enthusiasm. The valuable treasures of the Paris museum were at his service, and the material collected for years by Cuvier for his work on fishes was freely transferred to the young naturalist. The development theory of Geoffrey, then recently advanced, was opposed by Cuvier with all the power of his science and detailed knowledge. Agassiz accepted the ideas of his master, and firmly adhered to them throughout his life, and in later years, when the development theory advanced by Darwin came into prominence, he was uncompromising in his efforts against its promulgation. Humboldt also became his firm friend and patron, aiding him materially in the publication of his work. Among his associates were Owen, Milne-Edwards, Rud. Wagner, and Johannes Müller.
In 1832, shortly after the death of Cuvier, he returned to Switzerland and became professor of natural history in the college at Neuchâtel. His labors on the fossil fishes were gradually approaching completion, the first of the five quarto volumes, “Recherches sur les poissons fossiles,” appearing in 1833 and the last in 1843. This was undoubtedly Agassiz's most important contribution to science, and forms, with Cuvier's, Valenciennes', and Johannes Müller's works, the foundation of our present knowledge of fishes. In this book one thousand species were completely, and seven hundred partially, figured and described. At Neufchâtel he gathered around him young and talented pupils, and the little city became one of the chief seats of science in Switzerland. He created the natural history museum, and was the chief founder of the scientific society, which issued the first volume of its memoirs in 1835. During the summers frequent scientific excursions were made in the Jura and the Alps. These expeditions led to his study of the glaciers, and in 1840 he published his first “Études sur les glaciers,” which gave the results of his observations during the eight preceding summers. He had erected a station on the middle of the Aar glacier at a height of 8,000 feet above the sea and twelve miles from any human habitation, and from this now celebrated Hôtel des Neufchâtelois he conducted his experiments. In 1847 he published his “Système glaciaire,” in which he thoroughly discussed the chief phenomena of glaciers and more fully developed his views on their earlier extension. In the mean while he had also devoted considerable attention to the echinoderms, and in 1836 and 1837 published special memoirs on them. His monograph on living and fossil echinoderms, published in parts, was first issued in 1839; portions of this work were prepared by Desor and by Valentin. In 1834. in 1835, and in 1840, Agassiz visited England to obtain material for his work on fossil fishes, and as a result he published monographs on the “Fossil Fishes of the Devonian System” (1844), and on the “Fishes of the London Clay” (1845).
In 1846 he came to the United States, partly to make himself familiar with the geology and natural history of this country, in fulfilment of a mission suggested to the king of Prussia by Humboldt, and partly to deliver a series of lectures on “Comparative Embryology,” at the Lowell institute, Boston, The lectures met with a most cordial reception, and by special request he delivered an additional course on glacial phenomena. He then visited New York, Philadelphia, Charleston, and other cities, in search of material for his report. In 1847 Supt. A. D. Bache placed at his disposal the use of the steamer “Bibb,” belonging to the coast survey. This led to a scientific cruise along the coast of Massachusetts, and some years later (1850-'1) to a more extended trip to the coral reefs of Florida. In this manner he became thoroughly familiar with the marine life along our shores. The liberality of this offer affording him such valuable facilities for the continuation of his studies, and the enthusiasm with which he was everywhere greeted, induced him to make the United States his home. The Prussian government released him from his scientific mission, and he accepted, in 1848, the chair of zoölogy and geology in the Lawrence scientific school at Cambridge, Mass., a professorship specially created for him by Mr. Lawrence. At Cambridge, as abroad, he attracted brilliant young men, enthusiasts in science, many of whom to-day are among the leading naturalists in this country. Of these, besides his son Alexander, may be mentioned Bickmore, Clark, Hartt, Hyatt, Lyman, Morse, Niles, Packard, Putnam, Scudder, Shaler, Stimpson, Tenney, Verrill, Wilder, and Ward. He prepared during 1848, with Dr. A. A. Gould, “Principles of Zoölogy,” a text-book for the use of schools and colleges. In the summer of the same year, with twelve of his pupils, he made an exploring expedition to Lake Superior, and the results were published in a volume entitled “Lake Superior; its Physical Characteristics,” etc. (1850).
In succeeding years he traversed the entire country, lecturing in all the larger cities and accumulating vast collections of specimens, which constituted the foundation of the natural history museum in Cambridge. From 1851 to 1854 he was professor of comparative anatomy and zoölogy in the medical college in Charleston, S. C., and during this time he studied the marine animals of the southern coast, also visiting the adjoining states; but, as the climate did not agree with him, he returned to Cambridge. In 1854 he brought to a successful termination, by the publication of a fourth volume, the “Bibliographia Zoölogiæ et Geologiæ,” which he had begun in 1848 with H. E. Strickland. This work contains a full list of all the periodicals devoted to zoölogy and geology, and an alphabetical list of authors and their works in the same departments. It was the complement of his “Nomenclator Zoölogieus,” which appeared in 1842-'46. Agassiz next began to collect material for the publication of a magnificent work to be called “Contributions to the Natural History of the United States.” In 1857 the first volume appeared, containing as an introduction his well-known “Essay on Classification,” in which the question of development was considered in a manner directly in opposition to the now generally accepted theory of descent. Of this work, projected on a gigantic scale, only four volumes ever appeared during his life; the fifth, left incomplete, was issued by his son. His attention was then turned to his collections, which had accumulated in great bulk, and, unclassified, were stored wherever available accommodation could be obtained. In June, 1859, the museum of comparative zoology was founded, with Agassiz as its curator, and until his death much of his time was devoted to the classification and arrangement of the specimens.
In 1865, his health having become somewhat impaired by constant work, he was enabled, by the liberality of Mr. Nathaniel Thayer, a Boston merchant, to visit Brazil. Here again he made great collections, which now enrich the museum at Cambridge, and a journal of his trip was published in 1867. He was appointed in 1868 n non-resident professor of natural history in Cornell university, Ithaca, N. Y., and there delivered a course of lectures. In 1871, the coast survey, having occasion to send the new war steamer “Hassler” around
