In Africa we find many of the characteristics noted above. In the Purrah the novices retire to a holy precinct, and are said to endure extreme hardship. Only warriors thirty years of age can be initiated.[34] In the Mumbo-Djumbo only youths older than sixteen are admitted.[35] The other conditions are similar to those of the Purrah. In the Simo organization novices were circumcized and lived seven years in the woods.[36] In the Mwetyi Society, in addition to probations, the youths adopt a taboo of certain foods or drinks, to which they remain faithful ever after.[37] In the Ndembo Society novices are shot by a rattle, and fall down as if dead. They are then carried away to some holy precinct, where often as many as from twenty to fifty individuals remain at the same time. At this place they stay sometimes as long as three years. Their bodies are supposed to disintegrate during this time. When they are supposed to return, the shaman gathers their bones and restores them to life. On the return to their villages, they behave like unknown children, fail to recognize their relatives, to understand their own language, etc.[38] In the Nkimba similar conditions are found.[39] The variability of the method and concept of initiation is thus seen to be enormous. It might be interesting in this connection to point out how certain ideas will cluster around initiation in one large geographical area, and how the same ideas will cluster around a different cultural complex in another large geographical area. For instance, in the South Seas and in Africa, initiation is found generally associated with tests or probations; whereas in North America tests are not associated with initiation into the society, but with the obtaining of visions at the age of puberty.