M. de Quatrefages, in order to explain the difference of results produced by the intermixture of the Dutch and the Malays at Java, and other Dutch colonies, supposes that this difference is due to the influence of mediums. This is possible; but there are other influences which must be taken into account, namely, the numerical proportion of either of the two races who intermarry. Where the Europeans are few in number, the Mulattoes of the first degree are also very few; those who intermarry between themselves are still less numerous, and the rest ally themselves with the parent stock, chiefly with the indigenous race, which is preponderating. Where, on the contrary, the European population is considerable, the Mulattoes of the first degree are sufficiently numerous to constitute a sort of intermediate caste, which, without altogether escaping a recrossing, contract nearly all their alliances with their equals.[40] In the first case, most individuals of mixed blood approximate more to the indigenous race than to the foreign; that is to say, that the Mulattoes of the second, third degree, etc., are much more numerous than the Mulattoes of the first degree. But in proportion as a recrossing is effected, the influence of hybridity diminishes, and becomes effaced. In the second case, on the contrary, the greater part of the Mulattoes are of the first degree,[41] and, much more than the rest, subject to the influence of hybridity; and if it be true that hybridity causes a diminution of fecundity, it is easily understood that the prolificness must vary according to the relative proportion of the two races. Now, Batavia is the great centre of the population of the India Archipelago; there the Europeans are most numerous; it is chiefly there that the Lipplappen form a distinct class, and it is precisely there that their defective prolificness is found. I do not pretend to say that this interpretation is perfectly correct; I merely advance it as an hypothesis to be verified. Here, however, we have a fact which may enhance its value. I borrow it from the work of Prof. Waitz. It is known that a large number of Chinese are found in the eastern and western isles of the Indian Archipelago. They are relatively less numerous in Java and Sumatra, where their commerce cannot sustain the competition with the Dutch. “The descendants of the Chinese and the Malay women in the eastern islands of the Indian Archipelago,” says Waitz, “soon become extinct; whilst at Java, _where the pure Chinese are few in number_. The Malay-Chinese Mulattoes amount to 200,000.”[42]