It is believed that all the mountain people of the northern half of Luzon, except the Negritos, came to the island in some of the earliest of the movements that swept the coasts of the Archipelago from the south and spread over the inland areas -- succeeding waves of people, having more culture, driving their cruder blood fellows farther inland. Though originally of one blood, and though they are all to-day in a similar broad culture-grade -- that is, all are mountain agriculturists, and all are, or until recently have been, head-hunters -- yet it does not follow that the Igorot groups have to-day identical culture; quite the contrary is true. There are many and wide differences even in important cultural expressions which are due to environment, long isolation, and in some cases to ideas and processes borrowed from different neighboring peoples. Very misleading statements have sometimes been made in regard to the Igorot -- customs from different groups have been jumbled together in one description until a man has been pictured who can not be found anywhere. All except the most general statements are worse than wasted unless a particular group is designated. An illustration of some of the differences between groups of typical Igorot will make this clearer. I select as examples the people of Bontoc and the adjoining Quiangan district in northern Nueva Vizcaya Province, both of whom are commonly known as Igorot. It must be noted that the people of both areas are practically unmodified by modern culture and both are constant head-hunters. With scarcely one exception Bontoc pueblos are single clusters of buildings; in Banawi pueblo of the Quiangan area there are eleven separate groups of dwellings, each group situated on a prominence which may be easily protected by the inhabitants against an enemy below them; and other Quiangan pueblos are similarly built. As will be brought out in succeeding chapters, the social and political institutions of the two peoples differ widely. In Bontoc the head weapon is a battle-ax, in Quiangan it is a long knife. Most of the head-hunting practices of the two peoples are different, especially as to the disposition of the skulls of the victims. Bontoc men wear their hair long, and have developed a small pocket-hat to confine the hair and contain small objects carried about; the men of Quiangan wear their hair short, have nothing whatever of the nature of the pocket-hat, but have developed a unique hand bag which is used as a pocket. In the Quiangan area a highly conventionalized wood-carving art has developed -- beautiful eating spoons with figures of men and women carved on the handles and food bowls cut in animal figures are everywhere found; while in Bontoc only the most crude and artless wood carving is made. In language there is such a difference that Bontoc men who accompanied me into the northern part of the large Quiangan area, only a long day