CHAPTER II.
Ponds and rock-pools—Our necessary tackle—Wimbledon Common—Early memories—Gnat larvæ—Entomostraca and their paradoxes—Races of animals dispensing with the sterner sex—Insignificance of males—Volvox globator: is it an animal?—Plants swimming like animals—Animal retrogressions—The Dytiscus and its larva—The dragon-fly larva—Molluscs and their eggs—Polypes, and how to find them—A new polype, Hydra rubra—Nest-building fish—Contempt replaced by reverence.
The day is bright with a late autumn sun; the sky is clear with a keen autumn wind, which lashes our blood into a canter as we press against it, and the cantering blood sets the thoughts into hurrying excitement. Wimbledon Common is not far off; its five thousand acres of undulating heather, furze, and fern tempt us across it, health streaming in at every step as we snuff the keen breeze. We are tempted also to bring net and wide-mouthed jar, to ransack its many ponds for visible and invisible wonders.
Ponds, indeed, are not so rich and lovely as rock-pools; the heath is less alluring than the coast—our dear-loved coast, with its gleaming mystery, the sea, and its sweeps of sand, its reefs, its dripping boulders. I admit the comparative inferiority of ponds; but, you see, we are not near the coast, and the heath is close at hand. Nay, if the case were otherwise, I should object to dwarfing comparisons. It argues a pitiful thinness of nature (and the majority in this respect are lean) when present excellence is depreciated because some greater excellence is to be found elsewhere. We are not elsewhere; we must do the best we can with what is here. Because ours is not the Elizabethan age, shall we express no reverence for our great men, but reserve it for Shakspeare, Bacon, and Raleigh, whose traditional renown must overshadow our contemporaries? Not so. To each age its honour. Let us be thankful for all greatness, past or present, and never speak slightingly of noble work, or honest endeavour, because it is not, or we choose to say it is not, equal to something else. No comparisons then, I beg. If I said ponds were finer than rock-pools, you might demur; but I only say ponds are excellent things, let us dabble in them; ponds are rich in wonders, let us enjoy them.
And first we must look to our tackle. It is extremely simple. A landing-net, lined with muslin; a wide-mouthed glass jar, say a foot high and six inches in diameter, but the size optional, with a bit of string tied under the lip, and forming a loop over the top, to serve as a handle which will let the jar swing without spilling the water; a camel-hair brush; a quinine bottle, or any wide-mouthed phial, for worms and tiny animals which you desire to keep separated from the dangers and confusions of the larger jar; and when to these a pocket lens is added, our equipment is complete.
As we emerge upon the common, and tread its springy heather, what a wild wind dashes the hair into our eyes, and the blood into our cheeks! and what a fine sweep of horizon lies before us! The lingering splendours and the beautiful decays of autumn vary the scene, and touch it with a certain pensive charm. The ferns mingle harmoniously their rich browns with the dark green of the furze, now robbed of its golden summer-glory, but still pleasant to the eye, and exquisite to memory. The gaunt windmill on the rising ground is stretching its stiff, starred arms into the silent air: a landmark for the wanderer, a landmark, too, for the wandering mind, since it serves to recall the dim early feelings and sweet broken associations of a childhood when we gazed at it with awe, and listened to the rushing of its mighty arms. Ah! well may the mind with the sweet insistance of sadness linger on those scenes of the irrecoverable past, and try, by lingering there, to feel that it is not wholly lost, wholly irrecoverable, vanished for ever from the Life which, as these decays of autumn and these changing trees too feelingly remind us, is gliding away, leaving our cherished ambitions still unfulfilled, and our deeper affections still but half expressed. The vanishing visions of elapsing life bring with them thoughts which lie too deep for tears; and this windmill recalls such visions by the subtle laws of association. Let us go towards it, and stand once more under its shadow. See the intelligent and tailless sheep-dog which bounds out at our approach, eager and minatory; now his quick eye at once recognizes that we are neither tramps, nor thieves, and he ceases barking to commence a lively interchange of sniffs and amenities with our Pug, who seems also glad of a passing interchange of commonplace remarks. While these dogs travel over each other’s minds, let us sun ourselves upon this bench, and look down on the embrowned valley, with its gipsy encampment,—or abroad on the purple Surrey hills, or the varied-tinted trees of Combe Wood and Richmond Park. There are not many such prospects so near London. But, in spite of the sun, we must not linger here: the wind is much too analytical in its remarks; and, moreover, we came out to hunt.
Here is a pond with a mantling surface of green promise. Dip the jar into the water. Hold it now up to the light, and you will see an immense variety of tiny animals swimming about. Some are large enough to be recognized at once; others require a pocket-lens, unless familiarity has already enabled you to infer the forms you cannot distinctly see. Here ([Fig. 7]) are two larvæ (or grubs) of the common gnat. That large-headed fellow (A) bobbing about with such grotesque movements, is very near the last stage of his metamorphosis; and to-morrow, or the next day, you may see him cast aside this mask (larva means a mask), and emerge a perfect insect. The other (B) is in a much less matured condition, but leads an active predatory life, jerking through the water, and fastening to the stems of weed or sides of the jar by means of the tiny hooks at the end of its tail. The hairy appendage forming the angle is not another tail, but a breathing apparatus.
Fig. 7.
Larvæ of the Gnat in two different stages of development (Magnified).
Fig. 8.
Cyclops
a large antennæ;
b smaller do.;
c egg-sacs (Magnified).
Fig. 9.
Daphnia: a pulsatile sac, or heart;
b eggs;
c digestive tube (Magnified).
Observe, also, those grotesque Entomostraca,[17] popularly called “water-fleas,” although, as you perceive, they have little resemblance in form or manners to our familiar (somewhat too familiar) bedfellows. This ([Fig. 8]) is a Cyclops, with only one eye in the centre of its forehead, and carrying two sacs, filled with eggs, like panniers. You observe he has no legs; or, rather, legs and arms are hoisted up to the head, and become antennæ (or feelers). Here ([Fig. 9]) is a Daphnia, grotesque enough, throwing up his arms in astonished awkwardness, and keeping his legs actively at work inside the shell—as respirators, in fact. Here ([Fig. 10]) is an Eurycercus, less grotesque, and with a much smaller eye. Talking of eyes, there is one of these Entomostraca named Polyphemus, whose head is all eye; and another, named Caligus, who has no head at all. Other paradoxes and wonders are presented by this interesting group of animals;[18] but they all sink into insignificance beside the paradox of the amazonian entomostracon, the Apus—a race which dispenses with masculine services altogether, a race of which there are no males!
Fig. 10.
Eurycercus: a heart;
b eggs; c digestive tube (Magnified).
I well remember the pleasant evening on which I first made the personal acquaintance of this amazing amazon. It was at Munich, and in the house of a celebrated naturalist, in whose garden an agreeable assemblage of poets, professors, and their wives, sauntered in the light of a setting sun, breaking up into groups and têtes-à-têtes, to re-form into larger groups. We had taken coffee under the branching coolness of trees, and were now loitering through the brief interval till supper. Our host had just returned from an expedition of some fifty miles to a particular pond, known to be inhabited by the Apus. He had made this journey because the race, although prolific, is rare, and is not to be found in every spot. For three successive years had he gone to the same pond, in quest of the male: but no male was to be found among thousands of egg-bearing females, some of which he had brought away with him, and was showing us. We were amused to see them swimming about, sometimes on their backs, using their long oars, sometimes floating, but always incessantly agitating the water with their ten pairs of breathing legs; and the ladies, gathered round the jar, were hugely elated at the idea of animals getting rid altogether of the sterner sex—clearly a useless incumbrance in the scheme of things!
The fact that no male Apus has yet been found is not without precedent. Léon Dufour, the celebrated entomologist, declares that he never found the male of the gall insect (Diplolepis gallæ tinctoriæ), though he has examined thousands: they were all females, and bore well-developed eggs on emerging from the gall-nut in which their infancy had passed. In two other species of gall insect—Cynips divisa and Cynips folii—Hartig says he was unable to find a male; and he examined about thirteen thousand. Brogniart never found the male of another entomostracon (Limnadia gigas), nor could Jurine find that of our Polyphemus. These negatives prove, at least, that if the males exist at all, they must be excessively rare, and their services can be dispensed with; a conclusion which becomes acceptable when we learn that bees, moths, plant-lice (Aphides), and our grotesque friend Daphnia ([Fig. 9]) lay eggs which may be reared apart, will develop into females, and these will produce eggs which will in turn produce other females, and so on, generation after generation, although each animal be reared in a vessel apart from all others.
While on this subject, I cannot forbear making a reflection. It must be confessed that our sex cuts but a poor figure in some great families. If the male is in some families grander, fiercer, more splendid, and more highly endowed than the female, this occasional superiority is more than counterbalanced by the still greater inferiority of the sex in other families. The male is often but a contemptible partner, puny in size, insignificant in powers, stinted even of a due allowance of organs. If the peacock and the pheasant swagger in greater splendour, what a pitiful creature is the male falcon—no falconer will look at him. And what is the drone compared with the queen bee, or even with the workers? What figure does the male spider make beside his large and irascible female,—who not unfrequently eats him? Nay, worse than this, what can be said for the male Rotifer, the male Barnacle, the male Lernæa—gentlemen who cannot even boast of a perfect digestive apparatus, sometimes not of a digestive organ at all? Nor is this meagreness confined to the digestive system only. In some cases, as in some male Rotifers, the usual organs of sense and locomotion are wanting;[19] and in a parasitic Lernæa, the degradation is moral as well as physical: the female lives in the gills of a fish, sucking its juices, and the ignoble husband lives as a parasite upon her!
Fig. 11.
Volvox Globator, with eight volvoces enclosed (Magnified).
But this digression is becoming humiliating, and meanwhile our hands are getting benumbed with cold. In spite of that, I hold the jar up to the light, and make a background of my forefingers, to throw into relief some of the transparent animals. Look at those light green crystal spheres sailing along with slow revolving motion, like planets revolving through space, except that their orbits are more eccentric. Each of these spheres is a Volvox globator. Under the microscope it looks like a crystalline sphere, studded with bright green specs, from each of which arise two cilia (hairs), serving as oars to row the animal through the water. The specs are united by a delicate network, which is not always visible, however. Inside this sphere is a fluid, in which several dark-green smaller spheres are seen revolving, as the parent-sphere revolved in the water. Press this Volvox gently under your compressorium, or between the two pieces of glass, and you will see these internal spheres, when duly magnified, disclose themselves as identical with their parent; and inside them, smaller Volvoces are seen. This is one of the many illustrations of Life within Life, of which something was said in the last chapter.
Nor is this all. Those bright green specs which stud the surface, if examined with high powers, will turn out to be not specs, but animals,[20] and as Ehrenberg believes (though the belief is little shared), highly organized animals, possessing a mouth, many stomachs, and an eye. It is right to add that not only are microscopists at variance with Ehrenberg on the supposed organization of these specs, but the majority deny that the Volvox itself is an animal. Von Siebold in Germany, and Professor George Busk and Professor Williamson in England, have argued with so much force against the animal nature of the Volvox, which they call a plant, that in most modern works you will find this opinion adopted. But the latest of the eminent authorities on the subject of Infusoria, in his magnificent work just published, returns to the old idea that the Volvox is an animal after all, although of very simple organization.[21]
The dispute may perhaps excite your surprise. You are perplexed at the idea of a plant (if plant it be) moving about, swimming with all the vigour and dexterity of an animal, and swimming by means of animal organs, the cilia. But this difficulty is one of our own creation. We first employ the word Plant to designate a vast group of objects which have no powers of locomotion, and then ask, with triumph, How can a plant move? But we have only to enlarge our knowledge of plant-life to see that locomotion is not absolutely excluded from it; for many of the simpler plants—Confervæ and Algæ:—can, and do, move spontaneously in the early stages of their existence: they escape from their parents as free swimming rovers, and do not settle into solid and sober respectability till later in life. In their roving condition they are called, improperly enough, “zoospores,”[22] and once gave rise to the opinion that they were animals in infancy, and became degraded into plants as their growth went on. But locomotion is no true mark of animal-nature, neither is fixture to one spot the true mark of plant-nature. Many animals (Polypes, Polyzoa, Barnacles, Mussels, &c.), after passing a vagabond youth, “settle” once and for ever in maturer age, and then become as fixed as plants. Nay, human animals not unfrequently exhibit a somewhat similar metempsychosis, and make up for the fitful capriciousness of wandering youth, by the steady severity of their application to business, when width of waistcoat and smoothness of cranium suggest a sense of their responsibilities.
Whether this loss of locomotion is to be regarded as a retrogression on the part of the plant, or animal, which becomes fixed, may be questioned; but there are curious indications of positive retrogression from a higher standard in the metamorphoses of some animals. Thus the beautiful marine worm, Terebella, which secretes a tube for itself, and lives in it, fixed to the rock, or oyster-shell, has in early life a distinct head, eyes, and feelers; but in growing to maturity, it loses all trace of head, eyes, and even of feelers, unless the beautiful tuft of streaming threads which it waves in the water be considered as replacing the feelers. There are the Barnacles, too, which in the first stage of their existence have three pairs of legs, a very simple single eye, and a mouth furnished with a proboscis. In the second stage they have six pairs of legs, two compound eyes, complex in structure, two feelers, but no mouth. In the third, or final stage, their legs are transformed into prehensile organs, they have recovered a mouth, but have lost their feelers, and their two complex eyes are degraded to a single and very simple eye-spot.
Fig. 12.
Water Beetle and its larva.
But to break up these digressions, let us try a sweep with our net. We skim it along the surface, and draw up a quantity of duckweed, dead leaves, bits of stick, and masses of green thread, of great fineness, called Conferva by botanists. The water runs away, and we turn over the mass. Here is a fine water-beetle, Dytiscus, and a larva of the same beetle, called the “Water-tiger,” from its ferocity ([Fig. 12]). You would hardly suspect that the slim, big-headed, long-tailed Water-tiger would grow into the squat, small-headed, tailless beetle: nor would you imagine that this Water-tiger would be so “high fantastical” as to breathe by his tail. Yet he does both, as you will find if you watch him in your aquarium.
Fig. 13.
Dragon-fly larvæ: A ordinary aspect;
B with the huge nipper-like jaw extended.
Fig. 14.
A Limnæca Stagnalis, or water snail.
B Planorbis.
Fig. 15.
Paludina Vivipara.
Continuing our search, we light upon the fat, sluggish, ungraceful larva of the graceful and brilliant Dragon-fly, the falcon of insects ([Fig. 13]). He is useful for dissection, so pop him in. Among the dead leaves you perceive several small leeches, and flat oval Planariæ, white and brown; and here also is a jelly-like mass, of pale yellow colour, which we know to be a mass of eggs deposited by some shell-fish; and as there are few objects of greater interest than an egg in course of development, we pop the mass in. Here ([Fig. 14]) are two molluscs, Limnæus and Planorbis, one of which is probably the parent of those eggs. And here is one which lays no eggs, but brings forth its young alive: it is the Paludina vivipara ([Fig. 15]), of which we learned some interesting details last month. Scattered over the surface of the net and dead leaves, are little dabs of dirty-looking jelly—some of them, instead of the dirty hue, are almost blood-red. Experience makes me aware that these dirty dabs are certainly Polypes—the Hydra fusca of systematists. I can’t tell how it is I know them, nor how you may know them again. The power of recognition must be acquired by familiarity: and it is because men can’t begin with familiarity, and can’t recognize these Polypes without it, that so few persons really ever see them. But the familiarity may be acquired by a very simple method. Make it a rule to pop every unknown object into your wide-mouthed phial. In the water it will probably at once reveal its nature: if it be a Polype, it will expand its tentacles; if not, you can identify it at leisure on reaching home, by the aid of pictures and descriptions. See, as I drop one of these into the water, it at once assumes the well-known shape of the Polype. And now we will see what these blood-red dabs may be; in spite of their unusual colour, I cannot help suspecting them to be Polypes also. Give me the camel-hair brush. Gently the dab is removed, and transferred to the phial. Shade of Trembley! it is a Polype![23] Is it possible that this discovery leaves you imperturbable, even when I assure you it is of a species hitherto undescribed in text-books? Now, don’t be provokingly indifferent! rouse yourself to a little enthusiasm, and prove that you have something of the naturalist in you by delighting in the detection of a new species. “You didn’t know that it was new?” That explains your calmness. There must be a basis of knowledge before wonder can be felt—wonder being, as Bacon says, “broken knowledge.” Learn, then, that hitherto only three species of fresh-water Polypes have been described: Hydra viridis, Hydra fusca, and Hydra grisea. We have now a fourth to swell the list; we will christen it Hydra rubra, and be as modest in our glory as we can. If any one puts it to us, whether we seriously attach importance to such trivialities as specific distinctions resting solely upon colour, or size, we can look profound, you know, and repudiate the charge. But this is a public and official attitude. In private, we can despise the distinctions established by others, but keep a corner of favouritism for our own.[24]
I remember once showing a bottle containing Polypes to a philosopher, who beheld them with great calmness. They appeared to him as insignificant as so many stems of duckweed; and lest you should be equally indifferent, I will at once inform you that these creatures will interest you as much as any that can be found in ponds, if you take the trouble of studying them. They can be cut into many pieces, and each piece will grow into a perfect Polype; they may be pricked, or irritated, and the irritated spot will bud a young Polype, as a plant buds; they may be turned inside out, and their skin will become a stomach, their stomach a skin. They have acute sensibility to light (towards which they always move), and to the slightest touch; yet not a trace of a nervous tissue is to be found in them. They have powers of motion, and locomotion, yet their muscles are simply a network of large contractile cells. If the water in which they are kept be not very pure, they will be found infested with parasites; and quite recently I have noticed an animal, or vegetal, parasite—I know not which—forming an elegant sort of fringe to the tentacles: clusters of skittle-shaped bodies, too entirely transparent for any structure whatever to be made out, in active agitation, like leaves fluttering on a twig. Some day or other we may have occasion to treat of the Polypes in detail, and to narrate the amusing story of their discovery; but what has already been said will serve to sharpen your attention and awaken some curiosity in them.
Again and again the net sweeps among the weed, or dredges the bottom of the pond, bringing up mud, stones, sticks, with a fish, worms, molluscs, and tritons. The fish we must secure, for it is a stickleback—a pretty and interesting inhabitant of an aquarium, on account of its nest-building propensities. We are surprised at a fish building a nest, and caring for its young, like the tenderest of birds (and there are two other fishes, the Goramy and the Hassar, which have this instinct); but why not a fish, as well as a bird? The cat-fish swims about in company with her young, like a proud hen with her chickens; and the sun-fish hovers for weeks over her eggs, protecting them against danger.
The wind is so piercing, and my fingers are so benumbed, I can scarcely hold the brush. Moreover, continual stooping over the net makes the muscles ache unpleasantly, and suggests that each cast shall be the final one. But somehow I have made this resolution and broken it twenty times: either the cast has been unsuccessful, and one is provoked to try again, or it is so successful that, as l’appétit vient en mangeant, one is seduced again. Very unintelligible this would be to the passers-by, who generally cast contemptuous glances at us, when they find we are not fishing, but are only removing Nothings into a glass jar. One day an Irish labourer stopped and asked me if I were fishing for salmon. I quietly answered, “Yes.” He drew near. I continued turning over the weed, occasionally dropping an invisible thing into the water. At last, a large yellow-bellied Triton was dropped in. He begged to see it; and seeing at the same time how alive the water was with tiny animals, became curious, and asked many questions. I went on with my work; his interest and curiosity increased; his questions multiplied; he volunteered assistance; and remained beside me till I prepared to go away, when he said seriously: “Och! then, and it’s a fine thing to be able to name all God’s creatures.” Contempt had given place to reverence; and so it would be with others, could they check the first rising of scorn at what they do not understand, and patiently learn what even a roadside pond has of Nature’s wonders.