The consequence of this racial purity, universally valid in Nature, is not only the sharp outward delimitation of the various races, but their uniform character in themselves. The fox is always a fox, the goose a goose, the tiger a tiger, etc., and the difference can lie at most in the varying measure of force, strength, intelligence, dexterity, endurance, etc., of the individual specimens. But you will never find a fox who in his inner attitude might, for example, show humanitarian tendencies toward geese, as similarly there is no cat with a friendly inclination toward mice.