CHAPTER VII.

FOOD AND COMFORT.

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.

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PUTTING aside 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 on great 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.

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IN Nature 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.

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, the liquid 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.

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.

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THE accompanying illustration represents the artificial and natural way of preserving food in an uninjured state. The right-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.

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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.

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THE right-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.

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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.

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 fed that 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.

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.

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BEING on 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 is quite 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.

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WITH regard 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 as _Œstrus 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.

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WE now 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.

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.

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IN Nature 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 slight twig, 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.

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A STILL more 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 discovered that 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.”

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THERE are 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.

USEFUL ARTS.