He wrote to Sir J.D. Hooker, "I am glad that you approve of the 'Worms.' When in old days I used to tell you whatever I was doing, if you were at all interested, I always felt as most men do when their work is finally published."
To Mr. Mellard Reade he wrote (November 8): "It has been a complete surprise to me how many persons have cared for the subject." And to Mr. Dyer (in November): "My book has been received with almost laughable enthusiasm, and 3500 copies have been sold!!!" Again, to his friend Mr. Anthony Rich, he wrote on February 4, 1882, "I have been plagued with an endless stream of letters on the subject; most of them very foolish and enthusiastic; but some containing good facts which I have used in correcting yesterday the 'Sixth Thousand.'" The popularity of the book may be roughly estimated by the fact that, in the three years following its publication, 8500 copies were sold--a sale relatively greater than that of the 'Origin of Species.'
It is not difficult to account for its success with the non-scientific public. Conclusions so wide and so novel, and so easily understood, drawn from the study of creatures so familiar, and treated with unabated vigour and freshness, may well have attracted many readers. A reviewer remarks: "In the eyes of most men...the earthworm is a mere blind, dumb, senseless, and unpleasantly slimy annelid. Mr. Darwin undertakes to rehabilitate his character, and the earthworm steps forth at once as an intelligent and beneficent personage, a worker of vast geological changes, a planer down of mountain sides...a friend of man...and an ally of the Society for the preservation of ancient monuments." The "St. James Gazette", October 17, 1881, pointed out that the teaching of the cumulative importance of the infinitely little is the point of contact between this book and the author's previous work.
One more book remains to be noticed, the 'Life of Erasmus Darwin.'
In February 1879 an essay by Dr. Ernst Krause, on the scientific work of Erasmus Darwin, appeared in the evolutionary journal, 'Kosmos.' The number of 'Kosmos' in question was a "Gratulationsheft" (The same number contains a good biographical sketch of my father, of which the material was to a large extent supplied by him to the writer, Professor Preyer of Jena. The article contains an excellent list of my father's publications.), or special congratulatory issue in honour of my father's birthday, so that Dr. Krause's essay, glorifying the older evolutionist, was quite in its place. He wrote to Dr. Krause, thanking him cordially for the honour paid to Erasmus, and asking his permission to publish (The wish to do so was shared by his brother, Erasmus Darwin the younger, who continued to be associated with the project.) an English translation of the Essay.
His chief reason for writing a notice of his grandfather's life was "to contradict flatly some calumnies by Miss Seward." This appears from a letter of March 27, 1879, to his cousin Reginald Darwin, in which he asks for any documents and letters which might throw light on the character of Erasmus. This led to Mr. Reginald Darwin placing in my father's hands a quantity of valuable material, including a curious folio common-place book, of which he wrote: "I have been deeply interested by the great book,...reading and looking at it is like having communion with the dead...[it] has taught me a good deal about the occupations and tastes of our grandfather." A subsequent letter (April 8) to the same correspondent describes the source of a further supply of material:--
Since my last letter I have made a strange discovery; for an old box from my father marked "Old Deeds," and which consequently I had never opened, I found full of letters--hundreds from Dr. Erasmus--and others from old members of the Family: some few very curious. Also a drawing of Elston before it was altered, about 1750, of which I think I will give a copy."
Dr. Krause's contribution formed the second part of the 'Life of Erasmus Darwin,' my father supplying a "preliminary notice." This expression on the title-page is somewhat misleading; my father's contribution is more than half the book, and should have been described as a biography.