The clever breeder, whom I have just mentioned, as well as all other breeders, have moreover only attained their end by means of minute care in the choice of the animals from which they breed. Now, between human races there can be no question of _selection_. The unions have always taken place by chance. Moreover, in the immense majority of cases, the continual intervention of individuals of pure race increases, and prolongs the confusion. This absence of uniformity, which astonishes polygenists, is easily explained by those who only consider human groups as _races_. From a general point of view it is very instructive; if it brings forward _diversity of races_, it attests _specific unity_. It is not between species that crossing presents similar phenomena. But nevertheless, through this disorder, there appear in the mixed populations of our colonies, general common characters, which have attracted the attention of travellers, and have been described. Moreover, when, in consequence of some circumstance, the products of these crossings are isolated and protected from new mixtures, the race becomes characterised with rapidity. The Cafusos, Basters, and Griquas, may be quoted as examples. Even the Pitcairn islanders, at the time of Beechey’s visit, were beginning to become uniform. VII. In the crossings between unequal human races, the father almost always belongs to the superior race. In every case, and especially in transient amours, woman refuses to lower herself; man is less delicate. From the point of view of the future of the mixed races, the predominant action of one sex over the product should have then great importance. The question has been put since the origin of societies, as is testified by the laws of Manou; it has been repeatedly discussed by thinkers and physiologists. Each sex has had its champions; and numerous facts have been quoted on both sides. Considering everything, it appears to me impossible to avoid deciding in favour of _equality of action_. Nevertheless this equality is purely virtual; it can, in fact, only exist on the condition of an equal generating energy in both parents. As soon as the equilibrium is interrupted, the stronger sex predominates, and the product shows this superiority. The experiments of Girou de Buzareingue upon the procreation of the sexes, appeared to me to be most decisive in this respect. Now what is true of the whole of the organism is equally true of its different parts, functions, and energies. In the formation of a new being, the action of heredity is divided into as many _cases_ as there are _characters_ to transmit. Both father and mother tend to reproduce themselves in their offspring; there is, consequently, a struggle between both natures. But the battle, if we may use the expression, results in a number of single combats in which each parent may be in turn victor or vanquished.