I like Mirbel excessively. Considering I was a perfect stranger, of whom he knew nothing, I think he took great pains to show me what I wanted to see. Sullivant’s microscope will be of the same kind as his, only better, so that he will have the means of being a second Mirbel. Examined his microscope, which is a good one, but I think not equal to the best English; got some good hints, etc.; am to call again. He is very communicative, and you missed much in not seeing so extraordinary a man. He showed me a series of drawings and engravings on which he has been long engaged, for a mémoire on the structure of roots,--splendid drawings; and he explained to me what I before could not form a clear idea about, how the curious emboîtement or thickening of the walls of cells takes place by the development of new cells within the old. He showed me what I at once recognized as the so-called gridiron-tissue which I had seen in England, and I noticed that he explained it in the same way as Brown. He promised me copies for self and friends of the late paper of his on Embryologia in the “Comptes Rendus,” just now read before the Institute (which will also be published with a part of the plates in the “Annales des Sciences Naturelles” and finally completely in “Archives du Muséum “), in which he says he has completely upset the new-fangled notions of Schleiden, Unger, etc. (adopted by Endlicher); and, what is remarkable, his investigations on the subject were made before he knew of their views, and the publication is only a little hastened on account of theirs. This evening I have been with Webb, looking up Desfontaines and Poiret plants, also some of Spach. Did I tell you I have seen a good deal of Spach of late? He does not agree well with the other botanists of the Garden; but there are some good points about him, and he is mending every day. I pushed him rather hard upon some of his bad ways, particularly that of his changing specific names, which he bore very well. Webb says he is now falling into an opposite extreme as to species, and will hardly admit anything to be distinct; but Webb himself rather inclines to multiply species, I believe. I am to meet Spach at his place in the Garden to-morrow morning. He is married, lately, to Miss Legendre, a relative of Mirbel’s, who made his drawings in Marchantia, etc.,--indeed the best botanical artiste in Paris. What a fine library Jussieu has! And what a capital advantage it is to have a great botanist for one’s father! I particularly envy Jussieu his collection of botanical pamphlets, which fill a large cabinet, all arranged in families, etc., the largest collection of the kind in the world, Jussieu thinks. He gave me to-day a little print of his father taken in the year his “Genera Plantarum” was published. He told me, what I did not know before, that Bernard de Jussieu superintended the publication of Aublet’s “Plantes de la Guiane.” I could buy that work rather cheap, but think I must refrain. I