return to them entirely until he got to Messina, where he devoted himself to the radiolaria, which were destined to play so important a part in his work. Darwin, who was soon to dominate his whole thought, had little significance for him at that time, as the struggle for life had not yet been discovered. We rarely spoke of it, but talked constantly of Johannes Müller. He was Haeckel’s ideal, as long as I kept in touch with him. He also spoke often and generously of his university friends, Dr. W. D. Focke, who was his special botanical comrade, Dr. Dreyer and Dr. Strube, who were his chief friends at the university at Würtzburg. The ordinary life and pleasures of the student, and their heavy beer-drinking, were a torture to him; he avoided them as much as possible. Very often I could not understand how it was that I brought him to the highest pitch of gaiety, whereas on all his earlier travels, especially when botany was still his favourite science, he would, after the common meal, withdraw quietly with his books and plants to the solitude of his own room. Yet he could be the gayest of all. In fact, his hearty and wonderful laugh, in all notes up to the very highest, rings over and over again in the memory of any man who has once heard it; it is the frank laughter of a glad human heart. And whoever has seen the deep earnestness with which the great scientist threw himself into the study of the most arduous problems would be astounded to hear it.” * * * * *