Delighted with his discovery, he hastened to communicate it to Leuckart, who was incredulous at first but had to give way to evidence when Elie showed him all the intermediary stages. Still the German scientist was obviously annoyed that this discovery should have been made in his absence and independently from him. He proposed to the young man that they should continue researches in collaboration and publish a joint memoir. Elie accepted joyfully. In his ardour he worked too much, and fatigued his eyesight so that he was forced to limit his microscopical researches to a few hours a day, and Leuckart advised him to take a rest. It happened that Elie's brother Leo had just settled in Geneva and invited him to stay with him; Elie started to join him. The brothers had not met for a long time. Leo had been travelling and had resided in many different places. He was an extraordinarily gifted man, impulsive, brilliant, and artistic, but restless and incapable of adhering to a steady course of action; he scattered his activities and did not therefore produce all that his rich nature was capable of. He had a remarkable gift for languages; he knew not only a number of European languages but also several Oriental languages, having been in the East, where he had occupied a post of agent in navigation and commerce. He afterwards lived in Italy, took an active part in the Garibaldi movement and was wounded. A clever painter, he also had real literary talent; handsome, witty, agreeable, he was a most attractive personality. Elie had great affection for him. He found him surrounded with young men and studying a map. They were discussing the acquisition of a piece of ground in Italy in order to found a socialistic community, and Leo, who knew the country, was to choose the locality. Elie was at once made acquainted with the political questions of the day; the young scientist was unfavourably impressed, for the whole reduced itself to party questions and dogmatic discussions founded on hollow grounds. Accustomed as he already was to positive scientific methods, vague and arbitrary theories could not satisfy him. On the other hand, he was deeply impressed by the personality of the celebrated socialistic Russian writer, Herzen, who resided in Geneva at that time. The young revolutionaries considered him as too literary and too much of a theoretician; they themselves yearned for a direct-action policy. Leo Metchnikoff, however, admired him fervently. Meetings often took place in Herzen's rooms; he used to read to his guests with wonderful effect his yet unpublished manuscript _Passé et pensées_. A great and powerful figure, the superiority of his intelligence was almost crushing, while his sparkling wit and the nobility of his whole being endowed him with an incomparable and irresistible personal charm. Metchnikoff often said that no man had left a deeper impression on his life. As a politician, however, he had not the same prestige in his sight.