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It is used in Egypt by the sailors, whilst attached to the two under chaps, for holding or bailing water. Why was the pelican formerly thought to feed her young with her blood?

Because, in disgorging the food from the pouch for the young, the bird presses the bottom of the sack upon her breast, and thus the contents are discharged.*

THE CORMORANT.

Why has the cormorant a small sabre-shaped bone at the back of its vertex?

Because this bone may serve as a lever in throwing back the head, when the animal tosses the fishes which it has taken into the air, and catches them in its open mouth. This conjecture is by Blumenbach, who, however, observes, that the same motion is performed by some other piscivorous birds, which are not provided with this particular bone.

Why was the cormorant formerly domesticated in this country?

Because it was trained to fish for its owner; it is still used in China for this purpose,

THE MAN-OF-WAR.

Why is the man-of-war bird so called?

Because it is one of the most formidable tyrants of the ocean. When in flocks, they attack sometimes even man himself. It is said that a cloud of them attacked a crew of French sailors upon the Island of Ascension, and, till some of them were struck down, endeavoured to snatch the meat from their hands. -- Jennings.

THE ORNITHORYNCUS.

Why is the ornithoryncus said to form the connecting link between the bird and beast?

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Because it has a bill like a duck, and paws webbed similar to that bird, but legs and body like those of a quadruped, covered with thick, close hair, with a broad tail to steer by. It is believed to lay eggs; it bears a claw on the inside of its foot, with a tube therein, through which it emits a poisonous fluid into the wounds which the claw inflicts.*

Why have birds a gizzard?

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Because it may answer the purposes of teeth to masticate their food; the gizzard being composed of thick and tough muscular substance, small in size, but more powerful in its action than the strongest jaw-bone. It consists of four distinct muscles large hemispherical pair at the sides, and a small pair at the two ends of the cavity. By their alternate action these muscles produce two effects; the one, a constant friction on the contents of the cavity, the other, a pressure upon them. These muscles are lined with a cuticle which is extremely callous, and which often becomes cartilaginous, and even horny, Reaumur and Spallanzani compelled geese and other birds to swallow needles, lancets, and other hard substances; in a few hours after which,the birds were killed and examined ;-the needles and lancets were uniformly found broken off and blunted, without the slightest injury having been sustained by the stomach. Swallowing pebbles also aids the action of the gizzard upon the food, the stones in some measure serving the purpose of teeth. Mr Hunter observed that the size of the pebbles is always in proportion to that of the gizzards. In the gizzard of a turkey he counted two hundred; in that of the goose, a thousand. (See page 84.)

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* Cunningham's Sketches of New South Wales. rupeds, page 58 of the present volume.

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Why does the gastric juice, in its effects, differ in different animals?

Because of the varieties of food on which they subsist. Thus,in birds of prey, as kites, hawks, owls, it only acts upon animal matter, and does not dissolve vegetables. In other birds, and in all animals feeding on grass, it dissolves vegetable matter, as grass, but will not touch flesh of any kind. This has been ascertained by making them swallow balls with meat in them, and several holes drilled through, to let the gastric juice reach the meat: no effect was produced upon it.

We may farther observe that there is a most curious and beautiful correspondence between this juice in the stomach of different animals, and the other parts of their bodies, connected with the important operations of eating and digesting their food. The use of the juice is plainly to convert what they eat into a fluid, from which,by various other processes, all their parts, blood, bones, muscles, &c, are afterwards formed. But the food is first of all to be obtained, and then prepared by bruising, for the action of the juice. Now, birds of prey have instruments, their claws and beak, for tearing and devouring their food, (which is animals of different kinds,) but those instruments are useless for picking up and crus seeds; accordingly they have a gastric juice which dissolves the animals they eat; while birds which have only a beak fit for pecking, drinking, and eating seeds, have a juice that dissolves seeds, and not flesh. Nay more, it is found, that the seeds must be bruised before the juice will dissolve them: this is found by making the experiment, in a vessel with the juice; and accordingly, the birds have a gizzard, and animals which graze have flat teeth, which grind and bruise their food before the gastric juice is to act upon it.

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Why have some birds more air-cells than others?
Because the quantity of air which they individually

contain, is proportioned to the influence which they exert on the locomotion of the body. Thus, in the eagle, and other birds of long flight, the bones which support the wings are filled with air; while in such as the puffin, whose wings are unequal to any lengthened flight, or the ostrich, which prefers to run, aircells are found in the greatest numbers within the bones of the leg and thigh.

These air-cells generally exist externally, between the muscles: the bones themselves, which in the mammalia contain marrow, are, in birds, filled with air. It has also been observed, by Mr Green, the celebrated anatomist, that, in young birds, a medullary substance is often observable in the bones; but as they grow up to maturity, it becomes absorbed, and the bone empty.

The beauty of this contrivance is equalled only by its importance. Independently of a perfect supply of air being thus furnished at all seasons, for the purposes of respiration, without any inconvenience to the general system, the relative weight of the body is materially diminished, the difficulty of breathing in a very rarefied atmosphere is counteracted, and the necessity of a frequent respiration during rapid flight may be dispensed with.

Why have birds that do not fly wings?

Because they assist in balancing the body as they

run.

Why are the necks of aquatic birds proportionally longer than those of land birds?

Because aquatic birds have to seek their food below the surface of the water on which they swim. The length of the neck generally increases in proportion to that of the legs.- Blumenbach.

Why does the neck of a bird acquire that double bend which makes it resemble the letter S?

Because the neck joints are not united by plane sur

faces, but by cylindrical eminences, which admit of a more extensive motion, as they also constitute real joints. Four or five of the pieces only bend forwards, while the lower ones are confined to flexion backwards. — Blumenbach.

Why do birds stretch out their necks when flying? Because they may become like sharp points, dividing the air, and diminishing the resistance.

Why are the beaks of birds so diversified in their form and structure?

Because each beak is adapted for receiving only certain kinds of food. Thus, some are long and pointed, others are broad and flat; others are hooked and curved.

Why is the freshness of an egg judged by its warmth? Because the egg, like most other living beings, maintains a temperature considerably above that of the surrounding medium; and, as long as it is alive, it resists putrefaction, under degrees of heat and moisture, which cause it to run rapidly into the putrefactive process as soon as it is dead.

Why, in several species of birds, have the male and female different plumage?

Because, as the female ceases in her old age to lay eggs, she obtains the male plumage. Blumenbach. Why is the body of a newly hatched bird covered with hair instead of feathers?

Because little tufts of hair, produced from one common bulb, are the rudiment of the future feather. In a few days a black cylinder appears, which opens at the extremity, and gives passage to the feather. The opposite end receives those blood-vessels, which supply the vessel-like substance in the barrel of the feather; when the stalk of the feather has received its complete growth, this vessel-like body is dried up, and presents the well known appearance called pith, in the barrel of quills.

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