Dear Sir

I thank you most sincerely for your letter which is very interesting to me. I wish I had known of these views of Hippocrates, before I had published, for they seem almost identical with mine—merely a change of terms—& an application of them to classes of facts necessarily unknown to this old philosopher.² The whole case is a good illustration of how rarely anything is new.— The notion of pangenesis has been a wonderful relief to my mind, (as it has to some few others) for during long years I could not conceive any possible explanation of inheritance, development &c &c, or understand in the least in what reproduction by seeds & buds consisted.

Hippocrates has taken the wind out of my sails, but I care very little about being forestalled. I advance the view merely as a provisional hypothesis, but with the secret expectation that sooner or later some such view will have to be admitted. I find that M^r. Herbert Spencer intended something altogether different.—³

You will have probably observed that I have made use of that capital twin-case.—⁴

With my very sincere thanks for your great kindness, I remain | Dear Sir | Yours faithfully & obliged | Charles Darwin

I do not expect that Reviewers will be so learned as you; otherwise no doubt I shall be accused of wilfully stealing Pangenesis from Hippocrates,—for this is the spirit some reviewers delight to show.—