Eminent American writer (1809–1894) best known for his collection The Autocrat of the Breakfast Table and the much-anthologized poem “The Chambered Nautilus.” ALS signed “O. W. Holmes,” one page both sides, 4.5 x 7.25, March 31, 1872. Holmes writes to an unnamed gentleman. In part: “Accept my thanks for your kindness in sending me the two papers which I received yesterday. I have read that on the early stages of an Ascidian [related to a class of marine organisms known as sea squirts] with very great interest, as all must who have been startled by Mr. Darwin’s suggestion. The other I have not as yet had time to do justice to, as it requires study. But I must remark on the admirable sketches of the embryo…. The odd caricature they often present of various human ibecilities have often struck me, but never more than in your delineations….” Holmes earned an M.D. from Harvard, later taught anatomy there, and wrote on a variety of medical and scientific topics. His evident keen interest in marine biology is particularly significant in light of his best-known work, The Chambered Nautilus. Given Holmes’s remark on the “caricatures … of human imbecilities,” the reference to Darwin may relate to the publication of Darwin’s book The Expression of the Emotions in Man and Animals in the same year. Accompanied by a period portrait engraving. Mild handling wear, otherwise fine condition. R&R COA.