His practical career began in 1832, when he was installed at Neufchatel, from which point he easily studied the Alps.  Two years later, after the ‘Poissons fossiles’ (Fossil Fishes) appeared, he visited England to lecture.  Then returning to his picturesque home, he applied himself to original investigation, and through his lectures and publications won honors and degrees.  His daring opinions, however, sometimes provoked ardent discussion and angry comment.

Agassiz’s passion for investigation frequently led him into dangers that imperiled both life and limb.  In the summer of 1841, for example, he was lowered into a deep crevasse bristling with huge stalactites of ice, to reach the heart of a glacier moving at the rate of forty feet a day.  While he was observing the blue bands on the glittering ice, he suddenly touched a well of water, and only after great difficulty made his companions understand his signal for rescue.  These Alpine experiences are well described by Mrs. Elizabeth Gary Agassiz, and also by Edouard Desors in his ‘Sejours dans les Glaciers’ (Sojourn among the Glaciers:  Neufchatel, 1844).  Interesting particulars of these glacial studies (’Etudes des Glaciers’) were soon issued, and Agassiz received many gifts from lovers of science, among whom was numbered the King of Prussia.  His zooelogical and geological investigations were continued, and important works on ‘Fossil Mollusks,’ ‘Tertiary Shells,’ and ’Living and Fossil Echinoderms’ date from this period.

He had long desired to visit America, when he realized this wish in 1846 by an arrangement with the Lowell Institute of Boston, where he gave a series of lectures, afterwards repeated in various cities.  So attractive did he find the fauna and flora of America, and so vast a field did he perceive here for his individual studies and instruction, that he returned the following year.  In 1848 the Prussian government, which had borne the expenses of his scientific mission,—­a cruise along our Atlantic coast to study its marine life,—­released him from further obligation that he might accept the chair of geology in the Lawrence Scientific School of Harvard University.  His cruises, his explorations, and his methods, combined with his attractive personality, gave him unique power as a teacher; and many of his biographers think that of all his gifts, the ability to instruct was the most conspicuous.  He needed no text-books, for he went directly to Nature, and did not believe in those technical, dry-as-dust terms which lead to nothing and which are swept away by the next generation.  Many noted American men of science remember the awakening influence of his laboratories in Charleston and Cambridge, his museum at Harvard, and his summer school at Penikese Island in Buzzard’s Bay, Massachusetts, where natural history was studied under ideal conditions.  It was here that he said to his class:—­“A laboratory of natural history is a sanctuary where nothing profane should be tolerated.”  Whittier has left a poem called “The Prayer of Agassiz,” describing