Life and Letters of Charles Darwin Volume II Part 57

[An extract from a letter to Dr. Gray (March 11, 1873) mentions the progress of the work:--

"I worked last summer hard at Drosera, but could not finish till I got fresh plants, and consequently took up the effects of crossing and sel-fertilising plants, and am got so interested that Drosera must go to the dogs till I finish with this, and get it published; but then I will resume my beloved Drosera, and I heartily apologise for having sent the precious little things even for a moment to the dogs."

The following letters give the author's impression of his own book.]

CHARLES DARWIN TO J. MURRAY. Down, September 16, 1876.

My dear Sir,

I have just received proofs in sheet of five sheets, so you will have to decide soon how many copies will have to be struck off. I do not know what to advise. The greater part of the book is extremely dry, and the whole on a special subject. Nevertheless, I am convinced that the book is of value, and I am convinced that for MANY years copies will be occasionally sold. Judging from the sale of my former books, and from supposing that some persons will purchase it to complete the set of my works, I would suggest 1500. But you must be guided by your larger experience. I will only repeat that I am convinced the book is of some permanent value...

CHARLES DARWIN TO VICTOR CARUS. Down, September 27, 1876.

My dear Sir,

I sent by this morning's post the four first perfect sheets of my new book, the t.i.tle of which you will see on the first page, and which will be published early in November.

I am sorry to say that it is only shorter by a few pages than my 'Insectivorous Plants.' The whole is now in type, though I have corrected finally only half the volume. You will, therefore, rapidly receive the remainder. The book is very dull. Chapters II. to VI., inclusive, are simply a record of experiments. Nevertheless, I believe (though a man can never judge his own books) that the book is valuable.

You will have to decide whether it is worth translating. I hope so. It has cost me very great labour, and the results seem to me remarkable and well established.

If you translate it, you could easily get aid for Chapters II. to VI., as there is here endless, but I have thought necessary repet.i.tion. I shall be anxious to hear what you decide...

I most sincerely hope that your health has been fairly good this summer.

My dear Sir, yours very truly, CH. DARWIN.

CHARLES DARWIN TO ASA GRAY. Down, October 28, 1876.

My dear Gray,

I send by this post all the clean sheets as yet printed, and I hope to send the remainder within a fortnight. Please observe that the first six chapters are not readable, and the six last very dull. Still I believe that the results are valuable. If you review the book, I shall be very curious to see what you think of it, for I care more for your judgment than for that of almost any one else. I know also that you will speak the truth, whether you approve or disapprove. Very few will take the trouble to read the book, and I do not expect you to read the whole, but I hope you will read the latter chapters.

... I am so sick of correcting the press and licking my horrid bad style into intelligible English.

[The 'Effects of Cross and Self-fertilisation' was published on November 10, 1876, and 1500 copies were sold before the end of the year. The following letter refers to a review in 'Nature' (February 15, 1877.):]

CHARLES DARWIN TO W. THISELTON DYER. Down, February 16, 1877.

Dear Dyer,

I must tell you how greatly I am pleased and honoured by your article in 'Nature,' which I have just read. You are an adept in saying what will please an author, not that I suppose you wrote with this express intention. I should be very well contented to deserve a fraction of your praise. I have also been much interested, and this is better than mere pleasure, by your argument about the separation of the s.e.xes. I dare say that I am wrong, and will hereafter consider what you say more carefully: but at present I cannot drive out of my head that the s.e.xes must have originated from two individuals, slightly different, which conjugated. But I am aware that some cases of conjugation are opposed to any such views.

With hearty thanks, Yours sincerely, CHARLES DARWIN.

CHAPTER 2.XII. -- 'DIFFERENT FORMS OF FLOWERS ON PLANTS OF THE SAME SPECIES.'

1877.

[The volume bearing the above t.i.tle was published in 1877, and was dedicated by the author to Professor Asa Gray, "as a small tribute of respect and affection." It consists of certain earlier papers re-edited, with the addition of a quant.i.ty of new matter. The subjects treated in the book are:--

1. Heterostyled Plants.

2. Polygamous, Dioecious, and Gynodioecious Plants.

3. Cleistogamic Flowers.

The nature of heterostyled plants may be ill.u.s.trated in the primrose, one of the best known examples of the cla.s.s. If a number of primroses be gathered, it will be found that some plants yield nothing but "pin-eyed"

flowers, in which the style (or organ for the transmission of the pollen to the ovule) is long, while the others yield only "thrum-eyed" flowers with short styles. Thus primroses are divided into two sets or castes differing structurally from each other. My father showed that they also differ s.e.xually, and that in fact the bond between the two castes more nearly resembles that between separate s.e.xes than any other known relations.h.i.+p. Thus for example a long-styled primrose, though it can be fertilised by its own pollen, is not FULLY fertile unless it is impregnated by the pollen of a short-styled flower. Heterostyled plants are comparable to hermaphrodite animals, such as snails, which require the concourse of two individuals, although each possesses both the s.e.xual elements. The difference is that in the case of the primrose it is PERFECT FERTILITY, and not simply FERTILITY, that depends on the mutual action of the two sets of individuals.

The work on heterostyled plants has a special bearing, to which the author attached much importance, on the problem of origin of species.

(See 'Autobiography,' volume i.)

He found that a wonderfully close parallelism exists between hybridisation and certain forms of fertilisation among heterostyled plants. So that it is hardly an exaggeration to say that the "illegitimately" reared seedlings are hybrids, although both their parents belong to identically the same species. In a letter to Professor Huxley, my father writes as if his researches on heterostyled plants tended to make him believe that sterility is a selected or acquired quality. But in his later publications, e.g. in the sixth edition of the 'Origin,' he adheres to the belief that sterility is an incidental rather than a selected quality. The result of his work on heterostyled plants is of importance as showing that sterility is no test of specific distinctness, and that it depends on differentiation of the s.e.xual elements which is independent of any racial difference. I imagine that it was his instinctive love of making out a difficulty which to a great extent kept him at work so patiently on the heterostyled plants. But it was the fact that general conclusions of the above character could be drawn from his results which made him think his results worthy of publication. (See 'Forms of Flowers,' page 243.)

The papers which on this subject preceded and contributed to 'Forms of Flowers' were the following:--

"On the two Forms or Dimorphic Condition in the Species of Primula, and on their remarkable s.e.xual Relations." Linn. Soc. Journal, 1862.)

"On the Existence of Two Forms, and on their Reciprocal s.e.xual Relations, in several Species of the Genus Linum." Linn. Soc. Journal, 1863.

"On the s.e.xual Relations of the Three Forms of Lythrum salicaria," Ibid.

1864.

"On the Character and Hybrid-like Nature of the Offspring from the Illegitimate Unions of Dimorphic and Trimorphic Plants." Ibid. 1869.

"On the Specific Differences between Primula veris, Brit. Fl. (var.

Officinalis, Linn.), P. vulgaris, Brit. Fl. (var. acaulis, Linn.) and P. elatior, Jacq.; and on the Hybrid Nature of the Common Oxlip.

With Supplementary Remarks on Naturally Produced Hybrids in the Genus Verbasc.u.m." Ibid. 1869.

The following letter shows that he began the work on heterostyled plants with an erroneous view as to the meaning of the facts.]

CHARLES DARWIN TO J.D. HOOKER. Down, May 7 [1860].

... I have this morning been looking at my experimental cowslips, and I find some plants have all flowers with long stamens and short pistils, which I will call "male plants," others with short stamens and long pistils, which I will call "female plants." This I have somewhere seen noticed, I think by Henslow; but I find (after looking at my two sets of plants) that the stigmas of the male and female are of slightly different shape, and certainly different degree of roughness, and what has astonished me, the pollen of the so-called female plant, though very abundant, is more transparent, and each granule is exactly only 2/3 of the size of the pollen of the so-called male plant. Has this been observed? I cannot help suspecting [that] the cowslip is in fact dioecious, but it may turn out all a blunder, but anyhow I will mark with sticks the so-called male and female plants and watch their seeding. It would be a fine case of gradation between an hermaphrodite and unis.e.xual condition. Likewise a sort of case of balancement of long and short pistils and stamens. Likewise perhaps throws light on oxlips...

I have now examined primroses and find exactly the same difference in the size of the pollen, correlated with the same difference in the length of the style and roughness of the stigmas.