When he reached Petersburg, Elie hurried to the house of his friends B----, who received him with open arms; it was a great joy to him to find himself in friendly surroundings after the recent strife. Impulsive and impressionable as he was, the disagreeable incidents he had traversed made him yearn to leave Odessa, a desire which was to be promptly realised. His communications had great success at the Congress; the President even invited him to read a paper at the general meeting; but, though strongly attracted by this proposal, which would have allowed the young scientist to expose his ideas on the comparative development of the embryonic layers, he refused it, considering that that complicated question was not yet sufficiently matured. Nevertheless, the Congress had brought him into prominence and was the cause of his obtaining a Professorship of Zoology at Petersburg. Moreover, he had the additional good fortune of being given a scientific mission and went abroad to work until the autumn term. He went to Naples in the spring of 1868, thinking to find Kovalevsky there, instead of which he found a letter from his friend awaiting him. The latter had had to go to Messina for urgent embryological work and begged Elie to look after his wife and new-born child. Metchnikoff did so most willingly until he was able to send them off to Messina. He himself followed soon after, for Kovalevsky wrote him that zoological specimens and conditions of work were far better at Messina than Naples. This time, Metchnikoff undertook the study of Sponges and Echinodermata. The two friends worked unceasingly, but Elie's sight was too weak for such excessive fatigue; he was again obliged to interrupt his studies for a while, and during that period of enforced rest he felt for the first time the need of a sentimental affection in his life. He dreamed of a helpmeet who would conform with his tastes. At Petersburg he had become very fond of Professor B.'s young daughters, the eldest of whom was about thirteen years old, and he wondered if he could not train one of those little girls to become the realisation of his ideal. He was too active by nature, however, to linger very long over reveries or over a prolonged rest; he therefore undertook a short journey through Reggio and Calabria, on his way towards Naples.