Image unavailable: TRACHEA OF INSECT, WITH ITS SPIRAL THREAD. TUBE OF GAS-LAMP, WITH ITS SPIRAL WIRE.TRACHEA OF INSECT, WITH ITS SPIRAL THREAD. TUBE OF GAS-LAMP, WITH ITS SPIRAL WIRE.
The large tubes which convey air to divers are made in the same manner, as they would not only succumb to the pressure of the water without the wire, but could not be dragged over obstacles or round corners without collapsing. It often happens that a diver is obliged, when surveying a sunken ship, to traverse the whole of her interior, descending ladder after ladder, and entering every cabin in the ship. This could not be done but for the internal coil of wire within the tube. Reference will presently be made to the subject of diving.
Onthe left hand is seen an object that looks something like a branch hollowed very thin. It is a magnified view of part of the Trachea or breathing-tube through which air is conveyedinto the system of an insect. These breathing-tubes ramify to every portion of the body of an insect, even penetrating to the extremities of the antennæ, the wings, and the legs. It is obvious that as these organs are in tolerably constant movement, and the legs are much bent at every joint by the action of walking, the air-tubes which run through them must possess the same qualities as those of the gas-lamp and diver.
If one of these tracheæ be removed and placed under the microscope, it will be seen to be constructed in a manner exactly similar to that which has been described. Within the membrane which forms the tube proper there is a very fine, but very strong thread, which is coiled exactly like the wire spring. It is not attached to the membrane, and so strong is it that, although it is all but invisible to the naked eye, it can be drawn out as shown in the left-hand figure of the illustration. If laid on a piece of glass, it immediately tries to recoil itself, and for some little time will twist and curl about as if it were alive.
Image unavailable: TRACHEA OF DRAGON-FLY LARVA. TUBE OF HOOKAH.TRACHEA OF DRAGON-FLY LARVA. TUBE OF HOOKAH.
Onthe above illustration are two similar examples of the spiral thread with a flexible tube. The right-hand figure represents one of the many forms of the water-pipe, whether known as Hookah, Narghile, or Hubble-bubble. In the simpler forms of this pipe, such as the latter, the inhaling-tube is quite straight, and the bowl is held in the hands of the smoker. In the more refined pipe, however, the tube is very long, flexible, and made elastic by an inner spiral wire.
Perhaps the reader may remember that the larva of the Dragon-fly is a most remarkable creature in consequence ofits methods of propulsion and respiration. The water is taken into the interior of the body through a peculiarly formed aperture, and then ejected with such violence as to drive the body forward on the same principle as that which causes a rocket to ascend.
The figure on the left hand of the illustration is a representation of the abdomen of this larva rather magnified, and opened so as to show the interior. On either side run the two principal breathing-tubes, through the delicate membranes of which the spiral thread can plainly be seen.
These tubes are connected with a smaller set, and they with a still smaller, so that at last they are of such tenuity that they can scarcely be distinguished without the use of a glass. But, however small they may be, they are always fitted with the spiral thread.
Wenow come to the cases where the membrane is supported by a series of rings, and not by a single spiral wire.
In the right-hand division of the illustration are two specimens of objects which shall be nameless, but which were drawn per special favour at a milliner’s shop. Although the day has now happily gone by when the larger object was in general wear, and seemed to be irrepressively increasing in dimensions, certain modifications of it, under various names, have made their appearance in almost every book of fashions and every large milliner’s shop.
Here we have the external membrane made of linen, calico, merino, or similar material, distended by a number of elastic rings set at tolerably even distances from each other.
The two small objects represent the handy little paper lanterns so common in China and Japan. They are composed of an external coat of tough tissue paper, so thin that it allows the light to pass through it with tolerable freedom, and of an internal series of elastic rings, which not only support it and preserve its cylindrical shape, but allow it to be folded up flat when not wanted.
I possess a singularly ingenious lantern of this kind, made in Japan, and displaying the thoroughness of work which characterizes that nation. It is five inches in diameter, and the lantern itself is affixed at either end to a circular wooden capthe upper fitting over the lower. Consequently, when the lantern is shut, it is entirely enclosed between these two caps, which effectually preserve it from harm. It is delicately finished, and has no less than thirty rings, made of very narrow strips of bamboo. The upper cap has a little trap-door through which the candle can be admitted and trimmed, and in its centre is a small round hole for the passage of air.
Inthe left-hand division of the illustration are shown several examples of ringed and spiral tissues belonging to the vegetable world, in which the principle is exactly the same as that of the Chinese lantern, &c. That on the right hand is an example of simple rings within a membrane. The central figure shows a double spiral, which produces very much the appearance of a series of rings; and on the extreme left is an interesting example which shows the transition in the internal supports from spirals to rings.
Image unavailable: SPIRAL AND RINGED FIBRE (VEGETABLE). NAMELESS OBJECTS. PAPER LANTERNS.SPIRAL AND RINGED FIBRE (VEGETABLE). NAMELESS OBJECTS. PAPER LANTERNS.
I have already mentioned that the proboscis of the House-fly exhibits this modification. If one of these objects be placed under a moderate power microscope—the half-inch isquite enough—and examined, it will be seen that there are some large tracheæ, just like those of the Dragon-fly larva, on each side of the proboscis, and that, where the end is widened and flattened into a sort of disc, their place is taken by a set of very much smaller tracheæ, coming nearly to a point, and each being supported internally by a series of incomplete rings, shaped very much like the letter C. A slide containing this object well mounted can be purchased at any optician’s for a shilling.
Thetrachea, or windpipe, as we call it, of all vertebrate animals, man included, is formed on exactly the same principle, as any one may see by going to a butcher’s shop, and looking at the trachea, or windpipe, by which the lungs, or “lights,” as they are called, are suspended. Were it not for this structure, we should not be able to bend our necks or turn our heads.
Image unavailable: OX. PIG. GOOSE.OX. PIG. GOOSE.
The accompanying illustration shows the tracheæ of three well-known creatures. The left-hand figure is the trachea of an Ox, the central figure that of a Pig, and the right-hand figure that of a Goose. Mr. Tuffen West, who made the drawings, sent with them the following remarks:—
“The tracheæ of animals furnish some very interesting examples of variation in the form and arrangement of the rings. Their purpose, perhaps, one can but guess at in some cases; but doubtless, as being works of the Master Builder, careful study would be repaid.
“In the Ox the rings are very strong and close, and in form like a horse-shoe with the ends approximated.
“In the Pig the incomplete rings are broad at one part, and narrow on the opposite side, with a tendency to spiral arrangement. I imagine that this would make a very rigid tube, and, indeed, it feels so in the hand.
“Then, in the Goose, the narrowed lower part is that which is figured just before the trachea reaches the sternum. The (complete) rings are twice as broad in one half as in the other, and by the alternate disposition of these differing widths, a tube is formed of great flexibility fore and aft, but almost absolutely rigid in the lateral direction. This seems to be so marked an evidence of design as to be calculated to greatly raise our admiration.”
Image unavailable: RINGED TISSUES OF SUGAR-CANE VEGETABLE SPIRAL TISSUES TENDING TO RINGS.RINGED TISSUES OF SUGAR-CANE VEGETABLE SPIRAL TISSUES TENDING TO RINGS.
Wehave seen several examples of ringed tissues tending to the spiral form, and it is but natural that we should expect to find spiral tissues tending to the ring.
In the accompanying illustration the two left-hand figures represent the curiously modified ringed tissue which is to be found in the sugar-cane, the left-hand figure being much more magnified than the other.
The other figures represent four examples of vegetable spiral tissues, in which it will be seen that there is a tendency to form rings, and that if a number of rings were substituted for thespiral, and the object viewed in a slanting direction, it would be almost impossible to distinguish between the ring and the spiral.
Among the most remarkable of these examples are the two right-hand figures. That on the extreme right represents a spiral vessel taken from the so-called root, or “rhizome,” of the Water-lily, and the other is a similar vessel taken from a branch of the Yew-tree. It has been suggested that to this spiral structure is due the proverbial elasticity of the yew-tree, which has from time immemorial rendered it the best wood for the manufacture of bows.
Ithas already been mentioned that the flexible tubes used by modern divers are constructed on the model of several structures belonging to the animal and vegetable kingdoms.
We will now see how they are utilised.
Inthe earlier stages of the diver’s art the Diving-bell afforded the only means of gaining access to the bed of the sea, even in comparatively shallow waters. The mode in which this result was obtained was simple enough, and though it carried with it the germs of still greater improvements, was but limited and uncertain in its action.
The reader is probably aware that if a vessel be filled with air, no liquid can obtain admittance until a corresponding amount of air be set free. Suppose, for example, that an empty tumbler be inserted over a basin of very clean water, and pressed downwards, it will be found that scarcely any water will enter it, the air having taken up all the available space, and only allowing as much space as may be accounted for by its faculty of compression.
It is evident, therefore, that if an enlarged tumbler could be lowered to the bed of the sea, a man might be enclosed within it, and for a time be able to support life by means of the air contained within the “bell,” as this enlarged tumbler was popularly called.
It is equally evident that within a short time the air within the bell must be exhausted, and that, unless a fresh supplycould be introduced, the diver within the bell would be as effectively drowned as if there were no bell at all.
The accompanying illustration is a kind of chart, so to speak, of the mode in which air was formerly supplied to the bell.
On the right hand is seen a section of the Diving-bell itself, together with the seat on which the divers can rest. There is also an escape-valve at the top of the bell, by which the vitiated air can pass away; but, as it is not essential to the subject in hand, and is rather complicated in structure, it has been omitted.
Immediately on the left of the bell is a cask, to which several heavy weights are attached. This cask contained compressed air, and, after it was lowered by the side of the bell, the end of the flexible tube was taken into the bell, the tap turned, and the compressed air rushed into the bell, taking the place of that which had been exhausted by respiration, and was allowed to pass through the escape-valve. I may mention that the divers unexpectedly discovered that, when they were breathing compressed air, they could dispense with respiration for a wonderfully long time, the amount of oxygen taken in at a single breath being enough to renovate the blood more than could be done by several ordinary inspirations.
Image unavailable: NEST OF WATER-SPIDERS. DIVING-BELL.NEST OF WATER-SPIDERS. DIVING-BELL.
On the left hand of the illustration is seen a sketch of the nest of the now familiar Water-spider (Argyronetra aquatica), taken from some specimens in my possession.
The Water-spider is really a remarkable being. Itself a denizen of air, breathing our earthly atmosphere just as we do, and as capable of being drowned as ourselves, it nevertheless passes nearly the whole of its existence under water, and in that strange locality lays its eggs and rears its young. How this wonderful feat is performed we shall now see.
When the female Water-spider wishes to deposit her eggs, she looks out for a suitable locality, and, being a good diver, tests the various aquatic herbage until she has found a favourable spot, and then sets to work on her remarkable nest, which I believe is quite original in zoology.
After stretching a few stout threads by way of a scaffolding, she attaches to the plant a small silken cell, shaped very much like an acorn, but not so large. Ascending to the surface of the water, she contrives to clasp a bubble of air between her last pair of legs, and, laden with this airy treasure, dives below.
As soon as she has reached the entrance to the cell, which is always below, she loosens her hold of the air-bubble. It at once rises into the cell, and expels a proportionate amount of water. Not many of these journeys are required before the nest is filled with air, and then the diminutive architect spends the greater part of its time in holding on to the mouth of the little diving-bell, and supporting life by means of the air within it.
This nest, as the reader will see, is an exact representation of the various diving schemes in which air-bells are the chief portions of the machinery, although the air is conducted into them after a different fashion.
Wenow come to another mode of diving, in which the bell is practically superseded by the flexible tube, which allows to the diver far more range than can be obtained by the bell. In this case the diver wears a peculiar dress, the chief part of which is a helmet so constructed that air can be introduced to it from above the surface of the water, and, after respiration, can escape by means of a valve.
Air is pumped into the tube by assistants above water, and, as the tube is long and elastic, the diver can move about with considerable freedom. As is the case with the diving-bell, the diver’s tube is strengthened by an internal spiral wire, so that it is always open, however it may be bent or twisted.
The right-hand figure of the illustration represents the diver examining part of a sunken vessel. The tube through which he breathes is seen passing to the surface of the water, and so is the line by which he gives his signals to his comrades above. In his hand he holds a lamp which can burn for a limited time, being connected by a smaller but similarly constructed tube to a vessel of compressed air.
Onthe left hand of the same illustration are shown the curious Rat-tail Maggots, as they are popularly called. They are the larvæ of the common Drone-fly (Eristalis tenax), which is so common towards the end of summer, and looks so curiously like a bee.
Image unavailable: RAT-TAILED MAGGOTS. DIVER WITH AIR-TUBE.RAT-TAILED MAGGOTS. DIVER WITH AIR-TUBE.
These creatures pass their larval life buried in the mud and below the surface of the water, and yet are obliged to breathe atmospheric air. This they do by means of the long appendages which have gained for them the name of Rat-tails. These “tails” are very elastic, and are capable of elongation and contraction to a wonderful extent.
When the creature is undisturbed, it lies buried in the mud with its head downwards, and its tail extended so that it reaches the surface of the water. Within this tail are two air-tubes, which are connected with the principal tracheæ, whichhave already been mentioned. They are wonderfully elastic, and, when the tail is extended to its utmost limit, are nearly straight. When, however, the tail is contracted, the tubes become self-coiled by their own elasticity, and shrink into the base of the tail.
As the tail is very transparent, it is easy to see how these movements are conducted. The larvæ, which may be found in almost any stagnant water, should be placed in a tall and narrow glass. Some mud should be placed at the bottom of the glass, which should then be filled with water to the depth of three inches or so.
When the mud has quite subsided, and the water become clear, the long slender tails of the larvæ will be seen so elongated that their tips reach just above the surface of the water. A magnifying-glass will easily show the two tubes within the tail.
Let the glass be but slightly tapped, and all the tail is withdrawn in a moment, so as to be out of reach of external danger. The magnifying-glass will then show the two tubes lying contracted in the base of the tail, and taking astonishingly little space, considering the amount of elongation which they can sustain. And, on examining the various bends and curves of the tubes, the value and power of the spiral spring will at once be seen. True, they are very small, but in Nature all things go by comparison, and our whole earth itself is as a grain of sand upon the seashore among the grandeurs of the visible universe.
Thelast of the springs which can be mentioned in this work are those which are used for leaping purposes.
The figure on the right hand represents the common Spring-jack or Skip-jack with which children are always so much amused. It consists of a flattened piece of wood called the “tongue,” which is inserted into a twisted string, so that it forms a tolerably powerful spring. When twisted round, and then suddenly released, it strikes against the ground with such force that the whole machine is thrown into the air.
Sometimes the Skip-jack is made of a fowl’s merrythought, asshown in the illustration; sometimes of the breast-bone of a goose; and sometimes of a piece of wood cut into the semblance of a frog, and painted. In all cases, however, the machinery is practically the same. I may mentionen passantthat these frog Skip-jacks are most acceptable presents to savage chiefs in many parts of the world, and that the most powerful and venerable warriors are as delighted with these toys as any European child of six years old.
Nowwe will turn to Nature, and see what she has in the way of Skip-jacks.
All entomologists will at once have before their minds the vast groups of Skip-jack Beetles, technically termedElateridæ, and also known as Click-beetles, from the sharp clicking sound which they produce when in the execution of their curious gymnastics. To this group belong the fire-flies of warm countries, and it may be mentioned that the larvæ of some of our species are too familiar to the agriculturist under the name “wireworm.”
Image unavailable: SKIP-JACK BEETLE. GRASSHOPPER. SKIP-JACK.SKIP-JACK BEETLE. GRASSHOPPER. SKIP-JACK.
All these beetles have very short legs and very long bodies, so that if they should fall on their backs on a smooth surface, they could not recover themselves. Now, as they, when discovered, instinctively try to save themselves by falling to the ground, it is evident that some means must be used to enable them to regain their position. This is found in a most curious apparatus.
Attached to the “prothorax” is a rather long, pointed, and very elastic projection exactly corresponding with the tongueof the Skip-jack. The end of this tongue fits into a groove in the “sternum.”
When the beetle falls on its back, it curves its body as shown in the illustration, the tongue thus being freed from its groove. It then smartly springs the tongue back into its place with the sharp clicking sound already referred to, and does so with such force that it leaps into the air to some height.
Generally it falls on its feet, but if it should fail, it repeats the process. If one of these beetles be laid on a plate or similar smooth surface, it will skip ten or twelve times without stopping, and after a short rest will begin again.
Thereare some curious little beings, popularly called Spring-tails, which afford excellent examples of the Leaping Spring. Their exact place in the system of Nature is rather uncertain, some zoologists considering them as insects, while strict entomologists reject them. They are very small, and mostly of a darkish brown colour.
Plenty of them may be found under stones in damp spots, under bark, and in similar localities, though they are often found in houses, and have frequently traversed the paper on which I have been writing this book. Cellars are favourite localities of theirs, and a little flour sprinkled on a plate or piece of paper in a cellar is tolerably sure to attract them. Although they are certainly not more than the fifteenth of an inch in length, they may be at once recognised by their peculiar attitude, which very much resembles that of a dog or cat in its usual sitting posture.
As long as they are not disturbed they crawl about in a quiet manner, but if touched, or even alarmed, they suddenly make a tremendous leap, propelling themselves by means of a forked and elastic tail, doubled under their bodies, and acting just like the tongue of a Skip-jack.
Belowthe Skip-jack Beetle is shown the common Grasshopper, as an example of muscular leaping springs.
We all know what wonderful leaps the Grasshopper, Cricket, and all their kin can make, the leaping movement being evidently intended more as a means of defence than as an ordinary mode of locomotion. The same may be observed inthe Kangaroos and Gerboas, which are content to use an ordinary walking pace when undisturbed, but when alarmed can make tremendous leaps, and outstrip almost any pursuer.
Even in Man, the Horse, the Dog, &c., which are most essentially leaping animals, the same principle is employed, the legs being used as muscular springs acted upon by the will of the owner.
Parents and their Young.—Milk, and the various Ways of obtaining and using it.—The Kafir Tribes and Clotted Milk.—The Tonga Islanders.—The Tartars.—Ants and Aphides.—Honey-dew.—Milch Cows in Insect-land.—Fish-tanks and Aquaria.—Bill of the Pelican.—Eggs and Chickens.—The Hen-coop.—Nest of Termite.—Workers and Queen.—Egg-hatching.—The Hen and her Young.—Artificial Egg-hatching Machine.—The Snake and her Eggs.—The Gad-fly and Bot-fly.—Preservation of Provisions.—Hanging Meat.—Eggs of the Lace-wing Fly.—Spider-eggs.—The Butcher’s Hook and the Claws of the Sloth.—Bats and Insects.
Parents and their Young.—Milk, and the various Ways of obtaining and using it.—The Kafir Tribes and Clotted Milk.—The Tonga Islanders.—The Tartars.—Ants and Aphides.—Honey-dew.—Milch Cows in Insect-land.—Fish-tanks and Aquaria.—Bill of the Pelican.—Eggs and Chickens.—The Hen-coop.—Nest of Termite.—Workers and Queen.—Egg-hatching.—The Hen and her Young.—Artificial Egg-hatching Machine.—The Snake and her Eggs.—The Gad-fly and Bot-fly.—Preservation of Provisions.—Hanging Meat.—Eggs of the Lace-wing Fly.—Spider-eggs.—The Butcher’s Hook and the Claws of the Sloth.—Bats and Insects.
THIS subject is necessarily a very large one, and I shall, in consequence, be obliged to compress it, though it might well make a separate work by itself. For Food represents the very existence of Man, considered as one of the animal world; and Comfort represents the progress of civilisation, by which man leaves day by day his savage and solitary nature behind him, and becomes social, moral, and elevated.
Puttingaside the instinct which forces the parent to feed the young without external assistance, we come to those cases where the parent has to seek food which the offspring could not have found for itself, and often to prepare it for the use of the offspring.
In the greater part of the world, the milk of various animals is the staple of food, not only for children, but adults; and the “milk diet,” as it is called, is strongly urged by many physicians of the present day.
The Kafir tribes, for example, a wonderfully powerful race of men, live almost wholly on sour milk, mixed with maize flour, never eating such valuable animals as kine except ongreat occasions. Yet the natives of the Tonga Islands think that nothing can be more disgusting than for a human being to drink the milk of a cow.
How the operation of milking is conducted we need not say, whether it be performed on the cow as with most nations, or the ass in case of need with ourselves, or the mare as with the Tartars, or the goat and sheep in various parts of the world. The milk of the sheep, by the way, is singularly rich and nourishing.
Suffice it to say that the animals which are to be milked are kept for that purpose, and that the touch of the human hand, rightly applied, induces the animal to part with its milky stores.
InNature there is an exact parallel.
It has long been known that some species of Ants are in the habit of acting in exactly the same manner as ourselves, in not only extracting a nutritious liquid from other insects, but watching and tending those which furnish their daily food just as a good dairyman watches and tends his cows.
Image unavailable: ANT AND APHIS. MILKING COW.ANT AND APHIS. MILKING COW.
The Ants, being insects, would naturally require insect cows, and such are to be found in the Aphides, of which mention has already been made. These insects are furnished with a pair of very small tubercles near the end of the abdomen, and from them flows that sweet liquid which is so familiar to us under the name of “honey-dew.” For centuries no one knew the source of the sweet honey-dew which attracted all the bees of the neighbourhood to the tree on whose leaves it was sprinkled, sometimes in patches, and sometimes coating them with a thin shining coat, as if varnished.
At last it was discovered that the honey-dew is, in fact, theliquid exudations from these tubercles upon the backs of the aphides, and that the ants feed regularly upon it. Not only do they lick up the honey-dew that has fallen from the ants, but they milk them, so to speak, exactly as a dairymaid milks a cow. With their antennæ the ants pat and stroke the tubercles of the aphides, and in a few seconds a drop of pellucid liquid appears at the extremity. This is the honey-dew, and is at once lapped up by the ant, which proceeds from one aphis to another until it has obtained its fill of the sweet food.
How the ants carry off the aphides, cherish and guard them for the sake of their honey-dew, is a story too long to be told, but it is well known among entomologists. Our English ants are, however, totally eclipsed by a Mexican species, which not only collects honey, but stores it in the bodies of its kindred.
Image unavailable: PELICAN. FISH-TANK.PELICAN. FISH-TANK.
After taking precautions that no food can escape, the ants feed with their sweet store their companion, who is thus doomed to pass the remainder of life as a mere honey-cell. The abdomen becomes spherical, smooth, and so transparent that the honey can be seen within it. It is quite air-tight, and so preserves the fragrance of the honey until it is wanted.
So plentiful are these honey-ants, that they are an article of commerce, and are sold by measure for the purpose of making a sort of mead. There are many of them in the British Museum, with the honey still within their transparent bodies, and they are well worth seeing.
Theaccompanying illustration represents the artificial and natural way of preserving food in an uninjured state. Theright-hand figure is that of an ordinary glass aquarium, such as was in general use until the properties of air and water were better understood, and it still need not be rejected. It is simply a vessel in which water is contained, so that aquatic or marine animals may be able to live in it for some time.
There are infinite varieties of the “Fish-tank,” if we may so call it, the chief of which is the “well,” which is so extensively used in bringing fish to market.
Through the bottom of the boat projects a sort of box pierced with holes, so that the water has free access and egress. The sides of the box are so high that there is no fear of the water rising into the boat. When fish are taken, they are thrown into the well, and there can live until they are wanted for sale.
Also, as all know who are acquainted with river-banks or seashores, fishermen have similar wells detached from the boats, and partly or entirely sunk in the water. In them they keep their stock, and, when a customer arrives, they simply draw the box ashore, so that the water runs out, select what fish they choose, and replace the box in the water.
Now, the power of conveying fish to some distance without destroying life has for countless ages been possessed by the Pelican, one of which birds is shown in the accompanying illustration.
As every one knows, the chief peculiarity of this bird is the large and very elastic membrane of the lower jaw. When not in use, it contracts by its own elasticity, and the bill looks quite slender, as well as long. But, when distended with water and fish, it presents the appearance shown in the illustration.
Any one who wishes to see the exercise of this power can do so by attending the Zoological Gardens, and visiting the Pelicans at feeding-time, and an hour or two before it. They hardly seem to be the same birds. Some years ago I made a series of sketches of the same Pelican under different circumstances, and it is scarcely possible to believe that they could be, as they are, truthful representations of the same bird.
Theright-hand figure of the next illustration requires no comment, as it simply represents the ordinary hen-coop.
As everybody is aware, the object of the coop is to keep the hen within its bars, while the little chicks can run in and out as they choose, and the coop is made so as to prevent the egress of the mother, while the offspring find no difficulty in escaping.
Now, in the world of insects we find an exactly analogous structure. As is the case with many hymenopterous insects, there is in the nest of the Termite, or White Ant, as it is popularly called, a single perfect female, which is the mother of the nest. A similar arrangement occurs in the common hive-bee, but there is a notable distinction between the queen Bee and the queen Termite, the latter belonging to the neuropterous order.
Image unavailable: QUEEN TERMITE IN HER CELL. HEN IN HER COOP.QUEEN TERMITE IN HER CELL. HEN IN HER COOP.
The former is unconfined, and moves about from cell to cell, depositing her eggs within them, and taking the greatest pains that they occupy exactly their proper place within the cell. The latter never moves after she has begun to deposit eggs, but remains motionless in the same spot, and allows her subordinates to dispose of the eggs which she lays.
How this end is achieved will now be seen.
The reader is probably aware that the queen Termite attains to enormous dimensions, her head, thorax, and legs retaining their normal size, but the abdomen becoming several inches in length, and thick in proportion. The legs are necessarily unable to move so vast a body, and in order that so important a personage should not receive injury, a large oval cell is built around her, from which she never moves for the rest of her life. She has but one duty, namely, to lay eggs, and so is fedthat she may have strength to produce them. She is simply passive, and never even sees her eggs, much less has care of her young.
All the care of guarding and nurturing the eggs and young falls upon the worker Termites. These insects are quite small, about the size of our common Wood-ant.
When they build the clay cell around their queen, they bore a number of holes along the sides, which are just large enough to allow the workers to pass freely, but which effectually exclude the soldier Termites, or any foes larger than themselves.
Through these apertures streams of workers are continually passing—some entering the cell to fetch the eggs, and others coming out with eggs carried carefully in their jaws.
Image unavailable: “WURBLES” OF ŒSTRUS. EGG-HATCHING MACHINE.“WURBLES” OF ŒSTRUS. EGG-HATCHING MACHINE.
Thus, as the reader will see, we have in Nature an exact analogy of Art, the Termite queen being confined within her cell exactly as is the hen within the coop.
Beingon the subject of eggs and egg-hatching, we will take another case in which Art has acknowledgedly followed Nature.
We all know that eggs are developed into life by means of well-regulated heat, and that with birds the general rule is, that the needful heat is supplied by the parent bird, who sits upon them for a certain time, until the young birds make their appearance in the world.
Under ordinary circumstances, the aid of the parent bird isquite sufficient; but when the progress of civilisation requires that the eggs of poultry should be hatched in numbers too great for the powers of the parent bird, Man has been fain to imitate Nature, and to invent machines whereby eggs can be hatched by artificial heat, regulated to the temperature of the hen’s body.
Various as are these machines in detail, they are all alike in principle, and the right-hand figure of the accompanying illustration will give a fair idea of the method which is employed.
A box is fitted up with trays, on which the eggs are arranged. At the bottom of the box there is the heat-producing apparatus, which can be regulated at pleasure. The trays of eggs can be moved from one part of the box to another, so as to insure the right amount of heat, and, if this process be only carefully carried out, the young chicks emerge from the eggs exactly as they would have done if the hen had sat upon them.
This machine is sometimes called the Artificial Mother, and it is worthy of notice that it is no modern invention, the ancient Egyptians having used it more than three thousand years ago.
Withregard to Nature, it would have been simple enough to give one illustration of a bird sitting on her eggs, but I have preferred to select a different subject, as more relevant to the question of artificial heat.
There is an insect to which we have had several occasions of reference, namely, the Wurble-fly of the ox, scientifically known asŒstrus bovis.
The eggs of this insect are deposited in the skin of the ox, and are there hatched by the heat of the animal. In proportion as the larva grows, it raises lumps upon the skin, these being practically the roofs of the artificial home. There are several other species of the same genus, all of which have their eggs hatched by the heat of the animals on which they are placed. There are, for example, the common Bot-fly (Œstrus equi), whose eggs are hatched in the interior of the horse, and the Sheep-fly (Œstrus ovis), whose eggs are hatched in the head of the sheep. The common Snake leaves her eggs to be hatched in the artificial heat produced by decaying vegetable matter.
Wenow come to the preservation of provisions.
In the first place, we have the well-known “cache” of Northern America—i.e.a spot wherein provisions are hidden, and their locality only marked by signs intelligible to those for whose use they are intended. It is, perhaps, hardly necessary to mention that many creatures—such as the dog, the squirrel, and most of the crow tribe—are in the habit of concealing provisions for future use.
Image unavailable: SPIDER-NESTS. EGGS OF LACE-WING FLY. SPIDER-NEST. PROVISIONS HUNG TO TREE BRANCH.SPIDER-NESTS. EGGS OF LACE-WING FLY. SPIDER-NEST. PROVISIONS HUNG TO TREE BRANCH.
In those parts of the world, however, where the rights of hunters are acknowledged, any one who kills a deer, or other animal of chase, and is not able to carry off the entire body, can preserve it for his own use. He simply cuts it up in hunter fashion, and hangs the various portions to branches of trees, where they are out of the reach of wild beasts. Stores like these, such as are shown in the illustration, are always respected, and no hunter would dream of helping himself to the game which was killed and dressed by another.
Beasts of prey, however, cannot be expected to be so punctilious, and in consequence the hunters hang their meat to branches which cannot be reached.
InNature we find many similar examples, one or two of which are given on the left hand of the illustration.
In the centre is seen a group of eggs of the Lace-wing Fly (Hemerobius), so called on account of the delicate, lace-like structure of its beautiful pale green wings.
When the female lays her eggs she always chooses a slighttwig, and upon it deposits a little drop of a slimy consistence. She then draws out this drop into a thread, which hardens as it is brought into contact with the air. At the extreme end of the thread she places an egg, which is thus kept at some height above the ground, and defies the approach of inimical insects. The eggs, as well as the stalks, are perfectly white, and have so singular a resemblance to mosses, that for many years they were actually classed and figured as such.
These egg-groups are plentiful enough, if the observer only knows where to look for them. I have several of them in my collection, and have found that nearly every one who sees them for the first time takes them for mosses. I never myself saw the pretty insect lay its eggs, and for the description am indebted to Mr. A. G. Butler, of the British Museum, who has kept them and watched their habits.
The objects on either side of the Lace-wing Fly’s eggs are egg-groups of certain spiders, suspended by threads from branches.
A stillmore remarkable instance of unconscious imitation may be found in the two objects in the accompanying illustration. It is hardly necessary to say that the right-hand figure represents a portion of the arrangement by which a butcher hangs up his meat out of harm’s way until it is wanted.
The hooks in question are simply formed into a double curve, like the letter S, and can be slid along the horizontal bar without any danger of falling.
Now, in the common Sloth we have an exact prototype of the butcher’s hook. The Sloth passes the whole of its life in the remarkable attitude which is shown in the illustration. It lives among the branches—not on them, but under them—its claws being long and curved, just like a butcher’s hook. I have often watched the animal traversing the branches, and have been greatly struck with the accurately picturesque description of the late Mr. Waterton, who was the first to discover the real character of the Sloth.
It was he who found out that the previous ideas as to the Sloth’s mode of life were utterly erroneous, and that, instead of being a sort of bungle, the Sloth was as perfect in its way, and as well fitted for its mode of life, as the lion or tiger. He discoveredthat the animal always hung from the branches, as shown in the illustration. In fact, as Sydney Smith remarked in his witty review of “Waterton’s Wanderings,” the Sloth passes his whole life in suspense, “like a young clergyman distantly related to a bishop.”
Image unavailable: SLOTH. BUTCHERS’ HOOKS.SLOTH. BUTCHERS’ HOOKS.
Thereare many other creatures which afford similar examples, though perhaps none are so striking as the Sloth.
For instance, there are the whole tribe of Bats, which, by means of the curved claws attached to their hind-feet, can hang themselves head downwards in the open air, and even swing in wind, without the least fear of falling.