. . .I have also a piece of good news to communicate, which will, I hope, lead to very favorable results for me. I think I told you when I left for Paris that my chief anxiety was lest I might not be allowed to examine, and still less to describe, the fossil fishes and their skeletons in the Museum. Knowing that Cuvier intended to write a work on this subject, I supposed that he would reserve these specimens for himself. I half thought he might, on seeing my work so far advanced, propose to me to finish it jointly with him, --but even this I hardly dared to hope. It was on this account, with the view of increasing my materials and having thereby a better chance of success with M. Cuvier, that I desired so earnestly to stop at Strasbourg and Carlsruhe, where I knew specimens were to be seen which would have a direct bearing on my aim. The result has far surpassed my expectation. I hastened to show my material to M. Cuvier the very day after my arrival. He received me with great politeness, though with a certain reserve, and immediately gave me permission to see everything in the galleries of the Museum. But as I knew that he had put together in private collections all that could be of use to himself in writing his book, and as he had never said a word to me of his plan of publication, I remained in a painful state of doubt, since the completion of his work would have destroyed all chance for the sale of mine. Last Saturday I was passing the evening there, and we were talking of science, when he desired his secretary to bring him a certain portfolio of drawings. He showed me the contents; they were drawings of fossil fishes and notes which he had taken in the British Museum and elsewhere. After looking it through with me, he said he had seen with satisfaction the manner in which I had treated this subject; that I had indeed anticipated him, since he had intended at some future time to do the same thing; but that as I had given it so much attention, and had done my work so well, he had decided to renounce his project, and to place at my disposition all the materials he had collected and all the preliminary notes he had taken. You can imagine what new ardor this has given me for my work, the more so because M. Cuvier, M. Humboldt, and several other persons of mark who are interested in it have promised to speak in my behalf to a publisher (to Levrault, who seems disposed to undertake the publication should peace be continued), and to recommend me strongly. To accomplish my end without neglecting other occupations, I work regularly at least fifteen hours a day, sometimes even an hour or two more; but I hope to reach my goal in good time.