elders solemnly sever the intestines with a sharp splinter of wood taken from a bush of a certain sort (_mukeo_), “and they announce that they are cutting the clan _kutinyarurira_, by which they mean that they are severing the bond of relationship which exists between the pair. A medicine man then comes and purifies the couple.”[93.1] In all these cases we may assume with a fair degree of probability that the old prohibition of marriage between cousins is breaking down, and that the expiatory sacrifice offered when such a marriage does take place is merely a salve to the uneasy conscience of those who commit or connive at a breach of the ancient taboo. [Sidenote: The mutual avoidance of male and female cousins is probably a precaution against a criminal intimacy between them.] Thus the prohibition of marriage between cousins, and the rules of ceremonial avoidance observed in some tribes between persons who stand in that relationship to each other, appear both to spring from a belief, right or wrong, in the injurious effects of such unions and from a desire to avoid them. The mutual avoidance of the cousins is merely a precaution to prevent a closer and more criminal intimacy between them. If that is so, it furnishes a confirmation of the view that all the customs of ceremonial avoidance between blood relations or connexions by marriage of opposite sexes are based simply on a fear of incest. [Sidenote: The mutual avoidance between a man and his wife’s relations seems to be partly grounded on a fear of rendering the wife infertile.] The theory is perhaps confirmed by the observation that in some tribes the avoidance between a man and his {94} wife’s mother lasts only until he has had a child by his wife;[94.1] while in others, though avoidance continues longer, it gradually wears away with time as the man and woman advance in years,[94.2] and in others, again, it is observed only between a man and his future mother-in-law, and comes to an end with his marriage.[94.3] These customs suggest that in the minds of the people who practise them there is a close connexion between the avoidance of the wife’s relations and the dread of an infertile marriage. The Indians of Yucatan, as we saw, believe that if a betrothed man were to meet his future mother-in-law or father-in-law, he would thereby lose the power of begetting children. Such a fear seems to be only an extension by false analogy of that belief in the disastrous consequences of illicit sexual relations which we dealt with in an earlier part of this chapter,[94.4] and of which we shall have more to say presently.[94.5] From thinking, rightly or wrongly, that sexual intercourse between certain persons is fraught with serious dangers, the savage jumped to the conclusion that social intercourse between them may be also perilous by virtue of a sort of physical infection acting through simple contact or even at a distance; or if, in many cases, he did not go so far as to suppose