On his arrival in Boston Agassiz was cordially received by John A. Lowell, who, as trustee of the Lowell Institute, had extended to him the invitation which was in a large measure responsible for his coming. The course of lectures which Agassiz had planned for the Lowell Institute was entitled “The Plan of Creation.” His success was immediate. The people were eager to hear the message of the great lecturer. A second course, on “Glaciers,” was soon arranged, and in a few months Agassiz found himself the most popular lecturer in all the great Eastern cities. The subjects which he chose were always of a character which made it possible for large untrained audiences to follow him and clearly understand the points which he logically developed. His command of English was at first faulty, but he was never embarrassed, and his audiences found a peculiar charm in his foreign accent and the unusual phrases which he so frequently employed. But the blackboard was his unfailing assistant, and as he talked, his quick hand illustrated the subject with sketches so simple and so clear that the lecture could almost have been comprehended by these alone. He had left his collections behind him, but almost immediately new collections began to grow, and a new “scientific factory” was established in his house in East Boston. He always spoke of his specimens as “material for investigation,” for to Agassiz every stone and every insect held a story filled with wonder and romance which only patient study could unfold. His house, his garden, and even his pockets were filled with “material”; as an illustration may be mentioned the occasion when Agassiz, on being asked by a lady sitting beside him at a dinner-party to explain the difference between a toad and a frog, instantly produced, to the amazement of his companions, a live frog and a live toad from his pockets. It was but natural that Agassiz should find in Harvard University, the oldest and most celebrated seat of learning in the United States, the congenial atmosphere which his work required. And it is equally natural that the great University should recognize in Agassiz a master-teacher who would prove a most desirable addition to its faculty. Agassiz had already found in the United States a cordial welcome and a deep appreciation. The year 1848 marks definitely the beginning of the last phase of his life, for in this year the death of his wife in Carlsruhe and his acceptance of the chair of zoölogy and geology at Harvard led him to abandon forever his thought of some day returning to his native land.