Metchnikoff was not only exceedingly gentle and courteous in his treatment of servants and employés, but he and his wife contrived on a very small income to help in a most substantial way poor neighbours and those who had met with misfortune whether they were of French or Russian nationality. They had many friends in the world of science and art, real workers and thinkers, including those who had not and those who had "arrived." With them I met and spent a long and interesting day with Rodin the sculptor and the son of Léon Tolstoï, who was working in a Paris studio. Among the pleasures which I have derived from the _Life_ are the accounts of places such as Naples and Messina, where I stayed in order to study the embryology of marine animals as Metchnikoff did; and also the appearance in these pages from time to time of old friends such as Nikolas Kleinenberg, whom Metchnikoff met at Messina in 1883. I had formed an intimate acquaintance with Kleinenberg at Jena in 1871, when he was working at his classical monograph on Hydra, and continued it at Naples in 1875. From Messina, where he became Professor in 1875, Kleinenberg sent me for publication in the _Quarterly Journal of Microscopical Science_ his valuable memoir on the embryology of a species of Earthworm, and also rare and interesting specimens of Cephalopoda. Another great and noteworthy figure about whom all zoologists are glad to learn as much as possible is Kovalevsky. Metchnikoff made his acquaintance at Naples in 1864, and they formed a close friendship for one another. Later, in 1867, they shared the Baer Prize of the Petersburg Academy for their discoveries in embryology (p. 58). In 1868 Metchnikoff had a dispute with Kovalevsky as to the origin of the nervous system of Ascidia (p. 62), concerning which he subsequently admitted that he was wrong and Kovalevsky right. There is no doubt that Kovalevsky, by his numerous important investigations of invertebrate embryology, and especially of that of Ascidia and Amphioxus, laid the foundation of _cellular_ Embryology, and the modern study of the embryology of Invertebrates. Metchnikoff's contributions were also of great value and importance (pp. 51, 52, 53, and pp. 72 and 73), though he has not so great a triumph in animal morphology to his credit as Kovalevsky's discovery of the close identities of the development of organs in Ascidia and Amphioxus. I had long cherished profound esteem for Kovalevsky when in 1896 I met him and his daughter at Wimereux with Professor Giard. He came in the autumn of that year to London, but left unexpectedly owing to some nervous fear of annoyance by the police. The great position of Kovalevsky was deliberately ignored in a German history of Zoology,[2] published just before the Great War. Metchnikoff describes Kovalevsky as a young man, small and timid, with shy but cordial manners and the clear sweet eyes of a child: he had (like Metchnikoff) for Science an absolute cult--"no sacrifice was too