“The Emu,” continued Uncle Thomas, “inhabits the plains and ‘bushes’ of Australia, but so numerous are the enemies by which they are now surrounded,—settlers, bushmen, Wolves, and Wild-Dogs, that the race seems threatened with extirpation. Not only are their eggs reckoned good food, but some parts of their flesh, though not highly prized, is still palatable. Besides their swiftness, in which they resemble the Ostrich, they kick with great vigour; and are thus able to defend themselves against the Dingo or native Dog, but the trained one, which is brought to attack them on the side, is almost certain of victory. “There is a curious provision of nature,” continued Uncle Thomas, “in the construction of this bird, consisting of an internal pouch, connected with the windpipe, the use of which long puzzled naturalists. At length some one more ingenious than his neighbours, or better acquainted with the animal’s habits, solved the difficulty by pointing out that it was intended to enable it to escape from the inundations to which the plains of New Holland are particularly liable, and without which provision the heaviness of the Emu would probably cause it to sink and be drowned.” “How can it prevent it from sinking?” asked Mary. “Pretty much in the same manner,” said Uncle Thomas, “as fishes are enabled at pleasure to rise to the surface of the water. Fishes, you know, are furnished with what is called an air-bladder, which they have the power of filling and emptying at pleasure; when they wish to sink they force out the air, and their bodies being thus rendered specifically heavier than water, descend; and on the contrary, when they wish to rise, by inflating it they ascend. The ‘air-bladder,’ if I may so call it, of the Emu acts much in the same way. As the animal walks about it is, of course, of no use, and is allowed to remain empty; but, whenever it is threatened with drowning it is inflated, and the Emu is thus enabled to float with its head above the surface of the water.