My dear Romanes,--I am most heartily glad that your lecture (just received and read) has been so eminently successful. You have indeed passed a most magnificent eulogium on me, and I wonder that you were not afraid of hearing 'Oh! oh!' or some other sign of disapprobation. Many persons think that what I have done in science has been much overrated, and I very often think so myself; but my comfort is that I have never consciously done anything to gain applause. Enough and too much about my dear self. The sole fault that I find with your lecture is that it is too short, and this is a rare fault. It strikes me as admirably clear and interesting. I meant to have remonstrated that you had not discussed sufficiently the necessity of signs for the formation of abstract ideas of any complexity, and then I came on to the discussion on deaf mutes. This latter seems to me one of the richest of all the mines, and is worth working carefully for years and very deeply. I should like to read whole chapters on this one head, and others on the minds of the higher idiots. Nothing can be better, as it seems to me, than your several lines or sources of evidence, and the manner in which you have arranged the whole subject. Your book will assuredly be worth years of hard labour, and stick to your subject. By the way, I was pleased at your discussing the selection of varying instincts or mental tendencies, for I have often been disappointed by no one ever having noticed this notion. I have just finished _La Psychologie, son présent et son avenir_, 1876, by Delbœuf (a mathematician and physicist of Belgium), in about one hundred pages; it has interested me a good deal, but why I hardly know; it is rather like Herbert Spencer; if you do not know it, and would care to see it, send me a post-card. Thank Heaven we return home on Thursday, and I shall be able to go on with my humdrum work, and that makes me forget my daily discomfort. Have you ever thought of keeping a young monkey,[16] so as to observe its mind? At a house where we have been staying there were Sir A. and Lady Hobhouse, not long ago returned from India, and she and he kept three young monkeys, and told me some curious particulars. One was that the monkey was very fond of looking through her eyeglass at objects, and moved the glass nearer and further so as to vary the focus. This struck me, as Frank's son, nearly two years old (and we think much of his intellect!), is very fond of looking through my pocket lens, and I have quite in vain endeavoured to teach him not to put the glass close down on the object, but he will always do so. Therefore I conclude that a child just under two years is inferior in intellect to a monkey. Once again I heartily congratulate you on your well-earned present and I feel assured grand future success. Yours very truly, CH. DARWIN.