We have not exhausted the list of hypotheses advanced, to explain the nearly constant sterility attending the intercourse between Australians and Tasmanians and the English. It has also been said that for the most part the intercourse between the two races was accidental, momentary, and that consequently the native woman has a much greater chance to become pregnant by her savage husband than by her European lovers, and that the rarity of Australian Mulattoes had no other cause. M. de Freycinet seems to have accepted this explanation. “No _permanent_ alliances are formed between the two peoples, though we find here and there some Mulattoes; but these are merely the result of some transitory connections of Europeans with Australian women.”[73] We would first observe that the number of mongrels is in many countries much more considerable, if the intermixture is effected in the same manner as is notably the case in South Africa. There are cross-breeds in several of the Polynesian Islands, where the Europeans have never permanently settled, but only appeared temporarily. There should, therefore, be a good number of them in the Australian colonies, even if it were true that the Whites have never formed a permanent alliance with the native females. It can, however, not be doubted, that more or less enduring alliances have taken place between the two races, namely, that many Whites have kept for months and years Australian concubines under their roof.[74] This fact positively results from the controversy raised by Count Strzelecki. This celebrated traveller, who has visited America and Oceania, remarked that the native women, after having once lived with the white race, become sterile with the men of their own race, though they may still be capable of becoming pregnant by white men. He asserts that he has collected hundreds of such cases among the Hurons, Seminoles, Araucaños, Polynesians, and Melanesians. He does not attempt to explain this strange phenomenon, which, he observes, is owing to some mysterious law, and which appears to him to be one of the causes of the rapid decay of indigenous populations in regions occupied by Europeans.[75] Mr. Alex. Harvey says that Professors Goodsir, Maunsel, and Carmichael have, from various sources, ascertained that Count Strzelecki’s assertion is _unquestionable_, and must be considered as the expression of a law of nature.[76] M. de Strzelecki has not specified that the sterilisation of the native females was the consequence of the procreation of cross-breeds. He merely speaks of sexual relations in general; and it appears to result from the text, that a native woman who has cohabited for some time with a European, becomes sterile in the intercourse with men of her own race, even if she has not produced a child.