When Darwin's work appeared in 1859, and fell like a flash of lightning on the dark world of official biology, I was engaged in a scientific expedition to Sicily and taken up with a thorough study of the graceful radiolarians, those wonderful microscopic marine animals that surpass all other organisms in the beauty and variety of their forms. The special study of this remarkable class of animals, of which I afterwards described more than 4,000 species, after more than ten years of research, provided me with one of the solid foundation-stones of my Darwinian ideas. But when I returned from Messina to Berlin in the spring of 1860, I knew nothing as yet of Darwin's achievement. I merely heard from my friends at Berlin that a remarkable work by a crazy Englishman had attracted great attention, and that it turned upside down all previous ideas as to the origin of species. I soon perceived that almost all the experts at Berlin--chief amongst them were the famous microscopist, Ehrenberg; the anatomist, Reichert; the zoologist, Peters; and the geologist, Beyrich--were unanimous in their condemnation of Darwin. The brilliant orator of the Berlin Academy, Emil du Bois-Reymond, hesitated. He recognised that the theory of evolution was the only natural solution of the problem of creation; but he laughed at the application of it as a poor romance, and declared that the phylogenetic inquiries into the relationship of the various species had about as much value as the research of philologists into the genealogical tree of the Homeric heroes. The distinguished botanist, Alexander Braun, stood quite alone in his full and warm assent to the theory of evolution. I found comfort and encouragement with this dear and respected teacher, when I was deeply moved by the first reading of Darwin's book, and soon completely converted to his views. In Darwin's great and harmonious conception of Nature, and his convincing establishment of evolution, I had an answer to all the doubts that had beset me since the beginning of my biological studies.