This Institute is, however, insufficient in view of the considerable development of radioactivity and of its therapeutic applications. The best authorized persons now recognize that France must possess a Radium Institute comparable to those of England and America for the _Curietherapie_ which has become an efficacious means in the battle against cancer. It is to be hoped that with generous and far-seeing aid, we shall have, in a few years, a Radium Institute complete and enlarged, worthy of our country. To honor the memory of Pierre Curie, the French Society of Physics decided to issue a complete publication of his works. This publication, arranged by P. Langevin and C. Cheneveau, comprises but a single volume of about 600 pages, which appeared in 1908, and for which I wrote a preface. This unique volume, which includes a work as important as it is varied, is a faithful reflection of the mentality of the author. One finds in it a great richness of ideas and of experimental facts leading to clear and well-established results, but the exposition is limited to the strictly necessary, and is irreproachable, one might even say classical, in form. It is to be regretted that Pierre Curie did not use his gifts as scientist and author in writing extended memoirs or books. It was not the desire that was lacking; he had several cherished projects of this nature. But he could never put them into execution because of the difficulties with which he had to struggle during all his working life. And now, let us glance at this narrative as a whole, in which I have attempted to evoke the image of a man who, inflexibly devoted to the service of his ideal, honored humanity by an existence lived in silence, in the simple grandeur of his genius and his character. He had the faith of those who open new ways. He knew that he had a high mission to fulfil and the mystic dream of his youth pushed him invincibly beyond the usual path of life into a way which he called anti-natural because it signified the renunciation of the pleasures of life. Nevertheless, he resolutely subordinated his thoughts and desires to this dream, adapting himself to it and identifying himself with it more and more completely. Believing only in the pacific might of science and of reason, he lived for the search of truth. Without prejudice or _parti pris_, he carried the same loyalty into his study of things that he used in his understanding of other men and of himself. Detached from every common passion, seeking neither supremacy nor honors, he had no enemies, even though the effort he had achieved in the control of himself had made of him one of those elect whom we find in advance of their time in all the epochs of civilization. Like them he was able to exercise a profound influence merely by the radiation of his inner strength.