Of particular interest in this connection is the displacement of feelings originally directed to the parents towards _relatives in law._ Since by marriage one partner in the marriage is supposed to have entered into the family of the other, and, in virtue of the partial identification of the two partners through common ties of interest and affection, may really be said to have in some measure effected such an entrance, it is not altogether surprising to find much the same conflict of tendencies centering about the new relatives acquired by marriage as that which formerly centred round the relatives by blood. Thus on the one hand we find among primitive peoples the same taboos and avoidances practised in the one case as in the other. In some places, for instance, a man may have no dealings with some or all of the members of his wife's family, nor a wife with those of her husband's[106]. On the other hand a number of practices indicate that connections of an intimate kind between relatives by marriage are, under certain circumstances at any rate, regarded as permissible and appropriate. Such, for instance, is the widespread custom of the Levirate[107], whereby a man is expected to take unto himself his deceased brother's wife or the scarcely less frequent usage of the Sororate[108] whereby a man marries his deceased wife's sister--practices which seem to have made their influence felt (negatively) in our own table of relatives with whom wedlock is forbidden, including, as this does, not only blood relatives but relatives by marriage[109]. [Sidenote: Parent-in-law and child-in-law] [Sidenote: Difficulties caused by parent fixation on the part of husband or wife]