His dreams were at last realised. This is from a narration of the causes which led to his departure from Russia, in his own words:
Thus it was in Paris that I succeeded at last in practising pure Science apart from all politics or any public function. That dream could not have been realised in Russia because of obstacles from above, from below, and from all sides. One might think that the hour of science in Russia has not yet struck. I do not believe that. I think, on the contrary, that scientific work is indispensable to Russia, and I wish from my heart that future conditions may become more favourable than in the time of which I have spoken in the above lines.
Soon he was able to appreciate the great French qualities: humanitarian manners, tolerance, and gentleness, real freedom of thought, loyal and courteous intercourse, all of which made life easy and agreeable. And most precious of all were the true friendships which he contracted with his colleagues and his pupils. Indeed the Institut Pasteur and France became for him a second Motherland, and when in later years he was invited to other countries with more liberal conditions, he habitually replied that only for one place would he leave the Pasteur Institute, “the neighbouring cemetery of Montparnasse.”
However, after his death, the Pasteur Institute which he had so loved continued to give him hospitality and harboured his ashes....
Pasteur himself ever was most kind and helpful to Metchnikoff. During the first years, when his health still allowed it, he used often to come to the laboratory, questioning Metchnikoff on his researches with much interest and always warmly encouraging him. He even attended assiduously his course of lectures on inflammation. After his state of health no longer allowed him to go out, Metchnikoff used to visit him every day, and tried to cheer him by talking to him of current researches.
MM. Duclaux and Roux became his closest friends; they were at first brought together by scientific interests and by questions concerning the Institute; but, gradually, personal sympathy grew up between them, binding them by that solid bond which is made up of daily occurrences, inducing respect, confidence, and affection. Moreover, Metchnikoff felt the deepest gratitude towards Pasteur and his collaborators, who had given him the possibility of working in so favourable an atmosphere.
From the very first, Pasteur sympathised with the phagocyte theory; the other members of the Institute thought it too biological, almost vitalistic. But when they had made themselves thoroughly cognisant with it, they also adopted it. Thus, having found in the Pasteur Institute not only favourable working conditions but also moral support, Metchnikoff became deeply attached to it, and the interests of “the House” became his.
In 1915, on the occasion of Metchnikoff’s seventieth anniversary, M. Roux, in a Jubilee speech, gave of him and of his work the following appreciation which describes, better than anything I could say, what his part was in the Pasteur Institute: