CHAPTER II.
LOW LIFE.
Some persons go to the seaside every year for several weeks, and yet know little of its treasures. Take away the bands, the bathing machines, the itinerant entertainers of various kinds, the bustling crowds that pass and repass on the grand parade, and they are lonely, miserable, with nothing to occupy their minds. Of the illimitable sea, the cliffs, the sands, the passing sails they soon tire. For a very small sum, as money is considered to-day, such a person could acquire a tolerable microscope, and a very little application to books would put him in the way of getting an absolutely endless fund of interest, knowledge, even amusement from it. Through the magic glasses he enters another world; or, rather they enable him to see that other half of Creation with which he has been rubbing shoulders all his life, yet without seeing the creatures. With such an instrument and the knowledge how to use it, a man may defy the demon ennui wherever he may be. With such an instrument at home a person who is not a naturalist may be induced to look into a rock-pool, to take samples of its fauna and flora, and by and by to become a naturalist without intending or knowing it.
Behold how easy a thing it is! He has but to take away a phial full of the water, a tiny bunch of coralline, the finer green weed, or a snippet of sponge from the walls of the pool, and he has abundance of material whose marvellous beauties of form and colour will delight and astonish him when he has had time to examine it under the microscope. For the coralline tuft and the lowly weed, when washed out in the sea-water, will yield him multitudes of Infusoria, Rhizopoda, and the infantile stages of many of the higher groups of life.
The Foraminifera are the minute creatures which have so largely contributed to the formation of the enormous beds of chalk we find in Surrey, Kent, Sussex, and other counties, such as the explorations of the Challenger showed us are being formed in the deep sea at the present time. So minute are they that one hundred and fifty of them placed side by side would not measure more than one inch, and of such insignificant creatures the chalk is almost entirely composed. What are they? How are they fashioned? How do they live? These questions probably occur to the reader, and I must do my best to briefly answer them.
There is a minute creature, plentiful in ditches and similar accumulations of stagnant water into which decaying vegetation has fallen. It is a minute speck of animated jelly, without form, substance, or limbs. There is, in fact, no closer analogy than the speck of almost clear jelly, to which in some mysterious way life has been given. In the words of the late Dr. W. B. Carpenter, who made a special study of these creatures: “A little particle of homogeneous jelly[1] arranging itself into a greater variety of forms than the fabled Proteus, laying hold of its food without members, swallowing it without a mouth, digesting it without a stomach, appropriating its nutritious material without absorbent vessels or a circulating system, moving from place to place without muscles, feeling without nerves, propagating itself without genital apparatus, and not only this, but in many instances forming shelly coverings for symmetry and complexity not surpassed by those of any testaceous animal.”
[1] It is now known that this jelly-like material is not of so simple a character as was supposed a few years since: the most modern microscopes prove it to be not devoid of structure.
With the exception of the last three-and-twenty words the above description refers to the Amæba and its allies; but in the Foraminifera we have a sort of advanced type of amæbæ, a more æsthetic race that have taken to build themselves houses, in most cases of graceful form, such as are referred to in Dr. Carpenter’s concluding words. One of the fresh-water amæbæ is named Difflugia, and it distinguishes itself by coating the greater part of its small body with particles of sand and other matter picked up as the Difflugia rolls along. The Foraminifera do not resort to so clumsy a method of satisfying their architectural instincts. In the course of their feeding they take into their primitive systems a good deal of carbonate of lime, and instead of casting this out as innutritious, useless stuff, they secrete it as shell, in many cases not unlike the shells of mollusks, but with minute pores (foramina) all over them. From this character they derived their name Foraminifera or pore-bearers.
1. Polymorphina. 2. Textularia. 3. Cristellaria.
Within these perforated shells live the amæba-like animals, and through all these minute pores they protrude still more minute threads or wisps of their living jelly to use as limbs wherewith to pull themselves along, and to catch their food. There is a very ancient conundrum which asks: “What is smaller than a mite’s mouth?” a mite being formerly considered to be the least of all animals and a very minute thing indeed; therefore, to imagine the mouth of a mite was to conceive of something so very small as to be almost beyond conception. But then came the answer: “That which goes into it!” Of course, if a mite had a mouth it must have it for the purpose of eating, so that though nothing were known smaller than a mite, yet a mite must have a mouth, and that could scarcely be quite as large as the mite, and its food must be smaller than its mouth. A naturalist would say that this line of reasoning is weak, and it undoubtedly is so, for there are creatures that contrive to swallow things that are much larger than their mouths; but there is no occasion to split hairs just now. These Foraminifera are in some cases invisible to the unassisted vision, but as each is pierced with many pores, it follows that the individual pore must be almost inconceivably small, though still smaller are the wisps of jelly that protrude through them and invest the outside of the shell. For it must not be supposed that these structures are secreted like the shell of the snail, that the animal may live within it; rather it is like our own skeleton, built up within our bodies.
Some of these shells have but one chamber, like Lagena, which is flask-shaped, and Entosolenia, in which the long neck of the flask has been pushed down inside the globose portion. Others have many compartments, but these are subject to great variety of arrangement, each species having its own special form. Dentalina has the chambers placed one behind the other in a straight or curved line. In Nonionina, Polystomella, Rotalina, Globigerina, and others they are rolled in a spiral, and resemble the chambered shell of the Nautilus; or they may be twined, not spirally, round an axis, each making a half-turn.
In some respects similar to the Foraminifera are the Polycistina, which are equally minute creatures, whose skeletons are of flint instead of chalk, and the perforations are so large and so close together that the term pore no longer adequately expresses their proportionate size. They are more like windows, but with little intervening stonework. The jelly-substance, called sarcode, flows out through all these windows in the form of threads (called pseudopodia or false feet) as in the Foraminifera, spreading over the outer surface and acting as legs and arms by means of which the creature moves and captures its food. They feed upon infusoria of various kinds, and the diatoms and desmids, which appear to be paralysed by contact with the pseudopodia. They also seem to derive part of their nutriment from the exertions of some minute yellow-bodies, a species of algæ (Xanthellæ) that are lodgers within their substance. These lowly plants, which have sometimes been incorrectly alluded to as parasites, elaborate starchy products by the aid of their chlorophyll, and on their death this material is available for the nutrition of the Polycistin, which also can make use of the oxygen given off by the plant.
There is one of these low forms of life in which almost all visitors to the sea-shore take an interest—or rather they are interested in certain signs of its vital activity—the mysterious phosphorescence of the sea. There is no moon visible, the sea is quiet, and our reader late in the evening takes a stroll along the edge of the waves, “before turning in.” He is charmed to see the ripples as they break upon the shore brightly outlined with glow-worm light, and stays long to enjoy the elfish illumination. Now my advice is, do not stay long, but hasten back to your “diggings” and get a bottle; then return and fill it with sea-water at a spot where the phosphorescence is most abundant. You can then examine the creature that produces the strange light.
If now you continue your stroll along to that part of the sea-wall where the male villagers most chiefly congregate to spin yarns with a more or less saline flavour, and to discuss village politics, you will probably hear them talking about fishing prospects, and if it is in early summer, mackerel will be in their talk. “Well,” says one, “there’s no doubt the fish are about, and I propose that we get the sean-boats ready, and to-morrow night we’ll try the briming.” The meaning of which dark saying is that to-morrow evening they will row across the bay till they come under the shadow of the great headland, and there they will adapt the focus of their eyes to seeing below the surface of the crystal waters, and watching for the streaks of phosphorescent light that break from the fins and tails and scales of the mackerel as they pass through the sea. This light is the “briming” of the fishermen. It is due to the movement of the fish exciting the light-producer, just as in a marine aquarium in a dark room you can produce a similar effect by blowing the surface of the water into ripples. The six long oars of the big sean-boat every time they dip into the water send a spray of light into the air, and as they again leave it a shower of glowing pearls drops from each. The prow of the boat sends up a fountain of pale heatless fire on either side, and an ever-widening track of the same mysterious light marks the way the boat has come.
All these brilliant effects are produced by millions of a tiny Infusorian, individually so small that twenty of the finest specimens, placed closely together in Indian file, would only produce a procession one inch in length, whilst of mediocre examples it would require from fifty to eighty to cover the same space. Its size may be insignificant, but it has a name which will at least inspire respect with some persons—Noctiluca miliaris—which may be Englished as the Sea Night-light. If now we go together to your lodgings and examine that bottle of sea-water with a lens we shall be able to make out a large number of these creatures swimming about, and by means of a pipette or dipping tube we can isolate a specimen and place it under the microscope. There it is revealed to us as a peach-shaped individual, the spherical mass being partly mapped into two lobes by the slight groove that, as in the peach, runs down from the depression in which the stalk is attached. The stalk in this microscopic night-light is represented by a long flexible tentacle, or flagellum, by means of which Noctiluca moves through the waters, much as a fisherman will propel his boat by the skilful use of a single paddle at the stern. There is a shell-like envelope of transparent material through which may be seen a meshwork of granular material, denser than the body-mass. A funnel, opening near the flagellum, becomes lost in this granular matter; this is the creature’s mouth and gullet, within which lies a smaller flagellum. The gullet simply opens into the central protoplasm; no continuing alimentary canal has yet been made out. Reproduction is effected by several methods: one is the division of the creature transversely into two, each complete, but for the time smaller; a second method is the conjugation of two individuals and the subsequent breaking up of the protoplasm into numerous spores, each provided with a flagellum. But this breaking up process may occur independently of conjugation. The spores move by the lashing of the flagellum, and gradually develop into the adult form. The light is produced in flashes just under the clear cell wall, and pure sea-water, rich in oxygen, is necessary for its continued brilliancy. At times, on summer evenings, Noctiluca is extremely abundant in the littoral zone, and it is then impossible to take up a glass of water without getting thousands of specimens.
If you occasionally indulge in boating, many forms of low life, or the larval condition of higher forms may be obtained without difficulty. Take a piece of thin, round cane—about the thickness used in training a child in the way he should go—and bend it into a hoop. The two ends should be cut half through for an inch of their length, so that their flat surfaces can be brought together and secured by several turns of a piece of thin copper wire. Now to this cane secure a small flat piece of lead, so that when thrown into the water the hoop will assume an erect position. If you should have a couple of inches of “compo” gas-tubing handy, this will do admirably, and may be slipped over the cane before the ends are lashed together. Upon the hoop now stitch a muslin bag to serve as a net; and to three or four equi-distant points on the frame attach short, strong strings of equal length, and join their ends to a length (say three fathoms) of fishing line. This may be made fast to one of the thwarts of the boat, or held in the hand, whilst the net is thrown overboard. The movement of the boat will cause the net to collect a large number of minute creatures that float on the surface or immediately below it. From time to time it should be hauled in, and the bag turned inside out and washed in a glass jar of sea-water. In this way many interesting forms may be secured. A calm, sunny afternoon should be selected for this work, and the boat should be rowed gently.