Insectivorous Plants.

London: John Murray, 1875.

First edition, presentation copy, of Darwin’s treatise on carnivorous plants. After conducting some early experiments on Drosera, or the common sundew, in 1860, Darwin resumed a serious interest in insect-catching plants in 1872. Desmond and Moore (Darwin, p. 597) paint an amusing picture of him busily amassing “fly-traps, bladderworts and butterworts” who were “wined, dined, and poisoned. They arrived from around the world to be held on remand in the garden hot-house. They presented a rogues’ gallery in their pots, displaying every devious means of gluing, trapping and drowning their prey. As the experiments proceeded he began writing Insectivorous Plants. Inevitably the strain proved too much.” “Darwin was helped by various physiologists and chemists in the experimental work, particularly by Professor Edward Frankland of the Royal College of Chemistry. His sons helped with the illustrations, George doing those for Drosera and Dionaea and Francis those for Aldrovanda and Utricularia. He himself was no draughtsman, but text figures 7 and 8 were cut from his drawings” (Freeman). Darwin also corresponded with the New Jersey naturalist Mary Treat about carnivorous plants, exchanging 15 letters with her from 1871-76. Darwin wrote of Insectivorous Plants in his autobiography:During subsequent years, whenever I had leisure, I pursued my experiments, and my book on Insectivorous Plants was published July 1875,—that is sixteen years after my first observations. The delay in this case, as with all my other books, has been a great advantage to me; for a man after a long interval can criticise his own work, almost as well as if it were that of another person.” In the opening paragraph, Darwin recounted the surprise he felt that summer day in 1860 at “how large a number of insects were caught by the leaves of the common sun-dew.” Collecting a dozen plants at random, he found 31 dead insects or insect remnants adhering to 56 fully expanded leaves. Taking into account how common the sun-dew is in some regions, he realized that “the number of insects thus annually slaughtered must be prodigious.” What “advantage” does the sun-dew derive from this slaughter? His subsequent investigations led to “highly remarkable” results, which he presented in Insectivorous Plants.

Provenance: presentation inscription in Murray’s clerk’s hand on half-title; Alfred W. Bennett (signature in pencil on half-title). Alfred William Bennett (1833-1902) was best known for his work on the flora of the Swiss Alps, cryptogams, and the Polygalaceae or Milkwort plant family, as well as his years in the publishing industry. He was editor of the Journal of the Royal Microscopical Society, the main publication of the Society, an institution in which he was a fellow and also served three terms as vice-president.

Plants and flowers offered an endless source of inspiration for Charles Darwin, even more so, it seems at times, than animals, as comments in many letters to his friends attest. Botanical study and correspondence also comforted the naturalist in some of his darkest hours. Charles and his wife, Emma, turned to their little daughter Annie’s flower garden to comfort them during the illness that killed her.Likewise, he began his early studies of carnivorous plants in the long shadow of his daughter Henrietta’s poor health. To read Darwin’s plant books … is to see a man deeply infatuated by the object of his inquiry, and his descriptions of a multitude of plants are replete with loaded, emotional terms. Plants, on Darwin’s view, were not passive objects suffering quietly metaphorical transformations into queen or criminal, but rather they were active participants in the drama of evolution. He saw them as creatures with ‘sensibility,’ possessing objectives, desires, and even feelings, and envisioned them as performing goal-oriented actions ‘in manifest relation to their wants.’ For instance, when the leaves of Drosera, which Darwin considered ‘first rate chemists,’ encountered ‘a bit of dry moss or peat . . . its tentacles clasp it in a useless manner’ before they ‘discover their mistake and release such innutritious objects.’

“Clearly, as even a cursory review of Darwin’s writings can attest, few organisms, if any, were beneath his interest. But what made the ‘humble sundew’ take such a hold of his imagination? The naturalist’s correspondence with friends and fellow botanists displays his intense enthusiasm for the subject, writing often about his progress with his ‘beloved Drosera’ and chastising himself for those times when absorption in other work caused him to send ‘the precious little things even for a moment to the dogs.’ These letters also reveal something about the fundamentally unsettling nature of these plants. Early in his study of the plant, he confessed to his friend the geologist Charles Lyell his feeling about ‘that wicked dear little Drosera’: ‘I will & must finish my Drosera M.S. which will take me a week, for at this present moment I care more about Drosera than the origin of all the species in the world. But I will not publish on Drosera till next year, for I am frightened and astounded by my results.’ Writing to his American friend the botanist Asa Gray, Darwin again acknowledged that he flinched at the implications of his results, explaining: ‘I have gone on working at Drosera, but shall not publish till next summer, as I am frightened by my results & must retest them.’ Darwin does not explain the source of his fear, but clues and suggestions can be garnered elsewhere in the letter. To begin with, Darwin, while commenting on Gray’s influential review of Origin, states for perhaps the first time to his friend that he ‘cannot honestly go as far as you do about Design.’ He argues further that, unlike Gray, he cannot accept ‘that variation has been led along certain beneficial lines.’ Perhaps, as he wrote this, he was thinking about the ‘baited trap’ of his Drosera, ‘excellently adapted for the special purpose of catching insects,’ which resulted in what is often represented in Insectivorous Plants as a slow and torturous death for the captured prey.

“When Darwin began his investigation into the Drosera, he understood little about the plant’s physiology—and he was not alone. Joseph Hooker, an eminent botanist and an intimate friend of Darwin, notes in his account of these ‘brother-organisms’ that while many scientists had accurately described the ‘habits’ of carnivorous plants, ‘few inquired into their motives.’ Until Darwin came along, that is. It was Darwin’s intimate understanding of the complex relationship between an organism and its environment that ultimately enabled him to unravel the mystery at the heart of the sundew, and indeed all insectivorous plants. Darwin proved conclusively that these plants, which inhabit boggy, nutrient-poor areas, compensated for nutritional deficiencies by transferring responsibility for the uptake of nutrients from the roots, where it typically resides, to the leaves. In order to accomplish this task, the plant’s leaves adapted to trap insects, secrete digestive fluids, and ingest the nitrogen-rich proteins of the insects’ bodies. Insects are often the preferred meal, especially in the plants’ natural habitats, but, as Darwin’s and Mary Treat’s experiments proved, they also ingested animal meat. In the process of detailing plant carnivory, Darwin also neatly argued a case for ‘parallel evolution’ by proving that carnivorous ‘habits’ developed in distinct groups of plants ‘in response to a common driving force.’ He patiently recorded the numbers of flies, gnats, spiders, and other insects captured and consumed by species of Drosera, Dionaea, Sarracenia, Utricularia, and others. They, in turn, were subjected to countless irritants (camel hair brushes, paper strips, pieces of hair, bits of cinder, clear glass, blue glass, sand—virtually anything that came to hand). Darwin meticulously catalogued each response, and the accrued details resulted in an astoundingly complete portrait of a seemingly sentient creature.

“Darwin published the results of his studies, not in 1861, as he anticipated in his letter to Lyell, but, in true Darwinian form, fourteen years later in 1875 after compiling exhaustive data on the subject. Insectivorous Plants thus details Darwin’s attempts to understand the ‘motives’ of carnivorous plants, namely their ‘remarkable’ ability to process nitrogen from living organisms in much the same way as humans do, by employing digestive acids analogous to the enzyme pepsin, which is found in animal stomachs. As he explains: ‘Finally, the experiments recorded in this chapter show us that there is a remarkable accordance in the power of digestion between the gastric juice of animals with its pepsin and hydrochloric acid and the secretion of Drosera with its ferment and acid belonging to the acetic series. We can, therefore, hardly doubt that the ferment in both cases is closely similar, if not identically the same. That a plant and an animal should pour forth the same, or nearly the same, complex secretion, adapted for the same purpose of digestion, is a new and wonderful fact in physiology.’

“Although Darwin insists that plants do not possess anything akin to a brain, or ‘a central organ, able to receive impressions from all points, to transmit their effects in any definite direction, to store them up and reproduce them,’ he nevertheless marvels that the leaves of the Drosera are able ‘to transmit a motor impulse to a distant point, inducing movement.’ ‘With Drosera,’ he explains, ‘the really marvellous fact is, that a plant without any specialised nervous system should be affected by such minute particles; but we have no grounds for assuming that other tissues could not be rendered as exquisitely susceptible to impressions from without if this were beneficial to the organism, as is the nervous system of the higher animals.’ Darwin had earlier speculated, in a letter to Hooker, that ‘if plants have diffused nervous matter’ one would expect ‘some degree of analogous action.’ He continued: ‘And this is partially the case. Considering these experiments [on the passing of a signal from the tentacle to the basal part of the plant], I cannot avoid the conclusion, that Drosera possesses matter at least in some degree analogous in constitution & function to nervous matter.’ Such conclusions were not lost on Darwin’s readers either: the acclaimed orchid expert John Lindley, on reading Darwin’s plant studies, exclaimed that his theories ‘shake to the foundation all our ideas of the stability of genera and species.’ Stable boundaries between human and nonhuman collapse as the reader is reminded that in a Darwinian world, differences are ultimately a matter of ‘degree and not of kind.’

“Perhaps not surprisingly, with this talk of analogous nervous systems, of key structures and tissues shared between flora and fauna, Darwin opened the door for an avalanche of anxiety among his extensive readership. Commentators, looking at the Darwinian plant world, were driven to ask: ‘Are plants able to think?’ ‘Can plants feel?’ ‘Is there … a consciousness in vegetable organisms?’ ‘Are those plants that are endowed with the power of motion as a result of sensation capable of connecting the sensation of touch with their movements by any process of thought? What is thought? … Is there any connection between these similar actions of these plants and animals, and if so, are they not due to the same cause’” (Gianquitto, pp. 241-4).

“The first 10 chapters of Insectivorous Plants present the sundew experiments designed to determine what types of substances triggered movement of the sticky trichomes to wrap around prey and stimulated secretion of the digestive fluid. He came to realize that only nitrogen-containing substances, such as high-protein foods like meat, egg white, milk, and peas, elicited the full carnivorous response.

“Darwin also examined the nature of the digestive fluid secreted by the leaves. His observations provide an example of the effect of pH on enzyme activity in a natural system. He tested the digestive fluid of the sundew with litmus paper and found it to be acidic. If he added alkali to the fluid, digestion stopped. If he then added acid, digestion resumed. Darwin observed that acid alone did not digest the substances. A ‘ferment,’ which we would now call a ‘protease’ (an enzyme that breaks down proteins to amino acids), was also required.

“Likening sundews to animals, Darwin tried various poisons that impair animals to see if they would block any part of the response in sundews. He was surprised to see that a solution of cobra venom actually stimulated it. This response that stumped Darwin provides an opportunity to apply new knowledge to solve an old problem. Now that we know that cobra venom is a protein, we can understand why applying it to a sundew leaf would trigger the carnivorous response.

“In Insectivorous Plants, Darwin made reference numerous times to the pollen grains, leaf fragments, and seeds found on the sticky leaves of sundews and butterworts (Pinguicula). He tested to see if these substances were digested and absorbed and found that they were. He concluded that these plants get at least some of their resources from plant matter …

“Darwin also studied the Venus flytrap (Dionaea muscipula). His report on this plant stands out because it illustrates his thought process as he determined what adaptive value a feature might have for an individual organism. The leaf of the flytrap is edged with spine-like projections, and he was curious as to their usefulness. As he watched a leaf close around its prey, he observed that these spiny projections form bars like those of a cage. He surmised that small insects would be able to escape before the leaf closed completely and the plant committed resources to the full digestion and absorption process. Larger, more worthwhile prey would be unable to get out. He made an analogy to a fishing net with a large mesh that would allow small fish to escape while keeping large fish ensnared. He wanted to know if he was correct about Venus flytraps catching insects under natural conditions. Because the Venus flytrap is not native to England, he asked a North American naturalist for help in observing insects caught by plants growing in the wild in North Carolina. The naturalist mailed Darwin some closed leaves containing prey so that Darwin could see and measure the insects for himself. He concluded that his proposal about the function of the spiny projections on the edges of the leaves was correct.

“In the conclusion of Insectivorous Plants, Darwin put carnivory in the larger context of the methods by which plants obtain resources. The ‘ordinary plants’ absorb minerals from the soil with their roots. Among the carnivores, he recognized two groups. Although both ensnare their prey and absorb the digested material, one group digests the prey directly, whereas the other relies on microbial flora to do the digestion. For completeness, he mentioned parasitic plants and mycotrophic plants, which rely on mycorrhizal fungi to pass them materials from a woody plant. This summary supports the recurring theme of all of Darwin’s investigations, that a variety of adaptations are found among diverse organisms to accomplish the same task” (Harley).

The book was published on July 2, 1875, in a standard binding without inserted advertisements. It is stated that 3,000 were printed of which 2,700 were sold to the trade at once. This cannot be strictly true because both the second and third thousands of the same year stated their thousands on the title pages. The second has an errata slip of six lines, and in the third these six have been corrected, but another six have been found and again occur on a slip. The same slip is present in the fourth thousand of 1876. It was not printed again in Darwin’s lifetime, but a second edition, edited by Francis appeared dated 1888. According to Murray's list this was issued in January 1889. It contains some small corrections taken from Darwin’s marked copy of the first edition, as well as textual additions and footnotes by his son which are all contained in brackets” (Freeman).

Freeman 1217; Norman 601. Gianquitto, ‘Criminal botany: progress, degeneration, and Darwin’s insectivorous plants,’ in: America’s Darwin: Darwinian evolution and U.S. culture (Gianquitto & Fisher (eds.), 2014. Harley, ‘Charles Darwin’s Botanical Investigations,’ The American Biology Teacher 72 (2010), pp. 77-81.

8vo (182 x 123 mm), pp. [v], vi-x, [1], 2-462, with 30 wood-engravings in text. Original green cloth, gilt titles and decoration to spine, blind-panelled covers, brown coated endpapers.

Item #5268

Price: $19,500.00