There is less variety among the individuals of non-human races than among individual men, just as there is less variety among individual savages than among the members of a civilised community. But there is mental diversity among all beings, and we only need to whittle our observation a little to recognise the fact. You never hear the keeper of a menagerie or any intelligent associate of dogs, horses, birds, or insects say there is no individuality among these animals. Brehm, the great German naturalist, assures us that each individual monkey of all those he kept tame in Africa had its own peculiar temper and disposition. And this is no more than what everyone who knows anything about it knows to be true of dogs, horses, cats, cattle, birds, and even fishes and insects. Any intelligent dog-fancier or pigeon-fancier can tell you the personal peculiarities of every one of the fifty or a hundred dogs or pigeons in his charge. He has watched and studied them since they came into existence, and through this continuous association he has come to _know_ them. He simply makes discriminations that are not made by the casual or superficial observer. The Laplander knows and names each reindeer in his herd, though to a stranger they are all as much alike as the multitudes on an ant-hill. The Peckhams of Milwaukee, those indefatigable investigators of spiders and insects, are constantly telling us of the wonderful individuality possessed by these lowly lessees of our fields and gardens. In their work on ‘The Habits and Instincts of the Solitary Wasps,’ speaking of the ammophiles, these authors say: ‘In this species, as in every one that we have studied, we have found a most interesting variation among the different individuals, not only in methods, but in character and intellect. While one was beguiled from her hunting by every sorrel blossom she passed, another stuck to her work with indefatigable perseverance. While one stung her caterpillars so carelessly and made her nest in so shiftless a way that her young could survive only through some lucky chance, another devoted herself to these duties not only with conscientious earnestness, but with an apparent craving after artistic perfection that was touching to see.’ The variation in the mental phenomena of animals, including man, is partly innate, and partly the result of environment or education. Animals not only vary in their mental qualities, but they also _inherit_ these variations, just as they do physical properties and peculiarities. Evidence of this is furnished by every new being that comes into the world. Insanity runs in families, and so does genius and criminality. Even the most trifling idiosyncrasies are often transmitted, not only by men, but also by dogs, horses, and other animals. Such qualities of mind as courage, fidelity, good and bad temper, intelligence, timidity, special tastes and aptitudes, are certainly transmitted in all the higher orders of animal life.