account for the comparatively large number of mongrels in that part of the continent. Other statements also, adduced as evidence for the hypothesis of M. Broca, have proved more or less untrustworthy. Thus the alleged sterility of the mulattoes of Jamaica[1672] has been disputed by other writers.[1673] So also v. Görtz’s statement that the children of the Dutch and Malay women in Java (Lipplapps) are only productive to the third generation,[1674] has been called in question.[1675] Yet, although we may consider it certain that the diversities even between the races which least resemble each other are not so great but that, under favourable conditions, a mixed race may easily be produced, I do not deny the possibility of crossing being, to a certain extent, unfavourable to fertility. The statements as to the rapid increase of some mixed races do not prove the reverse. For the bad result of crossing would not necessarily appear at once; and a drop of pure blood would be sufficient to increase fertility, just as, when a hybrid is crossed with either pure parent species, sterility is usually much lessened.[1676] It is a remarkable fact that mixed marriages between Jews and persons of other races are comparatively infertile. In Prussia, these marriages have been separately registered since 1875, and between that year and 1881 there was an average of 1·63 to a marriage, whereas, during the same period, pure Jewish marriages resulted in an average of 4·41 children or very nearly three times as many. In Bavaria, between 1876 and 1880, the numbers were only 1·1 per marriage against 4·7 children to purely Jewish marriages. And this conspicuous infertility implies greater sterility. Among fifty-six such marriages, with regard to which Mr. Jacobs ascertained the results, no fewer than nine were sterile, _i.e._, 18 per cent.,—a striking contrast to the number of sterile marriages which he found in seventy-one marriages between Jewish cousins, where the percentage of sterility was only 5·4 per cent.[1677] Mr. Jacobs, however, informs me that it has been suggested that this infertility may be due rather to the higher age at which such marriages are likely to take place. There is still a strong feeling against them among Jews, which is only likely to be overcome after independence of thought and position has been reached. At the same time Mr. Jacobs does not consider this sufficient to account for the very great discrepancy. But we must not, of course, take for granted that the crossing of any two races has the same effects as the crossing of Jewish and non-Jewish Europeans seems to have.