"They are a large tribe of negroes, living along the White Nile," replied the Doctor, "and are thought to number nearly, if not quite, three millions. For more than two hundred miles their villages are scattered along the river, forming an almost continuous line. They live partly by hunting and fishing, and formerly they made quite a revenue by selling slaves to the dealers who came from Khartoum and other parts of Egypt. "They made war upon neighboring tribes farther back from the river, and sold their prisoners into slavery; and sometimes they sold their own people. It was not unusual for a Shillook to sell his own children when a good price was offered, especially if his family was large and his affairs were not prosperous." Frank asked if they could land among the Shillooks and see how they lived. Doctor Bronson said it was not altogether safe to go among them, as they have been badly treated by the Turks and Egyptians, and are not specially friendly. As the Doctor was speaking the steamer rounded the point of an island, and the dragoman called their attention to a number of conical huts of grass among the low trees near the shore. "That is a Shillook village," said Abdul, "and several of the inhabitants are standing by the edge of the river." The boys ran below for their glasses, and were back again in a few moments. They made out the negroes to be tall, well-formed men, most of them fully six feet in height, and entirely without clothing, with the exception of two, who had strips of cloth around their waists. Abdul said the full dress of the Shillooks was a waist-cloth and a string of beads, but they were not always particular about arraying themselves. [Illustration: A BIRD OF THE WHITE NILE.] Back of the village was a field of cotton and another of beans, and there was every indication that the Shillooks had a fertile soil to cultivate. Abdul said their products were the same as near Khartoum, but they had very few fruit-trees, and their gardens were not carefully tilled. The steamer stopped near one of the villages to take wood, and after a consultation with the captain Abdul said the boys could go on shore, but must not wander from the immediate vicinity of the boat. The Shillooks are apt to be treacherous, and sometimes a lance or an arrow is sent from the bushes when there is nothing to indicate the presence of danger. When kindly treated their confidence is easily secured, but they have been subject to so much ill-usage at the hands of the slave-dealers that it is no wonder they are suspicious.