Note 33 — Chapter III
Henry P. (Henry Pomeroy) Horton translation
As to their sexual relations, there could not be any question of promiscuity among these peoples. Each horde is divided into three age-classes, and the union of a member of one of these classes with a member of another is forbidden. The cause of this prohibition is not certain. Grosse33 (as well as other authors34) is of the opinion that it lies in the fact that these peoples discovered the unfavorable effects of consanguineous unions upon the children, and that this discovery led to the prohibition.35 Other authors believe that the hordes which practiced this exclusion, without suspecting its importance, ran less danger of extinction than those which did not practice it.36