At first this change operated less upon his ideas than upon his sensations and sentiments. Accustomed as he was to analyse his emotions, he realised the development within himself of a new sense of appreciation; less sensitive now to extreme impressions, he had become more so to ordinary ones. For instance, though less enchanted by music, and less irritated by discordant noises, he enjoyed absolute calm more fully. Now indifferent to rich food, which he formerly used to enjoy, he appreciated simple fare, bread and pure water. He did not seek for picturesque sites but took infinite pleasure in watching the growth of grass or the bursting of a bud. The first halting steps or the smile of an infant charmed and delighted him. Demanding less from life, he now appreciated it as it was, and experienced the joy of mere living. The instinct, the sense of life had been born in him. He now saw Life and Nature under a different aspect from that which they had borne for him in his youth, for he had gradually acquired more balance; he had become adapted. In their turn, his ideas evolved towards a more optimistic conception of life. His reflections, freed from the yoke of his juvenile sensitiveness, tended towards the possibility of a correction of the disharmonies of human nature through knowledge and will. This evolution had taken years. "In order to understand the meaning of life," he said, "it is necessary to live a long time, without which one finds oneself in the position of a congenitally blind man before whom the beauties of colour are spread out." * * * * * During the twenty-eight years that he lived in France, nearly all his time was devoted to the laboratory. Whilst the Institute was still in its beginning, work there was calm and collected; but, as its growing renown attracted many people, this quietude decreased considerably. Metchnikoff felt this, but could not bring himself to refuse to admit those who came; he compensated himself by peaceful Sundays and holidays. For a long time we inhabited the neighbourhood of the Institute and spent the summers at Sèvres; in 1898 we bought a small villa there with a sum of money which we inherited from an aunt. In 1905 we settled there altogether, for Metchnikoff, confined in the laboratory all day, felt the need of fresh air; the daily walk that he was obliged to take to reach the house and the absolute calm, away from the noise of the city, suited him; he even fancied that the hill on which the house was built provided him with a wholesome exercise for his heart.