Darwin had strengthened his book with a large amount of the best material that zoology and botany could supply. But there was something else to be done: a theoretical treatment of a general character with cleverly grouped illustrations from the facts already provided by two sciences, and to reconstruct these sciences from their foundations on the basis of the new theory. At that time Haeckel was doing an incredible amount of work, with body and mind. He had an iron constitution. In the year of the Stettin speech he won a laurel crown at the Leipsic athletic festival for the long jump, with a leap of twenty feet. His physical strength seemed so inexhaustible that his host, Engelmann, put a pair of heavy iron dumb-bells in his bed, in case he should want to take exercise during the night. He had a proportionate strength of mind. Everything seemed to promise very well for the next few years, so that he could devote his whole health and strength to the great task of his life. His teaching did not give him very much trouble in a small university like Jena, that was only just beginning to have a scientific name. The happiness of his home life, with a highly gifted woman who shared all his ideas with the freshness of youth, began to chain the restless wanderer with pleasant bonds to his place. He, of course, expected to have his sea-holiday in the old way for the study of his little marine treasures, but otherwise he remained quietly in the valley of the Saale. The warmth of genial and most stimulating friendships gathered about his life. With his comfortable material position he set to work on his great task under the best auspices. He would have had at the start material enough to work upon without Darwin. From Müller’s time he still had another special class of material, similar to the radiolaria, the medusæ.