After he had collected numerous anthropological data, Metchnikoff went again to the Astrakhan steppes in order to verify and to complete his observations of the preceding year. Whilst traversing some oases where the Russians were making experiments in artificial forestry, he had the pleasant surprise of finding some Myriapoda (_Geophilus_) bearing a number of eggs. The history of the development of those creatures was still unknown--a notable lacuna in embryology. Delighted at the idea of filling it, Metchnikoff did not hesitate to undertake a long and difficult extra journey and repaired to Astrakhan, taking with him his precious material, in order to fetch the necessary apparatus for his researches. But during the long journey several eggs perished and he had to return to the oasis with a borrowed microscope to study other eggs on the spot. In spite of very difficult conditions and of the persistent weakness of his eyesight, he succeeded in filling the lacuna in the embryology of the _Geophilus_. He had at the same time collected very interesting anthropological data. His hypothesis as to the necessity of applying to anthropology the comparative methods of embryology was fully justified, for, thanks to that process, he was able to establish a definite correlation between the Mongol race and the adolescence of the Caucasian race. He presented a report on the subject to the Anthropological Society of Moscow, but, his attention being afterwards turned in other directions, he never came back to this subject. CHAPTER XV "As to thee, Hector, thou art to me as a father and a revered mother and a brother, and thou art my husband."--_The Iliad._ Studies on childhood--The family in the upper flat--Lessons in zoology--Second marriage--Private life--Visit and death of Lvovna Nevahovna--Conjugal affection. Metchnikoff's anthropological researches led him to the study of childhood, which in its turn suggested reflections on questions of Pedagogy. His eyesight was still weak and his hunger for activity very great; in order to satisfy it, he gave lessons in a Lycée and public lectures in the Odessa University. Though time was passing, Metchnikoff could not get used to his solitude; he spent his active kindness on his friends and all around him, whilst living like an ascetic and giving away all that he could spare. But nothing could quench his thirst for a family life and affectionate intimacy.