Volume Ii Part 37 (2/2)

Edition II., Volume I., pages 388-9.) Some of your Abutilons have germinated, but I have been very unfortunate with most of your seed.

You will remember having given me in a former letter an account of a very curious popular belief in regard to the subsequent progeny of a.s.ses, which have borne mules; and now I have another case almost exactly like that of Lord Morton's mare, in which it is said the shape of the hoofs in the subsequent progeny are affected. (Pangenesis will turn out true some day!) (682/5. See ”Animals and Plants,” Edition II., Volume I., page 435. For recent work on telegony see Ewart's ”Experimental Investigations on Telegony,” ”Phil. Trans. R. Soc.” 1899.

A good account of the subject is given in the ”Quarterly Review,” 1899, page 404. See also Letter 275, Volume I.)

A few months ago I received an interesting letter and paper from your brother, who has taken up a new and good line of investigation, viz., the adaptation in insects for the fertilisation of flowers.

The only scientific man I have seen for several months is Kolliker, who came here with Gunther, and whom I liked extremely.

I am working away very hard at my book on man and on s.e.xual selection, but I do not suppose I shall go to press till late in the autumn.

LETTER 683. TO F. MULLER. Down, January 1st, 1874.

No doubt I owe to your kindness two pamphlets received a few days ago, which have interested me in an extraordinary degree. (683/1. This refers to F. Muller's ”Bestaubungsversuche an Abutilon-Arten” in the ”Jenaische Zeitschr.” Volume VII., which are thus referred to by Darwin (”Cross and Self Fert.” pages 305-6): ”Fritz Muller has shown by his valuable experiments on hybrid Abutilons, that the union of brothers and sisters, parents and children, and of other near relations is highly injurious to the fertility of the offspring.” The Termite paper is in the same volume (viz., VII.) of the ”Jenaische Zeitschr.”) It is quite new to me what you show about the effects of relations.h.i.+p in hybrids--that is to say, as far as direct proof is concerned. I felt hardly any doubt on the subject, from the fact of hybrids becoming more fertile when grown in number in nursery gardens, exactly the reverse of what occurred with Gartner. (683/2. When many hybrids are grown together the pollination by near relatives is minimised.) The paper on Termites is even still more interesting, and the a.n.a.logy with cleistogene flowers is wonderful.

(683/3. On the back of his copy of Muller's paper Darwin wrote: ”There exist imperfectly developed male and female Termites, with wings much shorter than those of queen and king, which serve to continue the species if a fully developed king and queen do not after swarming (which no doubt is for an occasional cross) enter [the] nest. Curiously like cleistogamic flowers.”) The manner in which you refer to to my chapter on crossing is one of the most elegant compliments which I have ever received.

I have directed to be sent to you Belt's ”Nicaragua,” which seems to me the best Natural History book of travels ever published. Pray look to what he says about the leaf-carrying ant storing the leaves up in a minced state to generate mycelium, on which he supposes that the larvae feed. Now, could you open the stomachs of these ants and examine the contents, so as to prove or disprove this remarkable hypothesis? (683/4.

The hypothesis has been completely confirmed by the researches of Moller, a nephew of F. Muller's: see his ”Brasilische Pilzblumen”

(”Botan. Mittheilgn. aus den Tropen,” hrsg. von A.F.W. Schimper, Heft 7).)

LETTER 684. TO F. MULLER. Down, May 9th, 1877.

I have been particularly glad to receive your letter of March 25th on Pontederia, for I am now printing a small book on heterostyled plants, and on some allied subjects. I feel sure you will not object to my giving a short account of the flowers of the new species which you have sent me. I am the more anxious to do so as a writer in the United States has described a species, and seems to doubt whether it is heterostyled, for he thinks the difference in the length of the pistil depends merely on its growth! In my new book I shall use all the information and specimens which you have sent me with respect to the heterostyled plants, and your published notices.

One chapter will be devoted to cleistogamic species, and I will just notice your new gra.s.s case. My son Francis desires me to thank you much for your kindness with respect to the plants which bury their seeds.

I never fail to feel astonished, when I receive one of your letters, at the number of new facts you are continually observing. With respect to the great supposed subterranean animal, may not the belief have arisen from the natives having seen large skeletons embedded in cliffs? I remember finding on the banks of the Parana a skeleton of a Mastodon, and the Gauchos concluded that it was a borrowing animal like the Bizcacha. (684/1. On the supposed existence in Patagonia of a gigantic land-sloth, see ”Natural Science,” XIII., 1898, page 288, where Ameghino's discovery of the skin of Neomylodon listai was practically first made known, since his privately published pamphlet was not generally seen. The animal was afterwards identified with a Glossotherium, closely allied to Owen's G. Darwini, which has been named Glossotherium listai or Grypotherium domestic.u.m. For a good account of the discoveries see Smith Woodward in ”Natural Science,” XV., 1899, page 351, where the literature is given.)

LETTER 685. TO F. MULLER. Down, May 14th [1877].

I wrote to you a few days ago to thank you about Pontederia, and now I am going to ask you to add one more to the many kindnesses which you have done for me. I have made many observations on the waxy secretion on leaves which throw off water (e.g., cabbage, Tropoeolum), and I am now going to continue my observations. Does any sensitive species of Mimosa grow in your neighbourhood? If so, will you observe whether the leaflets keep shut during long-continued warm rain. I find that the leaflets open if they are continuously syringed with water at a temperature of about 19 deg C., but if the water is at a temperature of 33-35 deg C., they keep shut for more than two hours, and probably longer. If the plant is continuously shaken so as to imitate wind the leaflets soon open. How is this with the native plants during a windy day? I find that some other plants--for instance, Desmodium and Ca.s.sia--when syringed with water, place their leaves so that the drops fall quickly off; the position a.s.sumed differing somewhat from that in the so-called sleep. Would you be so kind as to observe whether any [other] plants place their leaves during rain so as to shoot off the water; and if there are any such I should be very glad of a leaf or two to ascertain whether they are coated with a waxy secretion. (685/1. See Letters 737-41.)

There is another and very different subject, about which I intend to write, and should be very glad of a little information. Are earthworms (Lumbricus) common in S. Brazil (685/2. F. Muller's reply is given in ”Vegetable Mould,” page 122.), and do they throw up on the surface of the ground numerous castings or vermicular ma.s.ses such as we so commonly see in Europe? Are such castings found in the forests beneath the dead withered leaves? I am sure I can trust to your kindness to forgive me for asking you so many questions.

LETTER 686. TO F. MULLER. Down, July 24th, 1878.

Many thanks for the five kinds of seeds; all have germinated, and the Ca.s.sia seedlings have interested me much, and I daresay that I shall find something curious in the other plants. Nor have I alone profited, for Sir J. Hooker, who was here on Sunday, was very glad of some of the seeds for Kew. I am particularly obliged for the information about the earthworms. I suppose the soil in your forests is very loose, for in ground which has lately been dug in England the worms do not come to the surface, but deposit their castings in the midst of the loose soil.

I have some grand plants (and I formerly sent seeds to Kew) of the cleistogamic gra.s.s, but they show no signs of producing flowers of any kind as yet. Your case of the panicle with open flowers being sterile is parallel to that of Leersia oryzoides. I have always fancied that cross-fertilisation would perhaps make such panicles fertile. (686/1.

The meaning of this sentence is somewhat obscure. Darwin apparently implies that the perfect flowers, borne on the panicles which occasionally emerge from the sheath, might be fertile if pollinated from another individual. See ”Forms of Flowers,” page 334.)

I am working away as hard as I can at all the multifarious kinds of movements of plants, and am trying to reduce them to some simple rules, but whether I shall succeed I do not know.

I have sent the curious lepidopteron case to Mr. Meldola.

LETTER 687. F. MULLER TO CHARLES DARWIN.

(687/1. In November, 1880, on receipt of an account of a flood in Brazil from which Fritz Muller had barely escaped with his life (”Life and Letters,” III., 242); Darwin immediately wrote to Hermann Muller begging to be allowed to help in making good any loss in books or scientific instruments that his brother had sustained. It is this offer of help that is referred to in the first paragraph of the following letter: Darwin repeats the offer in Letter 690.)

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