The winter of 1854 was passed in Cambridge with such quiet and rest as the conditions of his life would allow. In May of that year he received an invitation to the recently established University of Zurich, in Switzerland. His acceptance was urged upon the ground of patriotism as well as on that of a liberal endowment both for the professor, and for the museum of which he was to have charge. The offer was tempting, but Agassiz was in love (the word is not too strong) with the work he had undertaken and the hopes he had formed in America. He believed that by his own efforts, combined with the enthusiasm for science which he had aroused and constantly strove to keep alive and foster in the community, he should at last succeed in founding a museum after his own heart in the United States,--a museum which should not be a mere accumulation, however vast or extensive, of objects of natural history, but should have a well-combined and clearly expressed educational value. As we shall see, neither the associations of his early life nor the most tempting scientific prizes in the gift of the old world could divert him from this settled purpose. The proposition from Zurich was not official, but came through a friend and colleague, for whom he had the deepest sympathy and admiration,--Oswald Heer. To work in his immediate neighborhood would have been in itself a temptation. TO PROFESSOR OSWALD HEER. CAMBRIDGE, January 9, 1855. MY HONORED FRIEND, How shall I make you understand why your kind letter, though it reached me some months ago, has remained till now unanswered. It concerns a decision of vital importance to my whole life, and in such a case one must not decide hastily, nor even with too exclusive regard for one's own preference in the matter. You cannot doubt that the thought of joining an institution of my native country, and thus helping to stimulate scientific progress in the land of my birth, my home, and my early friends, appeals to all I hold dear and honorable in life. On the other side I have now been eight years in America, have learned to understand the advantages of my position here, and have begun undertakings which are not yet brought to a conclusion. I am aware also how wide an influence I already exert upon this land of the future,--an influence which gains in extent and intensity with every year,--so that it becomes very difficult for me to discern clearly where I can be most useful to science. Among my privileges I must not overlook that of passing much of my time on the immediate sea-shore, where the resources for the zoologist and embryologist are inexhaustible. I have now a house distant only a few steps from an admirable locality for these studies, and can therefore pursue them uninterruptedly throughout the whole year, instead of being limited, like most naturalists, to the short summer vacations. It is true I miss the larger museums, libraries, etc., as well as the stimulus to be derived from