234 AFRICAN POLITICAL SYSTEMS
his past and present life, if his sacrifice is to be favourably accepted by the spirits. That elder in the clan who possesses these qualities to the highest degree is recognized as the omusalisz munene ('the great sacrificer') who is called to perform private sacrifices of great importance and, among the Logoli, also the ovwali, the public sacrifice to the tribal ancestor and deity. His office is not hereditary, but dependent upon personal qualities.
Among the various 'experts', the dream-prophet and the rainmaker appear to have wielded political power of a kind, as, through the practising of their arts, they could influence the activities, not only of single individuals, but of larger groups of people. The dream-prophet, as has been stated, was consulted on the probable outcome of war expeditions, on the advisability of migrations, the probability of epidemics, and on similar matters of wider concern, while the rain-maker, through his alleged ability of withholding rain and of directing the rainfall, not only in general, but in respect of particular gardens, had the power of an executive organ in the administration of justice. These two experts, however, form categories of their own. Their knowledge is by virtue of inherited secret medicines and spells, and they wield it independently of their clan—and, in the case of the rain-maker, even of their tribal affiliations. Their special knowledge, therefore, does not appear to have lent them authority beyond that implied in their specific practices.
(/) Age. Old age, finally, was the most general condition of political leadership and was socially marked through the institution of circumcision age-grades. The recognition of primogeniture for the regulation of inheritance and succession lends seniority a superior status in all kinship relations. Generally speaking, it is always the oldest member of a group of kinsmen whose opinion carries the greatest weight on matters concerning that group. Adult sons show more obedience and respect to their father's oldest brother than to the father himself, and after their father's death his authority is not immediately transmitted to the oldest son, but first to the next oldest brother who is still alive.
The authority implied in old age is further strengthened by notions connected with the ancestor cult. One of these is that old age is regarded as a necessary condition of performing sacrifices, as it requires a mind that is free from sexual desire and that possesses other qualities characteristic of old age, such as wisdom,