It is not my business to deal with this question here, to trace the limits of civilizable humanity, or to examine the rights and duties of civilized men to each other relatively to the rest of the living world; or, in other words, to what extent civilized man should have the relative right of subjecting other living beings, exploiting them in his own interests, nourishing them, or eventually exterminating them for the safety of his own existence. As regards the animal and vegetable kingdoms, from the amoeba to the orang-utan, the question is simple enough and settled. It is much more difficult to decide for men and for peoples separated from us by great racial differences. I must emphasize the profoundness of this difference. It is evident that the higher cultivated races, or rather blends of races, which live to-day will do better to live in peace than to mutually exterminate each other. It is necessary to discuss these questions at the risk of hurting the feelings of sentimental persons. But what is the use of being blind to such patent facts? It is not too soon to look closely into the future, and it is only thus that we can arrive at any useful result. The natural rights of man should evolve more and more from a complex of social rights and duties toward a single great group, which we may call _civilized humanity_, the relative limits of which can only be traced by repeated trials and by practical experience. The instincts of the wild beast are still so deeply rooted, even in civilized men, that they can only be adapted gradually and even painfully to a natural right thus understood and limited. We must honestly admit that such a right only merits very relatively the denomination of _natural rights_. In fact, social rights are necessarily artificial in man. A few elementary rights and duties only are quite natural, especially in the sexual domain. We are concerned here with adaptations in the form of instincts which serve for the support and development of the family, as well as for the protection of the individual. Among these we may mention the right to life, the duty of labor and the right to labor, the right of the infant to be nourished by its mother and to be cared for and protected by its parents, the duty of parents to nourish their children, the duty of the husband to protect his wife, the right to obtain nourishment from the animal and vegetable kingdoms, the right to satisfy the sexual appetite, etc. There exists, however, a series of other rights and duties, which are so necessary that they may be termed natural. Such are the right to possess a dwelling place; to defend one's life against attack; to think and believe what one wishes so long as one does not impose one's ideas and faith on others; the duty to respect the life and property of one's neighbor; the duty to give a healthy and sufficient education to youth, both in body and mind, etc.