I really have no criticism to make. (148/2. Mr. Bates' paper on mimetic butterflies was read before the Linnean Society, November 21st, 1861, and published in the "Linn. Soc. Trans." XXIII., 1862, page 495, under the title of "Contributions to an Insect Fauna of the Amazon Valley.") Style seems to me very good and clear; but I much regret that in the title or opening passage you did not blow a loud trumpet about what you were going to show. Perhaps the paper would have been better more divided into sections with headings. Perhaps you might have given somewhere rather more of a summary on the progress of segregation of varieties, and not referred your readers to the descriptive part, excepting such readers as wanted minute detail. But these are trifles: I consider your paper as a most admirable production in every way. Whenever I come to variation under natural conditions (my head for months has been exclusively occupied with domestic varieties), I shall have to study and re-study your paper, and no doubt shall then have to plague you with questions. I am heartily glad to hear that you are well. I have been compelled to write in a hurry; so excuse me. LETTER 149. TO T.H. HUXLEY. Down, December 7th [1862]. I was on the point of adding to an order to Williams & Norgate for your Lectures (149/1. "A Course of Six Lectures to Working Men," published in six pamphlets by Hardwicke, and later as a book. See Letter 156.) when they arrived, and much obliged I am. I have read them with interest, and they seem to me very good for this purpose and capitally written, as is everything which you write. I suppose every book nowadays requires some pushing, so that if you do not wish these lectures to be extensively circulated, I suppose they will not; otherwise I should think they would do good and spread a taste for the natural sciences. Anyhow, I have liked them; but I get more and more, I am sorry to say, to care for nothing but Natural History; and chiefly, as you once said, for the mere species question. I think I liked No. III. the best of all. I have often said and thought that the process of scientific discovery was identical with everyday thought, only with more care; but I never succeeded in putting the case to myself with one-tenth of the clearness with which you have done. I think your second geological section will puzzle your non-scientific readers; anyhow, it has puzzled me, and with the strong middle line, which must represent either a line of stratification or some great mineralogical change, I cannot conceive how your statement can hold good. I am very glad to hear of your "three-year-old" vigour [?]; but I fear, with all your multifarious work, that your book on Man will necessarily be delayed. You bad man; you say not a word about Mrs. Huxley, of whom my wife and self are always truly anxious to hear.