The remaining chief occasions on which Darwin alludes to pangenesis in his published letters are quoted below; they prove his confidence in the hypothesis and the nature of the hold it had upon his mind. Later on he again wrote to Huxley on the same subject:-- “I am rather ashamed of the whole affair, but not converted to a no-belief.... It is all rubbish to speculate as I have done; yet, if I ever have strength to publish my next book, I fear I shall not resist ‘Pangenesis,’ but I assure you I will put it humbly enough. The ordinary course of development of beings, such as the Echinodermata, in which new organs are formed at quite remote spots from the analogous previous parts, seems to me extremely difficult to reconcile on any view except the free diffusion in the parent of the germs or gemmules of each separate new organ: and so in cases of alternate generation.” _To_ LYELL, _August 22nd, 1867_. “I have been particularly pleased that you have noticed Pangenesis. I do not know whether you ever had the feeling of having thought so much over a subject that you had lost all power of judging it. This is my case with Pangenesis (which is 26 or 27 years old), but I am inclined to think that if it be admitted as a probable hypothesis it will be a somewhat important step in Biology.” _To_ ASA GRAY, _October 16th, 1867_. “The chapter on what I call Pangenesis will be called a mad dream, and I shall be pretty well satisfied if you think it a dream worth publishing; but at the bottom of my own mind I think it contains a great truth.” _To_ HOOKER, _November 17th_ [1867]. “I shall be intensely anxious to hear what you think about Pangenesis; though I can see how fearfully imperfect, even in mere conjectural conclusions, it is; yet it has been an infinite satisfaction to me somehow to connect the various large groups of facts, which I have long considered, by an intelligible thread.” _To_ FRITZ MÜLLER, _January 30th_ [1868]. “... I should very much like to hear what you think of ‘Pangenesis,’ though I fear it will appear to _every one_ far too speculative.” _To_ HOOKER, _February 23rd_ [1868]. After expressing a fear that Pangenesis is still-born because of the difficulty with which it is understood, he says:--