Yet there is evidence here of a natural association by virtue of which the fear of marriage with one's own mother, which, though not caused by the exogamous prohibition, is nevertheless greatly strengthened by it, is directly carried over to the mother-in-law. Between a woman and the husband of her daughter there thus arises a state of taboo such as is impossible between mother and son because, from the time of his birth on, they are in close and constant relation with each other. In consequence of the above-mentioned association, mother and mother-in-law, or father and father-in-law, form a unity analogous to that which obtains between man and wife. What is true of the husband, is also true in the case of the wife; similarly, what holds for the mother of the husband holds no less for the mother of the wife. Striking evidence of the effect of an association of ideas that is perfectly analogous to the one underlying the taboo of the mother-in-law, is offered by a custom which is doubtless generally only local in scope and yet is found in the most diverse parts of the earth, thus showing plainly that it is autochthonous in character. I refer to the custom of so-called father-confinement or 'couvade.' This custom prevails in various places, occurring even in Europe, where it is practised by the Basques of the Pyrenées, a remarkable fragment of a pre-Indo-Germanic population of Europe. Due, probably, to the heavier tasks which these people impose upon women, it here occasionally occurs in an exaggerated form. Even after the mother has already begun to attend to her household duties, the father, lying in the bed to which he has voluntarily retired, receives the congratulations of the relatives. Custom also demands that he subject himself to certain ascetic restrictions, namely, that he avoid the eating of certain kinds of food. The custom of couvade is clearly the result of an ideational association between husband and wife--one that is absolutely analogous to that between the two mothers of the married couple. The child owes its existence to both father and mother. Both, therefore, must obey the regulations which surround birth, and thus they are also subject to the same taboo. Just as there is very commonly a taboo on the mother and her new-born child, so also, in the regions where couvade exists, is this transferred to the husband.