Metchnikoff's natural pessimism was growing under the influence of these painful circumstances. His conception of life was a sombre one; he said to himself that the "disharmonies" of human nature must infallibly end in a general decadence of humanity. He set forth his reflections in an article entitled _The Time for Marriage_, in which he discussed the following concrete fact: With the progress of civilisation and culture, the time for marriage recedes gradually, whereas puberty remains as early as before; the result is that the time between puberty and marriage is becoming longer and longer, and constitutes a growing period in which there is no harmony. The statistics of suicides prove that there is a close connection between them and the period of disharmonies. Whilst he worked, his wife tried to make use of her leisure: she interested herself in poor children, sketched flowers, read novels ... life flowed peacefully in spite of the underlying drama. Yet the thought that he was not fulfilling his obligations was intolerable to Metchnikoff. He thought of resigning and founding a small book-shop at Madeira in order to be independent and not obliged to leave his wife, but lack of funds made this plan impossible. In his search for new resources, he went to Teneriffe to look for a subject for an article. He met with several disappointments on this trip; yet he saw the Villa Orotava, with its celebrated giant dragon-tree, which had already then been brought down by a storm. He also visited the Caves of the Guancios, the primitive inhabitants of the Canary Islands. Having gathered the necessary observations, he hastened to return to Madeira, where months passed without bringing any change. The book-shop idea was abandoned as being impracticable and Metchnikoff had to return to Odessa, asking his sister-in-law to come to Madeira in his place. When she had arrived, he confided the two girls to Mertens and to the care of the devoted Dr. Goldschmidt, and went away conscious of the uselessness of his efforts and more deeply pessimistic than ever. When he reached Odessa, in October 1872, he found there his friend Setchénoff, whom he had previously proposed for a Physiology Lecturer's chair, and whose affection was a great comfort to him at this sad time. The correspondence between him and his wife during that period is full of an infinite tenderness, as if they felt the supreme separation coming near, and yearned to express their mutual love.