LOUIS JEAN RUDOLPH AGASSIZ, one of the most distinguished naturalists, was born at Motier, in the Canton of Freiburg, Switzerland, in 1807. After passing through the usual course of elementary learning at Biel and Lausanne, he prosecuted his studies at Zurich and Heidelberg, and lastly studied medicine at Munich. In early youth he had displayed a strong love of natural history, and at Heidelburg and Munich comparative anatomy was his favorite occupation. In Munich he became acquainted with Martius and Spix, the well-known travellers in Brazil, and when Spix died (in 1826), his collection of one hundred and sixteen species of fish collected in Brazil, was left in the care of Agassiz. Led by this work to study Ichthyology more closely, Agassiz undertook a systematic arrangement of the fresh-water fishes found in central Europe. He at the same time devoted his attention to the fossil remains of fishes, and during his stay in Paris (1831-1832), examined several private and public fossil collections. Meanwhile he had been invited to take the professorship of Natural History in Neufchatel; and while there he published Nomenclator Zoologicus, and collected the material for his Zoological Bibliography, published by the Ray Society. In 1846, Agassiz came to the United States, and was appointed to a professorship in the Lawrence Scientific School of Harvard College. In 1852, he became professor of comparative anatomy in the medical college at Charleston, South Carolina. In 1868, he became a non-resident professor of natural history at Cornell University at Ithaca, New York. He declined the offer of a chair in Paris, made him by the Emperor of the French. He published in America, "Principles of Zoology for the use of Schools and Colleges," with Mr. A.A. Gould (Boston, 1848); and "Lake Superior, its Physical Character, vegetation and Animals" (Boston, 1850); and four volumes of Contributions to the Natural History of the United States, besides a large number of papers in the memoirs of American scientific societies In 1858, he founded the Museum of Comparative Zoology at Cambridge, aided by an endowment of $50,000 by Mr. F.C. Gray, and by large private subscriptions and gifts. In 1865, he organized a scientific expedition to Brazil, under the patronage of Mr. Nathaniel Thayer, an account of which, entitled "A Journey in Brazil, by Professor and Mrs. Louis Agassiz," was afterwards published. He died at Cambridge, Massachusets, December 14th. 1873.