This happiness has not been acquired through any providential "miracles." No God came down from His Heaven to alleviate human misfortunes. It is man, and man alone, who, by his genius and his labours, has been able to make himself master of the forces which, even yesterday, held him in bondage. And we cannot be too grateful to our fathers for their immense and fruitful labours, by which they succeeded in constructing the society in the midst of which we live. It is still wretched enough, this society of ours, afflicted with crimes and horrors, the infamy of which we understand full well; but however wretched it may be, it is a thousand times less wretched than was society of yore. Therefore, this formal conclusion may at once be deduced; we must do for our descendants what our fathers did for us. We would be without excuse if we rested content to benefit from the works of our predecessors without ourselves also creating something, without leaving, by means of our personal labours, a better lot to our descendants. The man who has not understood this supreme duty is truly unworthy of being a man. Verily, every individual, when he has arrived at the end of his life, should examine his conscience and ask himself if in the humble sphere of his action, he has not, even he also, contributed a stone to the human edifice, if he has not done his share in promoting and increasing the forces of humanity. Since matters stand thus, since the development of Science is the fundamental condition of the happiness of man, we must resolutely put Science at the basis of every civilisation. Alas! it has not been so up to the present; and if we study the development of human societies, we see that they are above all things attracted to war. Science has had only the leavings. But the time has come when man should no longer believe that the principle of morality is man's struggle against man. That was the history of bye-gone times. The history of to-day, and especially the history of to-morrow, is the struggle of man against matter, the subjection of natural forces to our intelligence. And there is no other way to subjugate these forces than by learning to know them. Then Science will be put in the foreground. And without making any classification which distinguishes between the sciences, which are all useful, beautiful, and noble, for all contain a portion of truth, we shall be permitted to say that the Science of life is one of the most useful, the most noble, and the most beautiful.