What has been said about the mother's sister applies also to the father's brother who, under father-right, is often regarded as a substitute father. His wife would then act as a substitute mother, especially in case of adoption. Under mother-right again, the mother's sister's husband would be the substitute father.
XVIII. The Special Relations of Mother-right and FatherXviii. The Special Relations of Mother-right and Father- right.—Among the people closely related to the parents there are, however, some to whom no extension of an already exist ing kinship attitude is possible. The grandparents obviously be long here, and also the father's sister and the mother's brother. Under mother-right and exogamy, the father's sister is never of the mother's kin and cannot be assimilated to the mother while, though of the father's kin, she is not of his sex and, therefore, cannot be assimilated to him. Under unilateral father-right, she again is the chief kinswoman of the child. The mother's brother occupies the same singular position both under mother-right and father-right. New attitudes have to be built towards these rela tives and, as a rule, we find also special terms for them.
The children of the mother's sister and of the father's brother, or "parallel cousins" as they are called in Anthropology, are usu ally regarded by a savage child as his "secondary" brothers and sisters and addressed by these terms. To them the primary family attitude is also partially extended, as it is to their parents.
The children of the mother's brother and father's sister—the "cross-cousins" as they are technically called—usually require the creation of a new type of bond. The terminologies of the cross cousins often present strange verbal assimilations. Thus, in matri lineal societies, the paternal cross-cousin is often called "Father"; and under father-right mother's brother's daughter is labelled "Mother." If we consider, however, that under mother-right, the paternal cross-cousin (father's sister's son) is not Ego's real kinsman—that he is related to Ego only as the father's nearest kinsman—then the verbal identification is less strange. The appel lation then really means : "that man who is to me only in so far related as he is my father's nearest in blood." And a similar
psychological attitude underlies the strange use of Mother to a cross-cousin and other anomalous terms of this type.
XIX. The Elimination of Sex from Workaday Life.—The unilateral principle which declares that kinship is counted through mother or father only (compare above, IV.) means, in fact, looked at concretely as it enters the life of an individual, that the family bonds are extended on one side only. An important aspect of this one-sided extension is the development of rules of exogamy out of rules of incest. These rules eliminate sex out of the household and the clan respectively. Incomprehensible in their biological function, since biologists agree that occasional inbreeding is in nocuous, they can be accounted for by the incompatibility of sexual interest with practical co-operation in everyday life. The emotional tension which accompanies erotic play, the jealousies and dissensions which it arouses as well as its obsessive and dis tractive influence, make it difficult to mingle sex with serious pur suits. Hence war and hunting, agriculture and trading enterprises, religious and public ceremonial, are often hedged round with sexual tabus.
Domestic life and all those relations which start in the family, that is parent and child, brother and sister, are permanently pro tected from the upsetting influence of sex by the tabu of incest. Later on, when the savage child, sexually ripe at an early age, enters the wider group of his village community and tribe, an important division is established in all his associations by the unilateral principle. Some people, male and female, become his natural associates in work, legal interests and spiritual concerns. These are his wider kindred, his clansmen and clanswomen, to whom he extends the modified and diluted family attitude, com prising among others, the rules of incest which here become the much wider and weaker tabus of exogamy. The other group consists of women with whom he may amuse himself and pursue his amorous inclinations, and of men with whom he enters into relations of more or less friendly rivalry or reciprocity.