Dear Romanes

As you are interested in Pangenesis & 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: & substituting a molecular hypothesis.² If I understand his views rightly, he w^d. say that with a bird which strengthened its wings by use, the formative protoplasm of the strengthened parts becomes changed, & its molecular vibrations consequently changed, & that these vibrations are transmitted throughout the whole frame of the bird & affect the sexual elements in such a manner that the wings of the offspring are developed in a like strengthened manner.— I imagine he w^d say in cases like those of L^d. Moreton’s mare that the vibrations from the protoplasm or “plasson” of the seminal fluid of the Zebra set plasson vibrating in the mare & that these vibrations continued until the hair of her second colt was formed, & which consequently became barred like that of a Zebra.³ 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 clear to me, but this may be my fault. No one I presume w^d. doubt about molecular movements of some kind. His essay is clever & striking. If you read it (but you must not on my account) I sh^d. much like to hear your judgment. & you can return it at any time.— The blue lines are Häckel’s, to call my attention.—⁴

We have come here for rest for me, which I much needed, & shall remain here for about 10 days more, & then home to work which is my sole pleasure in life.⁵ I hope your splendid Medusa-work & y^r experiments on Pang: are going on well.—⁶ I heard from my son Frank yesterday that he was feverish with a cold & could not dine with the Physiologists, which I am very sorry for as I sh^d. have heard what they think about the new bill.—⁷ I see that you are one of the Sec^s. to this young Soc^y. I was very much gratified by the wholly unexpected honour of being elected one of the Hon^y: Members.⁸ 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 Pang: of which I have never heard.⁹

I fear that you will have difficulty in reading my scrawl.—

Do you know who are the other Hon. members of your Soc^y.?