It is no less evident to me that the survivors cannot always owe their preservation to a combination of happy chances. Among the immense majority the victory can only be due to certain special advantages, which are not enjoyed by those who succumb. The result of this _struggle for existence_ is, then, the destruction of all the inferior individuals, and the preservation of those individuals only which possess some kind of superiority. This is what Darwin calls _Natural Selection_. I can scarcely understand how these two phenomena can be doubted or even denied. They do not constitute a theory, but are facts. Far from being repugnant to the mind, they seem inevitable, the consequences follow with a sort of necessity and fatality resembling the laws of the inorganic world. The term _selection_ gives rise to criticism, and the language of Darwin, at times too figurative, renders plausible the objection of those who have reproached him with attributing to _nature_ the part of an intelligent being. The word _elimination_ would have been more exact. But much of this should have been prevented by the explanations given by the author. Besides, it is evident that the struggle for existence entails the elimination of individuals who are less able to sustain it, and that the result exactly resembles that produced by _unconscious human selection_. Then _heredity_ intervenes among beings which are free as well as among those which we bring up in captivity. It preserves and accumulates the progress made by each generation in any direction, and the final result is the production in the organism of certain appreciable anatomical and physiological modifications. The words _superior_ and _inferior_ should here only be taken as relative to the conditions of existence in which animals and vegetables are placed. In other words the individual which is best adapted to those conditions, will be superior and will conquer in the struggle for existence. For instance, the black rat and the mouse have both to struggle against the brown rat which entered France during the last century from the banks of the Volga. The black rat was almost as large and as strong as his adversary, but less ferocious and less prolific. It has been exterminated in spite of refuges which are inaccessible to its enemy. The mouse, which is much weaker, but at the same time much smaller, can retire into holes which are too small for the brown rat; it has therefore survived the black rat.