+278. Slavery in South America.+ In South America we also meet with at least one case of a tribe, or part of a tribe, which is in clientage to another tribe. This is a subdivision of the third rank of the Mbaya, who voluntarily entered into a relation of clientage to the Mbaya, giving them service under arms, and in house and field, without being their slaves, being protected in return by the powerful and feared tribe.[688] The Guykurus carry on frequent wars to get captives, whom they keep in stringent servitude. "There is, perhaps, no tribe of South American Indians, among whom the state of slavery is so distinctly marked as among them." Slaves and free do not intermarry, lest marriage be profaned. There is no way in which a slave may become free.[689] The Guykurus are the strongest tribe in the valley of the Paraguay. They have horses and were called by the Portuguese Cavalleiros.[690] In Brazil it was thought that the cultivation of the country was impossible unless the Indians were made slaves. The early laws and orders of the kings of Portugal seem to reveal a sincere desire to control greed and cruelty. In 1570 private slave raids were forbidden and slavery was confined to those captured in public and just war. Lisbon, however, became a great slave mart by the law that slaves passing from one colony (Africa) to another (America) must pass through Lisbon and pay a tax there. Peter Martyr is quoted that slavery was necessary for Indians who, if they had no master, would go on with their old customs and idolatry. Slavery killed them, however. It did not make them laborers.[691] In general, in the valley of the Yapura, in the first half of the nineteenth century, slaves were war captives who were very unkindly treated.[692] The aborigines began to sell their war captives to Europeans soon after the latter arrived. They wanted rosewood especially, and they took Indians to Africa as slaves.[693] Boggiani[694] expresses the opinion in regard to the savages of the Chaco, as the meadow region on the Paraguay river is called, that slavery amongst a people of more civilized mores, is, for them, "an incalculable benefit," and that "to hinder slavery, in such circumstances, would be a capital error." "It is necessary to force them to come out of their brutelike condition, and to awaken their intelligence, which is not wanting, if they receive practical and energetic direction." Bridges[695] says that one Fuegian is thrown into clientage to another by their mode of life. "For a young man, with no wife and few relatives, must live with some one who can protect him, and with whom he can live in comfort, whose wife or wives can catch fish for him, etc."