With many thanks, my dear sir, Yours sincerely, CH. DARWIN.
P.S.--I send by this post my paper on climbing plants, parts of which you might like to read.
[Sir Thomas Farrer and Dr. W. Ogle were also guided and encouraged by my father in their observations. The following refers to a paper by Sir Thomas Farrer, in the "Annals and Magazine of Natural History," 1868, on the fertilisation of the Scarlet Runner:]
CHARLES DARWIN TO T.H. FARRER. Down, September 15, 1868.
My dear Mr. Farrer,
I grieve to say that the MAIN features of your case are known. I am the sinner and described them some ten years ago. But I overlooked many details, as the appendage to the single stamen, and several other points. I send my notes, but I must beg for their return, as I have NO OTHER COPY. I quite agree, the facts are most striking, especially as you put them. Are you sure that the Hive-bee is the cutter? it is against my experience. If sure, make the point more prominent, or if not sure, erase it. I do not think the subject is quite new enough for the Linnean Society; but I dare say the "Annals and Magazine of Natural History," or "Gardeners" Chronicle" would gladly publish your observations, and it is a great pity they should be lost. If you like I would send your paper to either quarter with a note. In this case you must give a t.i.tle, and your name, and perhaps it would be well to premise your remarks with a line of reference to my paper stating that you had observed independently and more fully.
I have read my own paper over after an interval of several years, and am amused at the caution with which I put the case that the final end was for crossing distinct individuals, of which I was then as fully convinced as now, but I knew that the doctrine would shock all botanists. Now the opinion is becoming familiar.
To see penetration of pollen-tubes is not difficult, but in most cases requires some practice with dissecting under a one-tenth of an inch focal distance single lens; and just at first this will seem to you extremely difficult.
What a capital observer you are--a first-rate Naturalist has been sacrificed, or partly sacrificed to Public life.
Believe me, yours very sincerely, CH. DARWIN.
P.S.--If you come across any large Salvia, look at it--the contrivance is admirable. It went to my heart to tell a man who came here a few weeks ago with splendid drawings and MS. on Salvia, that the work had been all done in Germany. (Dr. W. Ogle, the observer of the fertilisation of Salvia here alluded to, published his results in the "Pop. Science Review," 1869. He refers both gracefully and gratefully to his relationship with my father in the introduction to his translation of Kerner"s "Flowers and their Unbidden Guests.")
[The following extract is from a letter, November 26th, 1868, to Sir Thomas Farrer, written as I learn from him, "in answer to a request for some advice as to the best modes of observation."
"In my opinion the best plan is to go on working and making copious notes, without much thought of publication, and then if the results turn out striking publish them. It is my impression, but I do not feel sure that I am right, that the best and most novel plan would be, instead of describing the means of fertilisation in particular plants, to investigate the part which certain structures play with all plants or throughout certain orders; for instance, the brush of hairs on the style, or the diadelphous condition of the stamens, in the Leguminosae, or the hairs within the corolla, etc. etc. Looking to your note, I think that this is perhaps the plan which you suggest.
"It is well to remember that Naturalists value observations far more than reasoning; therefore your conclusions should be as often as possible fortified by noticing how insects actually do the work."
In 1869, Sir Thomas Farrer corresponded with my father on the fertilisation of Pa.s.siflora and of Tacsonia. He has given me his impressions of the correspondence:--
"I had suggested that the elaborate series of chevaux-de-frise, by which the nectary of the common Pa.s.siflora is guarded, were specially calculated to protect the flower from the stiff-beaked humming birds which would not fertilise it, and to facilitate the access of the little proboscis of the humble bee, which would do so; whilst, on the other hand, the long pendent tube and flexible valve-like corona which retains the nectar of Tacsonia would shut out the bee, which would not, and admit the humming bird which would, fertilise that flower. The suggestion is very possibly worthless, and could only be verified or refuted by examination of flowers in the countries where they grow naturally... What interested me was to see that on this as on almost any other point of detailed observation, Mr. Darwin could always say, "Yes; but at one time I made some observations myself on this particular point; and I think you will find, etc. etc." That he should after years of interval remember that he had noticed the peculiar structure to which I was referring in the Pa.s.siflora princeps struck me at the time as very remarkable."
With regard to the spread of a belief in the adaptation of flowers for cross-fertilisation, my father wrote to Mr. Bentham April 22, 1868:
"Most of the criticisms which I sometimes meet with in French works against the frequency of crossing, I am certain are the result of mere ignorance. I have never hitherto found the rule to fail that when an author describes the structure of a flower as specially adapted for self-fertilisation, it is really adapted for crossing. The Fumariaceae offer a good instance of this, and Trevira.n.u.s threw this order in my teeth; but in Corydalis, Hildebrand shows how utterly false the idea of self-fertilisation is. This author"s paper on Salvia is really worth reading, and I have observed some species, and know that he is accurate."
The next letter refers to Professor Hildebrand"s paper on Corydalis, published in the "Proc. Internat. Hort. Congress," London, 1866, and in Pringsheim"s "Jahrbucher," volume v. The memoir on Salvia alluded to is contained in the previous volume of the same Journal:]
CHARLES DARWIN TO F. HILDEBRAND. (Professor of Botany at Freiburg.) Down, May 16 [1866].
My dear Sir,
The state of my health prevents my attending the Hort. Congress; but I forwarded yesterday your paper to the secretary, and if they are not overwhelmed with papers, yours will be gladly received. I have made many observations on the Fumariaceae, and convinced myself that they were adapted for insect agency; but I never observed anything nearly so curious as your most interesting facts. I hope you will repeat your experiments on the Corydalis on a larger scale, and especially on several distinct plants; for your plant might have been individually peculiar, like certain individual plants of Lobelia, etc., described by Gartner, and of Pa.s.siflora and Orchids described by Mr. Scott...
Since writing to you before, I have read your admirable memoir on Salvia, and it has interested me almost as much as when I first investigated the structure of Orchids. Your paper ill.u.s.trates several points in my "Origin of Species," especially the transition of organs.
Knowing only two or three species in the genus, I had often marvelled how one cell of the anther could have been transformed into the movable plate or spoon; and how well you show the gradations; but I am surprised that you did not more strongly insist on this point.
I shall be still more surprised if you do not ultimately come to the same belief with me, as shown by so many beautiful contrivances, that all plants require, from some unknown cause, to be occasionally fertilized by pollen from a distinct individual. With sincere respect, believe me, my dear Sir,
Yours very faithfully, CH. DARWIN.
[The following letter refers to the late Hermann Muller"s "Befruchtung der Blumen," by far the most valuable of the ma.s.s of literature originating in the "Fertilisation of Orchids." An English translation, by Prof. D"Arcy Thompson was published in 1883. My father"s "Prefatory Notice" to this work is dated February 6, 1882, and is therefore almost the last of his writings:]
CHARLES DARWIN TO H. MULLER. Down, May 5, 1873.
My dear Sir,
Owing to all sorts of interruptions and to my reading German so slowly, I have read only to page 88 of your book; but I must have the pleasure of telling you how very valuable a work it appears to me. Independently of the many original observations, which of course form the most important part, the work will be of the highest use as a means of reference to all that has been done on the subject. I am fairly astonished at the number of species of insects, the visits of which to different flowers you have recorded. You must have worked in the most indefatigable manner. About half a year ago the editor of "Nature"
suggested that it would be a grand undertaking if a number of naturalists were to do what you have already done on so large a scale with respect to the visits of insects. I have been particularly glad to read your historical sketch, for I had never before seen all the references put together. I have sometimes feared that I was in error when I said that C.K. Sprengel did not fully perceive that cross-fertilisation was the final end of the structure of flowers; but now this fear is relieved, and it is a great satisfaction to me to believe that I have aided in making his excellent book more generally known. Nothing has surprised me more than to see in your historical sketch how much I myself have done on the subject, as it never before occurred to me to think of all my papers as a whole. But I do not doubt that your generous appreciation of the labours of others has led you to over-estimate what I have done. With very sincere thanks and respect, believe me,
Yours faithfully, CHARLES DARWIN.
P.S.--I have mentioned your book to almost every one who, as far as I know, cares for the subject in England; and I have ordered a copy to be send to our Royal Society.
[The next letter, to Dr. Behrens, refers to the same subject as the last:]
CHARLES DARWIN TO W. BEHRENS. Down, August 29 [1878].
Dear Sir,
I am very much obliged to you for having sent me your "Geschichte der Bestaubungs-Theorie" (Progr. der K. Gewerbschule zu Elberfeld, 1877, 1878.), and which has interested me much. It has put some things in a new light, and has told me other things which I did not know. I heartily agree with you in your high appreciation of poor old C. Sprengel"s work; and one regrets bitterly that he did not live to see his labours thus valued. It rejoices me also to notice how highly you appreciate H.
Muller, who has always seemed to me an admirable observer and reasoner.
I am at present endeavouring to persuade an English publisher to bring out a translation of his "Befruchtung."
Lastly, permit me to thank you for your very generous remarks on my works. By placing what I have been able to do on this subject in systematic order, you have made me think more highly of my own work than I ever did before! Nevertheless, I fear that you have done me more than justice.
I remain, dear Sir, yours faithfully and obliged, CHARLES DARWIN.
[The letter which follows was called forth by Dr. Gray"s article in "Nature," to which reference has already been made, and which appeared June 4, 1874:]
CHARLES DARWIN TO ASA GRAY. Down, June 3 [1874].
My dear Gray,
I was rejoiced to see your hand-writing again in your note of the 4th, of which more anon. I was astonished to see announced about a week ago that you were going to write in "Nature" an article on me, and this morning I received an advance copy. It is the grandest thing ever written about me, especially as coming from a man like yourself. It has deeply pleased me, particularly some of your side remarks. It is a wonderful thing to me to live to see my name coupled in any fashion with that of Robert Brown. But you are a bold man, for I am sure that you will be sneered at by not a few botanists. I have never been so honoured before, and I hope it will do me good and make me try to be as careful as possible; and good heavens, how difficult accuracy is! I feel a very proud man, but I hope this won"t last...
[Fritz Muller has observed that the flowers of Hedychium are so arranged that the pollen is removed by the wings of hovering b.u.t.terflies. My father"s prediction of this observation is given in the following letter:]
CHARLES DARWIN TO H. MULLER. Down, August 7, 1876.