insects are aphides of one kind or another, affecting leaves, or stalks, or roots, or branches.
It is one of the most remarkable examples of the limitation of human powers that while we can easily exterminate large animals like the wolf and the bear in England, or the puma and the wolverine in the settled States of America, we should be so comparatively weak against the Colorado beetle or the fourteen-year locust, and so absolutely powerless against the hop-fly, the turnip-fly, and the phylloxera. The smaller and the more insignificant our enemy, viewed individually, the more difficult is he to cope with in the mass. All the elephants in the world could have been hunted down and annihilated, in all probability, with far less labour than has been expended upon one single little all but microscopic parasite in France alone. The enormous rapidity of reproduction in the family of aphides is the true cause of our helplessness before them. It has been calculated that a single aphis may during its own lifetime become the progenitor of 5,904,900,000 descendants. Each imperfect female produces about ninety young ones, and lives long enough to see its children's children to the fifth generation. Now, ninety multiplied by ninety four times over gives the number above stated. Of course, this makes no allowance for casualties which must be pretty frequent: but even so, the sum-total of aphides produced within a small garden in a single summer must be something very extraordinary.
It is curious, too, that aphides on the whole seem to escape the notice of insect-eating birds very tolerably. I cannot, in fact, discover that birds ever eat them, their chief real enemy being the little lizard-like larva of the lady-bird, which devours them everywhere greedily in immense numbers. Indeed, aphides form almost the sole food of the entire lady-bird tribe in their earlier stages of existence; and there is no better way of getting rid of blight on roses and other garden plants than to bring in a good boxful of these active and voracious little grubs from the fields and hedges. They will pounce upon the aphides forthwith as a cat pounces upon the mice in a well-stocked barn or farmyard. The two-spotted lady-bird in particular is the determined exterminator of the destructive hop-fly, and is much beloved accordingly by Kentish farmers. No doubt, one reason why birds do not readily see the aphis of the rose and most other species is because of their prevailing green tint, and the close way in which they stick to the leaves or shoots on whose juices they are preying. But in the case of many black and violet species, this protection of imitative colour is wanting, and yet the birds do not seem to care for the very conspicuous little insects on the broad bean, for example, whose dusky hue makes them quite noticeable in large masses. Here there may very likely be some special protection of nauseous taste in the aphides themselves (I will confess that I have not ventured to try the experiment in person), as in many other instances we know that conspicuously-coloured insects advertise their nastiness, as it were, to the birds by their own integuments, and so escape being eaten in mistake for any of their less protected relatives.
On the other hand, it seems pretty clear that certain plants have efficiently armed themselves against the aphides, in turn, by secreting bitter or otherwise unpleasant juices. So far as I can discover, the little plunderers seldom touch the pungent 'nasturtiums' or tropsaelums of our flower-gardens, even when these grow side by side with other plants on which the aphides are swarming. Often, indeed, I find winged forms upon the leaf-stem of a nasturtium, having come there evidently in hopes of starting a new colony; but usually in a dead or dying condition—the pungent juice seems to have poisoned them. So, too, spinach and lettuce may be covered with blight, while the bitter spurges, the woolly-leaved arabis, and the strong-scented thyme close by are utterly untouched. Plants seem to have acquired all these devices, such as close networks of hair upon the leaves, strong essences, bitter or pungent juices, and poisonous principles, mainly as deterrents for insect enemies, of which caterpillars and plant-lice are by far the most destructive. It would be unpardonable, of course, to write about honey-dew without mentioning tobacco; and I may add parenthetically that aphides are determined anti-tobacconists, nicotine, in fact, being a deadly poison to them. Smoking with tobacco, or sprinkling with tobacco-water, are familiar modes of getting rid of the unwelcome intruders in gardens. Doubtless this peculiar property of the tobacco plant has been developed as a prophylactic against insect enemies: and if so, we may perhaps owe the weed itself, as a smokable leaf, to the little aphides. Granting this hypothetical connection, the name of honey-dew would indeed be a peculiarly appropriate one. I may mention in passing that tobacco is quite fatal to almost all insects, a fact which I present gratuitously to the blowers of counterblasts, who are at liberty to make whatever use they choose of it. Quassia and aloes are also well-known preventives of fly or blight in gardens.
The most complete life-history yet given of any member of the aphis family is that which M. Jules Lichtenstein has worked out with so much care in the case of the phylloxera of the oak-tree. In April, the winter eggs of this species, laid in the bark of an oak, each hatch out a wingless imperfect female, which M. Lichtenstein calls the foundress. After moulting four times, the foundress produces, by parthenogenesis, a number of false eggs, which it fastens to the leaf-stalks and under side of the foliage. These false eggs hatch out a larval form, wingless, but bigger than any of the subsequent generations; and the larvae so produced themselves once more give origin to more larvae, which acquire wings, and fly away from the oak on which they were born to another of a different species in the same neighbourhood. There these larvae of the second crop once more lay false eggs, from which the third larval generation is developed. This brood is again wingless, and it proceeds at once to bud out several generations more, by internal gemmation, as long as the warm weather lasts. According to M. Lichtenstein, all previous observations have been made only on aphides of this third type; and he maintains that every species in the whole family really undergoes an analogous alternation of generations. At last, when the cold weather begins to set in, a fourth larval form appears, which soon obtains wings, and flies back to the same kind of oak on which the foundresses were first hatched out, all the intervening generations having passed their lives in sucking the juices of the other oak to which the second larval form migrated. The fourth type here produce perfect male and female insects, which are wingless, and have no sucking apparatus. The females, after being impregnated, lay a single egg each, which they hide in the bark, where it remains during the winter, till in spring it once more hatches out into a foundress, and the whole cycle begins over again. Whether all the aphides do or do not pass through corresponding stages is not yet quite certain. But Kentish farmers believe that the hop-fly migrates to hop-bines from plum-trees in the neighbourhood; and M. Lichtenstein considers that such migrations from one plant to another are quite normal in the family. We know, indeed, that many great plagues of our crops are thus propagated, sometimes among closely related plants, but sometimes also among the most widely separated species. For example, turnip-fly (which is not an aphis, but a small beetle) always begins its ravages (as Miss Ormerod has abundantly shown) upon a plot of charlock, and then spreads from patches of that weed to the neighbouring turnips, which are slightly diverse members of the same genus. But, on the other hand, it has long been well known that rust in wheat is specially connected with the presence of the barberry bush; and it has recently been proved that the fungus which produces the disease passes its early stages on the barberry leaves, and only migrates in later generations to the growing wheat. This last case brings even more prominently into light than ever the essential resemblance of the aphides to plant-parasites.
THE MILK IN THE COCO-NUT
For many centuries the occult problem how to account for the milk in the coco-nut has awakened the profoundest interest alike of ingenuous infancy and of maturer scientific age. Though it cannot be truthfully affirmed of it, as of the cosmogony or creation of the world, in the 'Vicar of Wakefield,' that it 'has puzzled the philosophers of all ages' (for Sanchoniathon was certainly ignorant of the very existence of that delicious juice, and Manetho doubtless went to his grave without ever having tasted it fresh from the nut under a tropical verandah), yet it may be safely asserted that for the last three hundred years the philosopher who has not at some time or other of his life meditated upon that abstruse question is unworthy of such an exalted name. The cosmogony and the milk in the coco-nut are, however, a great deal closer together in thought than Sanchoniathon or Manetho, or the rogue who quoted them so glibly, is ever at all likely, in his wildest moments, to have imagined.
The coco-nut, in fact, is a subject well deserving of the most sympathetic treatment at the gentle hands of grateful humanity. No other plant is useful to us in so many diverse and remarkable manners. It has been truly said of that friend of man, the domestic pig, that he is all good, from the end of his snout to the tip of his tail; but even the pig, though he furnishes us with so many necessaries or luxuries—from tooth-brushes to sausages, from ham to lard, from pepsine wine to pork pies—does not nearly approach, in the multiplicity and variety of his virtues, the all-sufficing and world-supplying coco-nut. A Chinese proverb says that there are as many useful properties in the coco-nut palm as there are days in the year; and a Polynesian saying tells us that the man who plants a coco-nut plants meat and drink, hearth and home, vessels and clothing, for himself and his children after him. Like the great Mr. Whiteley, the invaluable palm-tree might modestly advertise itself as a universal provider. The solid part of the nut supplies food almost alone to thousands of people daily, and the milk serves them for drink, thus acting as an efficient filter to the water absorbed by the roots in the most polluted or malarious regions. If you tap the flower stalk you get a sweet juice, which can be boiled down into the peculiar sugar called (in the charming dialect of commerce) jaggery; or it can be fermented into a very nasty spirit known as palm-wine, toddy, or arrack; or it can be mixed with bitter herbs and roots to make that delectable compound 'native beer.' If you squeeze the dry nut you get coco-nut oil, which is as good as lard for frying when fresh, and is 'an excellent substitute for butter at breakfast,' on tropical tables. Under the mysterious name of copra (which most of us have seen with awe described in the market reports as 'firm' or 'weak,' 'receding' or 'steady') it forms the main or only export of many Oceanic islands, and is largely imported into this realm of England, where the thicker portion is called stearine, and used for making sundry candles with fanciful names, while the clear oil is employed for burning in ordinary lamps. In the process of purification, it yields glycerine; and it enters largely into the manufacture of most better-class soaps. The fibre that surrounds the nut makes up the other mysterious article of commerce known as coir, which is twisted into stout ropes, or woven into coco-nut matting and ordinary door-mats. Brushes and brooms are also made of it, and it is used, not always in the most honest fashion, in place of real horse-hair in stuffing cushions. The shell, cut in half, supplies good cups, and is artistically carved by the Polynesians, Japanese, Hindoos, and other benighted heathen, who have not yet learnt the true methods of civilised machine-made shoddy manufacture. The leaves serve as excellent thatch; on the flat blades, prepared like papyrus, the most famous Buddhist manuscripts are written; the long mid-ribs or branches (strictly speaking, the leaf-stalks) answer admirably for rafters, posts, or fencing; the fibrous sheath at the base is a remarkable natural imitation of cloth, employed for strainers, wrappers, and native hats; while the trunk, or stem, passes in carpentry under the name of porcupine wood, and produces beautiful effects as a wonderfully coloured cabinet-makers' material. These are only a few selected instances out of the innumerable uses of the coco-nut palm.
Apart even from the manifold merits of the tree that bears it, the milk itself has many and great claims to our respect and esteem, as everybody who has ever drunk it in its native surroundings will enthusiastically admit. In England, to be sure, the white milk in the dry nuts is a very poor stuff, sickly, and strong-flavoured, and rather indigestible. But in the tropics, coco-nut milk, or, as we oftener call it there, coco-nut water, is a very different and vastly superior sort of beverage. At eleven o'clock every morning, when you are hot and tired with the day's work, your black servant, clad from head to foot in his cool clean white linen suit, brings you in a tall soda glass full of a clear, light, crystal liquid, temptingly displayed against the yellow background of a chased Benares brass-work tray. The lump of ice bobs enticingly up and down in the centre of the tumbler, or clinks musically against the edge of the glass as he carries it along. You take the cool cup thankfully and swallow it down at one long draught; fresh as a May morning, pure as an English hillside spring, delicate as—well, as coco-nut water. None but itself can be its parallel. It is certainly the most delicious, dainty, transparent, crystal drink ever invented. How did it get there, and what is it for?
In the early green stage at which coco-nuts are generally picked for household use in the tropics the shell hasn't yet solidified into a hard stony coat, but still remains quite soft enough to be readily cut through with a sharp table knife—just like young walnuts picked for pickling. If you cut one across while it's in this unsophisticated state, it is easy enough to see the arrangement of the interior, and the part borne by the milk in the development and growth of the mature nut. The ordinary tropical way of opening coco-nuts for table, indeed, is by cutting off the top of the shell and rind in successive slices, at the end where the three pores are situated, until you reach the level of the water, which fills up the whole interior. The nutty part around the inside of the shell is then extremely soft and jelly-like, so that it can be readily eaten with a spoon; but as a matter of fact very few people ever do eat the flesh at all. After their first few months in the tropics, they lose the taste for this comparatively indigestible part, and confine themselves entirely (like patients at a German spa) to drinking the water. A young coco-nut is thus seen to consist, first of a green outer skin, then of a fibrous coat, which afterwards becomes the hair, and next of a harder shell which finally gets quite woody; while inside all comes the actual seed or unripe nut itself. The office of the coco-nut water is the deposition of the nutty part around the side of the shell; it is, so to speak, the mother liquid, from which the harder eatable portion is afterwards derived. This state is not uncommon in embryo seeds. In a very young pea, for example, the inside is quite watery, and only the outer skin is at all solid, as we have all observed when green peas first come into season. But the special peculiarity of the coco-nut consists in the fact that this liquid condition of the interior continues even after the nut is ripe, and that is the really curious point about the milk in the coco-nut which does actually need accounting for.
In order to understand it one ought to examine a coco-nut in the act of budding, and to do this it is by no means necessary to visit the West Indies or the Pacific Islands; all you need to do is to ask a Covent Garden fruit salesman to get you a few 'growers.' On the voyage to England, a certain number of precocious coco-nuts, stimulated by the congenial warmth and damp of most shipholds, usually begin to sprout before their time; and these waste nuts are sold by the dealers at a low rate to East-end children and inquiring botanists. An examination of a 'grower' very soon convinces one what is the use of the milk in the coco-nut.
It must be duly borne in mind, to begin with, that the prime end and object of the nut is not to be eaten raw by the ingenious monkey, or to be converted by lordly man into coco-nut biscuits, or coco-nut pudding, but simply and solely to reproduce the coco-nut palm in sufficient numbers to future generations. For this purpose the nut has slowly acquired by natural selection a number of protective defences against its numerous enemies, which serve to guard it admirably in the native state from almost all possible animal depredators. First of all, the actual nut or seed itself consists of a tiny embryo plant, placed just inside the softest of the three pores or pits at the end of the shell, and surrounded by a vast quantity of nutritious pulp, destined to feed and support it during its earliest unprotected days, if not otherwise diverted by man or monkey. But as whatever feeds a young plant will also feed an animal, and as many animals betray a felonious desire to appropriate to their own wicked ends the food-stuffs laid up by the palm for the use of its own seedling, the coco-nut has been compelled to inclose this particularly large and rich kernel in a very solid and defensive shell. And, once more, since the palm grows at a very great height from the ground—I have seen them up to ninety feet in favourable circumstances—this shell stands a very good chance of getting broken in tumbling to the earth, so that it has been necessary to surround it with a mass of soft and yielding fibrous material, which breaks its fall, and acts as a buffer to it when it comes in contact with the soil beneath. So many protections has the coco-nut gradually devised for itself by the continuous survival of the best adapted amid numberless and endless spontaneous variations of all its kind in past time.
Now, when the coco-nut has actually reached the ground at last, and proceeds to sprout in the spot where chance (perhaps in the bodily shape of a disappointed monkey) has chosen to cast it, these numerous safeguards and solid envelopes naturally begin to prove decided nuisances to the embryo within. It starts under the great disadvantage of being hermetically sealed within a solid wooden shell, so that no water can possibly get at it to aid it as most other seeds are aided in the process of germination. Fancy yourself a seed-pea, anxious to sprout, but coated all round with a hard covering of impermeable sealing-wax, and you will be in a position faintly to appreciate the unfortunate predicament of a grower coco-nut. Natural selection, however—that deus ex machina of modern science, which can perform such endless wonders, if only you give it time enough to work in and variations enough to work upon—natural selection has come to the rescue of the unhappy plant by leaving it a little hole at the top of the shell, out of which it can push its feathery green head without difficulty. Everybody knows that if you look at the sharp end of a coco-nut you will see three little brown pits or depressions on its surface. Most people also know that two of these are firmly stopped up (for a reason to which I shall presently recur), but that the third one is only closed by a slight film or very thin shell, which can be easily bored through with a pocket knife, so as to let the milk run off before cracking the shell. So much we have all learnt during our ardent pursuit of natural knowledge on half-holidays in early life. But we probably then failed to observe that just opposite this soft hole lies a small roundish knob, imbedded in the pulp or eatable portion, which knob is in fact the embryo palm or seedling, for whose ultimate benefit the whole arrangement (in brown and green) has been invented. That is very much the way with man: he notices what concerns his own appetite, and omits all the really important parts of the whole subject. We think the use of the hole is to let out the milk; but the nut knows that its real object is to let out the seedling. The knob grows out at last into the young plantlet, and it is by means of the soft hole that it makes its escape through the shell to the air and the sunshine which it seeks without. This brings us really down at last to the true raison d'etre for the milk in the coco-nut. As the seed or kernel cannot easily get at much water from outside, it has a good supply of water laid up for it ready beforehand within its own encircling shell. The mother liquid from which the pulp or nutty part has been deposited remains in the centre, as the milk, till the tiny embryo begins to sprout. As soon as it does so, the little knob which was at first so very small enlarges rapidly and absorbs the water, till it grows out into a big spongy cellular mass, which at last almost fills up the entire shell. At the same time, its other end pushes its way out through the soft hole, and then gives birth to a growing bud at the top—the future stem and leaves—and to a number of long threads beneath—the future roots. Meanwhile, the spongy mass inside begins gradually to absorb all the nutty part, using up its oils and starches for the purpose of feeding the young plant above, until it is of an age to expand its leaves to the open tropical sunlight and shift for itself in the struggle for life. It seems at first sight very hard to understand how any tissue so solid as the pulp of coco-nut can be thus softened and absorbed without any visible cause; but in the subtle chemistry of living vegetation such a transformation is comparatively simple and easy to perform. Nature sometimes works much greater miracles than this in the same way: for example, what is called vegetable ivory, a substance so solid that it can be carved or turned only with great difficulty, is really the kernel of another palm-nut, allied to the coco-palm, and its very stony particles are all similarly absorbed during germination by the dissolving power of the young seedling.
Why, however, has the coco-nut three pores at the top instead of one, and why are two out of the three so carefully and firmly sealed up? The explanation of this strange peculiarity is only to be found in the ancestral history of the coco-nut kind. Most nuts, indeed, start in their earlier stage as if they meant to produce two or more seeds each; but as they ripen, all the seeds except one become abortive. The almond, for example, has in the flower two seeds or kernels to each nut; but in the ripe state there is generally only one, though occasionally we find an almond with two—a philipoena, as we commonly call it—just to keep in memory the original arrangement of its earlier ancestors. The reason for this is that plants whose fruits have no special protection for their seeds are obliged to produce a great many of them at once, in order that one seed in a thousand may finally survive the onslaughts of their Argus-eyed enemies; but when they learn to protect themselves by hard coverings from birds and beasts, they can dispense with some of these supernumerary seeds, and put more nutriment into each one of those that they still retain. Compare, for example, the innumerable small round seedlets of the poppyhead with the solitary large and richly stored seed of the walnut, or the tiny black specks of mustard and cress with the single compact and well-filled seed of the filbert and the acorn. To the very end, however, most nuts begin in the flower as if they meant to produce a whole capsuleful of small unstored and unprotected seeds, like their original ancestors; it is only at the last moment that they recollect themselves, suppress all their ovules except one, and store that one with all the best and oiliest food-stuffs at their disposal. The nuts, in fact, have learned by long experience that it is better to be the only son and heir of a wealthy house, set up in life with a good capital to begin upon, than to be one of a poor family of thirteen needy and unprovided children.
Now, the coco-nuts are descended from a great tribe—the palms and lilies—which have as their main distinguishing peculiarity the arrangement of parts in their flowers and fruits by threes each. For example, in the most typical flowers of this great group, there are three green outer calyx-pieces, three bright-coloured petals, three long outer stamens, three short inner stamens, three valves to the capsule, and three seeds or three rows of seeds in each fruit. Many palms still keep pretty well to this primitive arrangement, but a few of them which have specially protected or highly developed fruits or nuts have lost in their later stages the threefold disposition in the fruit, and possess only one seed, often a very large one. There is no better and more typical nut in the whole world than a coco-nut—that is to say, from our present point of view at least, though the fear of that awful person, the botanical Smelfungus, compels me to add that this is not quite technically true. Smelfungus, indeed, would insist upon it that the coco-nut is not a nut at all, and would thrill us with the delightful information, innocently conveyed in that delicious dialect of which he is so great a master, that it is really 'a drupaceous fruit with a fibrous mesocarp.' Still, in spite of Smelfungus with his nice hair-splitting distinctions, it remains true that humanity at large will still call a nut a nut, and that the coco-nut is the highest known development of the peculiar nutty tactics. It has the largest and most richly stored seed of any known plant; and this seed is surrounded by one of the hardest and most unmanageable of any known shells. Hence the coco-nut has readily been able to dispense with the three kernels which each nut used in its earlier and less developed days to produce. But though the palm has thus taken to reducing the number of its seeds in each fruit to the lowest possible point consistent with its continued existence at all, it still goes on retaining many signs of its ancient threefold arrangement. The ancestral and most deeply ingrained habits persist in the earlier stages; it is only in the mature form that the later acquired habits begin fully to predominate. Even so our own boys pass through an essentially savage childhood of ogres and fairies, bows and arrows, sugar-plums and barbaric nursery tales, as well as a romantic boyhood of mediaeval chivalry and adventure, before they steady down into that crowning glory of our race, the solid, sober, matter-of-fact, commercial British Philistine. Hence the coco-nut in its unstripped state is roughly triangular in form, its angles answering to the separate three fruits of simpler palms; and it has three pits or weak places in the shell, through which the embryos of the three original kernels used to force their way out. But as only one of them is now needed, that one alone is left soft; the other two, which would be merely a source of weakness to the plant if unprotected, are covered in the existing nut by harder shell. Doubtless they serve in part to deceive the too inquisitive monkey or other enemy, who probably concludes that if one of the pits is hard and impermeable, the other two are so likewise.
Though I have now, I hope, satisfactorily accounted for the milk in the coco-nut, and incidentally for some other matters in its economy as well, I am loth to leave the young seedling whom I have brought so far on his way to the tender mercies of the winds and storms and tropical animals, some of whom are extremely fond of his juicy and delicate shoots. Indeed, the growing point or bud of most palms is a very pleasant succulent vegetable, and one kind—the West Indian mountain cabbage—deserves a better and more justly descriptive name, for it is really much more like seakale or asparagus. I shall try to follow our young seedling on in life, therefore, so as to give, while I am about it, a fairly comprehensive and complete biography of a single flourishing coco-nut palm.
Beginning, then, with the fall of the nut from the parent-tree, the troubles of the future palm confront it at once in the shape of the nut-eating crab. This evil-disposed crustacean is common around the sea-coast of the eastern tropical islands, which is also the region mainly affected by the coco-nut palm; for coco-nuts are essentially shore-loving trees, and thrive best in the immediate neighbourhood of the sea. Among the fallen nuts, the clumsy-looking thief of a crab (his appropriate Latin name is Birgus latro) makes great and dreaded havoc. To assist him in his unlawful object he has developed a pair of front legs, with specially strong and heavy claws, supplemented by a last or tail-end pair armed only with very narrow and slender pincers. He subsists entirely upon a coco-nut diet. Setting to work upon a big fallen nut—with the husk on, coco-nuts measure in the raw state about twelve inches the long way—he tears off all the coarse fibre bit by bit, and gets down at last to the hard shell. Then he hammers away with his heavy claw on the softest eye-hole till he has pounded an opening right through it. This done he twists round his body so as to turn his back upon the coco-nut he is operating upon (crabs are never famous either for good manners or gracefulness) and proceeds awkwardly but effectually to extract all the white kernel or pulp through the breach with his narrow pair of hind pincers. Like man, too, the robber-crab knows the value of the outer husk as well as of the eatable nut itself, for he collects the fibre in surprising quantities to line his burrow, and lies upon it, the clumsy sybarite, for a luxurious couch. Alas, however, for the helplessness of crabs, and the rapacity and cunning of all-appropriating man! The spoil-sport Malay digs up the nest for the sake of the fibre it contains, which spares him the trouble of picking junk on his own account, and then he eats the industrious crab who has laid it all up, while he melts down the great lump of fat under the robber's capacious tail, and sometimes gets from it as much as a good quart of what may be practically considered as limpid coco-nut oil. Sic vos non vobis is certainly the melancholy refrain of all natural history. The coco-nut palm intends the oil for the nourishment of its own seedling; the crab feloniously appropriates it and stores it up under his capacious tail for future personal use; the Malay steals it again from the thief for his own purposes; and ten to one the Dutch or English merchant beguiles it from him with sized calico or poisoned rum, and transmits it to Europe, where it serves to lighten our nights and assist at our matutinal tub, to point a moral and adorn the present tale.
If, however, our coco-nut is lucky enough to escape the robber-crabs, the pigs, and the monkeys, as well as to avoid falling into the hands of man, and being converted into the copra of commerce, or sold from a costermonger's barrow in the chilly streets of ungenial London at a penny a slice, it may very probably succeed in germinating after the fashion I have already described, and pushing up its head through the surrounding foliage to the sunlight above. As a rule, the coco-nut has been dropped by its mother tree on the sandy soil of a sea-beach; and this is the spot it best loves, and where it grows to the stateliest height. Sometimes, however, it falls into the sea itself, and then the loose husk buoys it up, so that it floats away bravely till it is cast by the waves upon some distant coral reef or desert island. It is this power of floating and surviving a long voyage that has dispersed the coco-nut so widely among oceanic islands, where so few plants are generally to be found. Indeed, on many atolls or isolated reefs (for example, on Keeling Island) it is the only tree or shrub that grows in any quantity, and on it the pigs, the poultry, the ducks, and the land crabs of the place entirely subsist. In any case, wherever it happens to strike, the young coco-nut sends up at first a fine rosette of big spreading leaves, not raised as afterwards on a tall stem, but springing direct from the ground in a wide circle, something like a very big and graceful fern. In this early stage nothing can be more beautiful or more essentially tropical in appearance than a plantation of young coco-nuts. Their long feathery leaves spreading out in great clumps from the buried stock, and waving with lithe motion before the strong sea-breeze of the Indies, are the very embodiment of those deceptive ideal tropics which, alas, are to be found in actual reality nowhere on earth save in the artificial palm-houses at Kew, and the Casino Gardens at too entrancing Monte Carlo.
For the first two or three years the young palms must be well watered, and the soil around them opened; after which the tall graceful stem begins to rise rapidly into the open air. In this condition it may be literally said to make the tropics—those fallacious tropics, I mean, of painters and poets, of Enoch Arden and of Locksley Hall. You may observe that whenever an artist wants to make a tropical picture, he puts a group of coco-nut palms in the foreground, as much as to say, 'You see there's no deception; these are the genuine unadulterated tropics.' But as to painting the tropics without the palms, he might just as well think of painting the desert without the camels. At eight or ten years old the tree flowers, bearing blossoms of the ordinary palm type, degraded likenesses of the lilies and yuccas, greenish and inconspicuous, but visited by insects for the sake of their pollen. The flower, however, is fertilised by the wind, which carries the pollen grains from one bunch of blossoms to another. Then the nuts gradually swell out to an enormous size, and ripen very slowly, even under the brilliant tropical sun. (I will admit that the tropics are hot, though in other respects I hold them to be arrant impostors, like that precocious American youth who announced on his tenth birthday that in his opinion life wasn't all that it was cracked up to be.) But the worst thing about the coco-nut palm, the missionaries always say, is the fatal fact that, when once fairly started, it goes on bearing fruit uninterruptedly for forty years. This is very immoral and wrong of the ill-conditioned tree, because it encourages the idyllic Polynesian to lie under the palms, all day long, cooling his limbs in the sea occasionally, sporting with Amaryllis in the shade, or with the tangles of Neaera's hair, and waiting for the nuts to drop down in due time, when he ought (according to European notions) to be killing himself with hard work under a blazing sky, raising cotton, sugar, indigo, and coffee, for the immediate benefit of the white merchant, and the ultimate advantage of the British public. It doesn't enforce habits of steady industry and perseverance, the good missionaries say; it doesn't induce the native to feel that burning desire for Manchester piece-goods and the other blessings of civilisation which ought properly to accompany the propagation of the missionary in foreign parts. You stick your nut in the sand; you sit by a few years and watch it growing; you pick up the ripe fruits as they fall from the tree; and you sell them at last for illimitable red cloth to the Manchester piece-goods merchant. Nothing could be more simple or more satisfactory. And yet it is difficult to see the precise moral distinction between the owner of a coco-nut grove in the South Sea Islands and the owner of a coal-mine or a big estate in commercial England. Each lounges decorously through life after his own fashion; only the one lounges in a Russia leather chair at a club in Pall Mall, while the other lounges in a nice soft dust-heap beside a rolling surf in Tahiti or the Hawaiian Archipelago.
Curiously enough, at a little distance from the sandy levels or alluvial flats of the sea-shore, the sea-loving coco-nut will not bring its nuts to perfection. It will grow, indeed, but it will not thrive or fruit in due season. On the coast-line of Southern India, immense groves of coco-nuts fringe the shore for miles and miles together; and in some parts, as in Travancore, they form the chief agricultural staple of the whole country. 'The State has hence facetiously been called Coconutcore,' says its historian; which charmingly illustrates the true Anglo-Indian notion of what constitutes facetiousness, and ought to strike the last nail into the coffin of a competitive examination system. A good tree in full bearing should produce 120 coco-nuts in a season; so that a very small grove is quite sufficient to maintain a respectable family in decency and comfort. Ah, what a mistake the English climate made when it left off its primitive warmth of the tertiary period, and got chilled by the ice and snow of the Glacial Epoch down to its present misty and dreary wheat-growing condition! If it were not for that, those odious habits of steady industry and perseverance might never have been developed in ourselves at all, and we might be lazily picking copra off our own coco-palms, to this day, to export in return for the piece-goods of some Arctic Manchester situated somewhere about the north of Spitzbergen or the New Siberian Islands.
Even as things stand at the present day, however, it is wonderful how much use we modern Englishmen now make in our own houses of this far Eastern nut, whose very name still bears upon its face the impress of its originally savage origin. From morning to night we never leave off being indebted to it. We wash with it as old brown Windsor or glycerine soap the moment we leave our beds. We walk across our passages on the mats made from its fibre. We sweep our rooms with its brushes, and wipe our feet on it as we enter our doors. As rope, it ties up our trunks and packages; in the hands of the housemaid it scrubs our floors; or else, woven into coarse cloth, it acts as a covering for bales and furniture sent by rail or steamboat. The confectioner undermines our digestion in early life with coco-nut candy; the cook tempts us later on with coco-nut cake; and Messrs. Huntley and Palmer cordially invite us to complete the ruin with coco-nut biscuits. We anoint our chapped hands with one of its preparations after washing; and grease the wheels of our carriages with another to make them run smoothly. Finally, we use the oil to burn in our reading lamps, and light ourselves at last to bed with stearine candles. Altogether, an amateur census of a single small English cottage results in the startling discovery that it contains twenty-seven distinct articles which owe their origin in one way or another to the coco-nut palm. And yet we affect in our black ingratitude to despise the question of the milk in the coco-nut.
FOOD AND FEEDING
When a man and a bear meet together casually in an American forest, it makes a great deal of difference, to the two parties concerned at least, whether the bear eats the man or the man eats the bear. We haven't the slightest difficulty in deciding afterwards which of the two, in each particular case, has been the eater, and which the eaten. Here, we say, is the grizzly that eat the man; or, here is the man that smoked and dined off the hams of the grizzly. Basing our opinion upon such familiar and well-known instances, we are apt to take it for granted far too readily that between eating and being eaten, between the active and the passive voice of the verb edo, there exists necessarily a profound and impassable native antithesis. To swallow an oyster is, in our own personal histories, so very different a thing from being swallowed by a shark that we can hardly realise at first the underlying fundamental identity of eating with mere coalescence. And yet, at the very outset of the art of feeding, when the nascent animal first began to indulge in this very essential animal practice, one may fairly say that no practical difference as yet existed between the creature that ate and the creature that was eaten. After the man and the bear had finished their little meal, if one may be frankly metaphorical, it was impossible to decide whether the remaining being was the man or the bear, or which of the two had swallowed the other. The dinner having been purely mutual, the resulting animal represented both the litigants equally; just as, in cannibal New Zealand, the chief who ate up his brother chief was held naturally to inherit the goods and chattels of the vanquished and absorbed rival, whom he had thus literally and physically incorporated.
A jelly-speck, floating about at his ease in a drop of stagnant water under the field of a microscope, collides accidentally with another jelly-speck who happens to be travelling in the opposite direction across the same miniature ocean. What thereupon occurs? One jelly-speck rolls itself gradually into the other, so that, instead of two, there is now one; and the united body proceeds to float away quite unconcernedly, without waiting to trouble itself for a second with the profound metaphysical question, which half of it is the original personality, and which half the devoured and digested. In these minute and very simple animals there is absolutely no division of labour between part and part; every bit of the jelly-like mass is alike head and foot and mouth and stomach. The jelly-speck has no permanent limbs, but it keeps putting forth vague arms and legs every now and then from one side or the other; and with these temporary and ever-dissolving members it crawls along merrily through its tiny drop of stagnant water. If two of the legs or arms happen to knock up casually against one another, they coalesce at once, just like two drops of water on a window-pane, or two strings of treacle slowly spreading along the surface of a plate. When the jelly-speck meets any edible thing—a bit of dead plant, a wee creature like itself, a microscopic egg—it proceeds to fold its own substance slimily around it, making, as it were, a temporary mouth for the purpose of swallowing it, and a temporary stomach for the purpose of quietly digesting and assimilating it afterwards. Thus what at one moment is a foot may at the next moment become a mouth, and at the moment after that again a rudimentary stomach. The animal has no skin and no body, no outside and no inside, no distinction of parts or members, no individuality, no identity. Roll it up into one with another of its kind, and it couldn't tell you itself a minute afterwards which of the two it had really been a minute before. The question of personal identity is here considerably mixed.
But as soon as we get to rather larger creatures of the same type, the antithesis between the eater and the eaten begins to assume a more definite character. The big jelly-bag approaches a good many smaller jelly-bags, microscopic plants, and other appropriate food-stuffs, and, surrounding them rapidly with its crawling arms, envelopes them in its own substance, which closes behind them and gradually digests them. Everybody knows, by name at least, that revolutionary and evolutionary hero, the amoeba—the terror of theologians, the pet of professors, and the insufferable bore of the general reader. Well, this parlous and subversive little animal consists of a comparatively large mass of soft jelly, pushing forth slender lobes, like threads or fingers, from its own substance, and gliding about, by means of these tiny legs, over water-plants and other submerged surfaces. But though it can literally turn itself inside out, like a glove, it still has some faint beginnings of a mouth and stomach, for it generally takes in food and absorbs water through a particular part of its surface, where the slimy mass of its body is thinnest. Thus the amoeba may be said really to eat and drink, though quite devoid of any special organs for eating or drinking.
The particular point to which I wish to draw attention here, however, is this: that even the very simplest and most primitive animals do discriminate somehow between what is eatable and what isn't. The amoeba has no eyes, no nose, no mouth, no tongue, no nerves of taste, no special means of discrimination of any kind; and yet, so long as it meets only grains of sand or bits of shell, it makes no effort in any way to swallow them; but, the moment it comes across a bit of material fit for its food, it begins at once to spread its clammy fingers around the nutritious morsel. The fact is, every part of the amoeba's body apparently possesses, in a very vague form, the first beginnings of those senses which in us are specialised and confined to a single spot. And it is because of the light which the amoeba thus incidentally casts upon the nature of the specialised senses in higher animals that I have ventured once more to drag out of the private life of his native pond that already too notorious and obtrusive rhizopod.
With us lordly human beings, at the extreme opposite end in the scale of being from the microscopic jelly-specks, the art of feeding and the mechanism which provides for it have both reached a very high state of advanced perfection. We have slowly evolved a tongue and palate on the one hand, and French cooks and pate de foie gras on the other. But while everybody knows practically how things taste to us, and which things respectively we like and dislike, comparatively few people ever recognise that the sense of taste is not merely intended as a source of gratification, but serves a useful purpose in our bodily economy, in informing us what we ought to eat and what to refuse. Paradoxical as it may sound at first to most people, nice things are, in the main, things that are good for us, and nasty things are poisonous or otherwise injurious. That we often practically find the exact contrary the case (alas!) is due, not to the provisions of nature, but to the artificial surroundings in which we live, and to the cunning way in which we flavour up unwholesome food, so as to deceive and cajole the natural palate. Yet, after all, it is a pleasant gospel that what we like is really good for us, and, when we have made some small allowances for artificial conditions, it is in the main a true one also.
The sense of taste, which in the lowest animals is diffused equally over the whole frame, is in ourselves and other higher creatures concentrated in a special part of the body, namely the mouth, where the food about to be swallowed is chewed and otherwise prepared beforehand for the work of digestion. Now it is, of course, quite clear that some sort of supervision must be exercised by the body over the kind of food that is going to be put into it. Common experience teaches us that prussic acid and pure opium are undesirable food-stuffs in large quantities; that raw spirits, petroleum, and red lead should be sparingly partaken of by the judicious feeder; and that even green fruit, the bitter end of cucumber, and the berries of deadly nightshade are unsatisfactory articles of diet when continuously persisted in. If, at the very outset of our digestive apparatus, we hadn't a sort of automatic premonitory adviser upon the kinds of food we ought or ought not to indulge in, we should naturally commit considerable imprudences in the way of eating and drinking—even more than we do at present. Natural selection has therefore provided us with a fairly efficient guide in this respect in the sense of taste, which is placed at the very threshold, as it were, of our digestive mechanism. It is the duty of taste to warn us against uneatable things, and to recommend to our favourable attention eatable and wholesome ones; and, on the whole, in spite of small occasional remissness, it performs this duty with creditable success.
Taste, however, is not equally distributed over the whole surface of the tongue alike. There are three distinct regions or tracts, each of which has to perform its own special office and function. The tip of the tongue is concerned mainly with pungent and acrid tastes; the middle portion is sensitive chiefly to sweets and bitters; while the back or lower portion confines itself almost entirely to the flavours of roast meats, butter, oils, and other rich or fatty substances. There are very good reasons for this subdivision of faculties in the tongue, the object being, as it were, to make each piece of food undergo three separate examinations (like 'smalls,' 'mods,' and 'greats' at Oxford), which must be successively passed before it is admitted into full participation in the human economy. The first examination, as we shall shortly see, gets rid at once of substances which would be actively and immediately destructive to the very tissues of the mouth and body; the second discriminates between poisonous and chemically harmless food-stuffs; and the third merely decides the minor question whether the particular food is likely to prove then and there wholesome or indigestible to the particular person. The sense of taste proceeds, in fact, upon the principle of gradual selection and elimination; it refuses first what is positively destructive, next what is more remotely deleterious, and finally what is only undesirable or over-luscious.