However, the point is that under Virchow—more particularly under Virchow, in fact—Haeckel would be educated into the general attitude with regard to God, nature, life, and man, to which he has since devoted his whole energy. In spite of Goethe—and who would be likely to take Goethe as his guide in his twenty-first year?—the ardent young student was as yet by no means firmly seated in the saddle. He grubbed, and sought, and rejected. In his _Riddle of the Universe_ he tells us that he “defended the Christian belief in his twenty-first year in lively discussions” with his free-thinking comrades, ... “although the study of human anatomy and physiology, and the comparison of man’s frame with that of the other animals, had already greatly enfeebled my faith. I did not entirely abandon it, after bitter struggles, until my medical studies were completed, and I began to practise. I then came to understand Faust’s saying, ‘The whole sorrow of humanity oppresses me.’ I found no more of the infinite benevolence of a loving father in the hard school of life than I could see of ‘wise providence’ in the struggle for existence.” When the three terms of medical training were over, he received another impulse to his own particular interest in science. Kölliker invited him in August, 1856, to spend the two months’ holiday with him on the Riviera. It was the first Mediterranean school of zoology, though as yet only a kind of “payment on account.” On the journey he made the acquaintance of the zoological museum at Turin and its well-travelled director, Filippo de Filippi, and he saw the grandeur of the Maritime Alps on the Col di Tenda. The master, Kölliker, Heinrich Müller, Karl Kupffer (afterwards professor at Munich), and he established themselves at Nice, and fished for all sorts of creatures with the Müller-net at Villefranche. Fortunately, Müller himself happened to be visiting the Riviera at the same time, and they received a direct stimulus from him. The first result of this journey in the summer and autumn was that Haeckel secured his degree with a zoological-anatomical work, instead of with a strictly medical treatise. As he had done from Heligoland two years before, he now brought home from the Mediterranean the material for a short technical theme. He again spent the winter at Berlin to put it together. It was an histological study of the tissues of crabs, and therefore lay in the province of the articulates, an animal group, it is curious to note, which he has not entered into more fully in the course of his long and varied work as special investigator. At Nice he made a thorough study of the nerve-tubes of the spiny lobster and other available marine crustacea, and discovered several remarkable new structural features in them. At Berlin he entered upon a minute microscopic study of the common craw-fish. His dissertation for the doctorate embodied the main results of his research. It was entitled _De