"Am I then to go without you," he writes; "is this irrevocable? If I were to defer my departure till September would it then be possible for you to leave Rome? It would be too delightful if we could make this journey together. I wish also, before starting, to review everything that has been done of late in paleontology, zoology, and comparative anatomy, that I may, in behalf of all these sciences, take advantage of the circumstances in which I shall be placed. . .Whatever befalls me, I feel that I shall never cease to consecrate my whole energy to the study of nature; its all powerful charm has taken such possession of me that I shall always sacrifice everything to it; even the things which men usually value most." Agassiz had determined, before starting on his journey, to complete all his unfinished works, and to put in order his correspondence and collections, including the vast amount of specimens sent him for identification or for his own researches. The task of "setting his house in order" for a change which, perhaps, he dimly felt to be more momentous than it seemed, proved long and laborious. From all accounts, he performed prodigies of work, but the winter and spring passed, and the summer of 1845 found him still at his post. Humboldt writes him not without anxiety lest his determination to complete all the tasks he had undertaken, including the Nomenclator, should involve him in endless delays and perplexities. HUMBOLDT TO AGASSIZ. BERLIN, September 16, 1845. . . .Your Nomenclator frightens me with its double entries. The Milky Way must have crossed your path, for you seem to be dealing with nebulae which you are trying to resolve into stars. For pity's sake husband your strength. You treat this journey as if it were for life. As to finishing,--alas! my friend, one does not finish. Considering all that you have in your well-furnished brain beside your accumulated papers, half the contents of which you do not yourself know, your expression "aufraumen,"--to put in final order, is singularly inappropriate. There will always remain some burdensome residue,--last things not yet accounted for. I beg you, then, not to abuse your strength. Be content to finish only what seems to you nearest completion,--the most advanced of your work.