He worked a good deal at spiritualism for a year or two, and he never could assure himself that there was absolutely nothing in spiritualism, no unknown phenomena underlying the mass of fraud, and trickery, and vulgarity which have surrounded the so-called manifestations. He was always willing to investigate such subjects as hypnotism, thought reading, &c., and in 1880 he wrote an article for the September number of the 'Nineteenth Century.' in which he pleads for a candid and unprejudiced investigation of the facts. The article was a review of Heidenhain's "Der sogenannte thierische Magnetismus." The work on Pangenesis and on Medusæ went on through 1876, and some letters to and from Mr. Darwin are here inserted. _From C. Darwin, Esq., to G. J. Romanes._ Dear Romanes.--As you are interested in Pangenesis, and will some day, I hope, convert an 'airy nothing' into a substantial theory, therefore I send by this post an essay by Häckel, attacking 'Pan.,' and substituting a molecular hypothesis. If I understand his views rightly, he would say that with a bird which strengthened its wings by use, the formative protoplasm of the strengthened parts becomes changed, and its molecular vibrations consequently changed, and that their vibrations are transmitted throughout the whole frame of the bird. How he explains reversion to a remote ancestor I know not. Perhaps I have misunderstood him, though I have skimmed the whole with some care. He lays much stress on inheritance being a form of unconscious memory, but how far this is part of his molecular vibration I do not understand. His views make nothing clearer to me, but this may be my fault. No one, I presume, would doubt about molecular movements of some kind. His essay is clever and striking. If you read it (but you must not on my account), I should much like to hear your judgment, and you can return it at any time. We have come here for rest for me, which I much needed, and shall remain here for about ten days more, and then home to work, which is my sole pleasure in life. I hope your splendid Medusæ work and your experiments on Pan. are going on well. I heard from my son Frank yesterday that he was feverish with a cold, and could not dine with the Physiologists, which I am very sorry for, as I should have heard what they think about the new Bill.[10] I see that you are one of the secretaries to this young society. I was very much gratified by the wholly unexpected honour of being elected one of the hon. members. This mark of sympathy has pleased me to a very high degree. Believe me, yours very sincerely, CH. DARWIN. Häckel gives reference to a paper on Pan. of which I have never heard. I fear that you will have difficulty in reading my scrawl. Do you know who are the other hon. members of your Society? _From G. J. Romanes to C. Darwin._ Dunskaith, Nigg, Ross-shire, N.B.: June 1, 1876.