Again, if Mr. Crawley reads on, he will find, I think, that the context of Mr. Robertson Smith’s argument shows him not to have held that exogamy arose in ‘the feeling that it is indecent for “house-mates”’ (or tent-mates) ‘to marry.’ For Mr. Robertson Smith adds, ‘it will not do to turn this argument round, and say that the pre-Islamic law of bars to marriage may have arisen ... in virtue of a custom that every wife and her children shall have their own tent.[50] In any case, we cannot speak of ‘house-mates’ before there were houses. But if for ‘house-mates’ we read ‘hearth-mates,’ then no sense of ‘indecency,’ as on Mr. Crawley’s theory, need necessarily attend their marriage, for hearth-mates may be of different totems, derived from different mothers, and may be marriageable enough, at least as far as totem law is concerned. A, male, an Emu, marries B, a Bandicoot, and C, a Grub. His children by B have the Bandicoot totem, his children by C have the Grub totem. As far as totem law goes, these children may intermarry, but this is not allowed in practice to-day. Mr. Mathews says, of the Kamilaroi, ‘in order to prevent such a close marriage’ (of brother and sister on the father’s side), ‘every tribe has strict social customs, founded upon public opinion, which will not tolerate the union of a man with a woman whose blood relationship is considered too near.’[48] Australian ethics, long trained under the old totem and phratry prohibitions, are now sufficiently enlightened to reject unions which we also forbid. But it cannot have been so in the beginning, or the totem and phratry tabus on marriage would have had no occasion to exist. It would have sufficed to say, ‘Thou shalt not marry thy sister, or mother,’ and the totemic rule would have been a cumbrous superfluity. Superfluous it would have been, even under the hypothetical ‘group marriage system,’ where the law would have run ‘Thou shalt not marry thy group-sister or group-mother.’ While Mr. Matthews gives a kind of bye-law, forbidding marriage, under female descent, with the paternal half-sister, Mr. Fison avers that the Kamilaroi do allow such unions. ‘It is marriage within a phratria,’ but not within a totem.[49] The fact was denied, or at least questioned, by many correspondents, but Mr. Fison believed it to be authentic. ‘The natives justified it on the ground that the parties were not of the same _mudji_’ (totem). Apparently these natives, who let a man marry his father’s daughter, had not arrived at an objection to unions of ‘too near flesh.’ But mere decadence, under European whisky, may be the explanation. Mr. Matthews denies, as we saw, what Mr. Fison asserts, as to the Kamilaroi. Mr. Crawley writes, ‘if we apply to the word “indecent” the connotation of sexual tabu ... and if we understand by “house-mates” those upon whom sexual tabu concentrates, we have explained exogamy.’[50]