What enables the shepherd to perform the long and toilsome journies across Africa is the camel, emphatically called by the Arabs, the _ship of the desert_. He seems to have been created for this very trade, endued with parts and qualities adapted to the office he is employed to discharge. The driest thistle, and the barest thorn, is all the food this useful quadruped requires, and even these, to save time, he eats while advancing on his journey, without stopping, or occasioning a moment of delay. As it is his lot to cross immense deserts, where no water is found, and countries not even moistened by the dew of heaven, he is endued with the power at one watering-place to lay in a store, with which he supplies himself for thirty days to come. To contain this enormous quantity of fluid, Nature has formed large cisterns within him, from which, once filled, he draws at pleasure the quantity he wants, and pours it into his stomach with the same effect as if he then drew it from a spring, and with this he travels, patiently and vigorously, all day long, carrying a prodigious load upon him, through countries infected with poisonous winds, and glowing with parching and never-cooling sands. Though his size is immense, as is his strength, and his body covered with a thick skin, defended with strong hair, yet still he is not capable to sustain the violent punctures the fly makes with his pointed proboscis. He must lose no time in removing to the sands of Atbara; for, when once attacked by this fly, his body, head, and legs break out into large bosses, which swell, break, and putrify, to the certain destruction of the creature. Even the elephant and rhinoceros, who, by reason of their enormous bulk, and the vast quantity of food and water they daily need, cannot shift to desert and dry places as the season may require, are obliged to roll themselves in mud and mire, which, when dry, coats them over like armour, and enables them to stand their ground against this winged assassin; yet I have found some of these tubercles upon almost every elephant and rhinoceros that I have seen, and attribute them to this cause. All the inhabitants of the sea-coast of Melinda, down to Cape Gardefan, to Saba, and the south coast of the Red Sea, are obliged to put themselves in motion, and remove to the next sand in the beginning of the rainy season, to prevent all their stock of cattle from being destroyed. This is not a partial emigration; the inhabitants of all the countries from the mountains of Abyssinia northward, to the confluence of the Nile and Astaboras, are once a-year obliged to change their abode, and seek protection in the sands of Beja; nor is there any alternative, or means of avoiding this, though a hostile band was in their way, capable of spoiling them of half their substance; and this is now actually the case, as we shall see when we come to speak of Sennaar.