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Darwin Correspondence Project

Life sciences

Over the course of his working life Darwin studied a wide range of organisms from coral to worms, dogs to pigeons, orchids to carnivorous plants.  His letters often describe in great detail experiments and observations some of which never made it into print.


Drosera rotundiflora
Drosera rotundiflora, figures 4 & 5 from Insectivorous Plants
Image from the Biodiversity Heritage Library. Digitised by Princeton Theological Seminary Library (

Insectivorous plants

Darwin’s work on insectivorous plants began by accident. While on holiday in the summer of 1860, staying with his wife’s relatives in Hartfield, Sussex, he went for long walks on the heathland and became curious about the large number of insects caught by the common sundew (Drosera rotundifolia). He reported to his friend Joseph Dalton Hooker: ‘I amused myself with a few observations on the insect-catching power of Drosera; & I must consult you some time whether my “twaddle” is worth communicating to Linnean Soc.’ Although he continued to think of his studies of carnivorous plants as a guilty pleasure, this encounter began a long-running research project that showed some of the connections between plants and animals.

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Nomenclature of the valves.jpg

Nomenclature of the valves
Darwin's nomenclature of the valves, Lepadidae, fig. 1

Living and fossil cirripedia

Darwin published four volumes on barnacles, the crustacean sub-class Cirripedia, between 1851 and 1854, two on living species and two on fossil species. Written for a specialist audience, they are among the most challenging and least read of Darwin’s works and are often dismissed as a necessary detour on the road to the development of the theory of evolution through natural selection. These volumes reveal, in fact, how observation, experiment, and classification both informed and were informed by Darwin’s species theory. Every aspect, from the choice of subject to the production of the volumes, reveals something about Darwin’s approach to scientific investigation. While appearing to conform to long-established practice, Darwin introduced a new approach to systematics that challenged the purely morphological methodology of his predecessors.

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Hall of Biodiversity.jpg

Hall of Biodiversity, American Museum of Natural History
Hall of Biodiversity, American Museum of Natural History
Ryan Somma, Flickr

Biodiversity and its histories

The Darwin Correspondence Project was co-sponsor of Biodiversity and its Histories, which brought together scholars and researchers in ecology, politics, geography, anthropology, cultural history, and history and philosophy of science, to explore how aesthetic, economic, and moral value came to be attached to the diversity of life on earth.  The conference included a session on 'Darwin and evolutionary theory' involving past and present members of the Project. 

We are grateful to the speakers for permission to make their talks available here.

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“Mr. Arthrobalanus” a barnacle observed by Darwin on board the Beagle
“Mr. Arthrobalanus” a barnacle observed by Darwin on board the Beagle
CUL DAR 29.3: 72
Cambridge University Library

Darwin and barnacles

In a letter to Henslow in March 1835 Darwin remarked that he had done ‘very little’ in zoology; the ‘only two novelties’ he added, almost as an afterthought, were a new mollusc and a ‘genus in the family Balanidæ’ – a barnacle – but it was an oddity. Who, he wondered ‘would recognise a young Balanus in this ill-formed little monster?’ Darwin put his specimens away for over a decade, and when he returned to the puzzling little creature in October 1846, he planned only to write a paper on the anomalous ‘Mr Arthrobalanus’, as it was now known to him.  The work took him eight years. 

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Frances Power Cobbe
Frances Power Cobbe, Fom: Life of Frances Power Cobbe by Herself, Published: 1894
Wellcome Library, London

Darwin and vivisection

Darwin played an important role in the controversy over vivisection that broke out in late 1874. Public debate was sparked when the Royal Society for the Prevention of Cruelty to Animals brought an unsuccessful prosecution against a French physiologist who had performed vivisection on dogs.

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Man is but a worm - caricature of Darwin's theory in the Punch almanac for 1882
Man is but a worm - caricature of Darwin's theory in the Punch almanac for 1882
CUL T992.b.1.45
Cambridge University Library

Casting about: Darwin on worms

Earthworms were the subject of a citizen science project to map the distribution of earthworms across Britain (BBC Today programme, 26 May 2014). The general understanding of the role earthworms play in improving soils and providing nutrients for plants to flourish can be traced back to the last book Darwin wrote, snappily-titled 'The formation of vegetable mould through the action of worms with observation on their habits', which was published in 1881. Despite Darwin’s fears that a book on earthworms might prove a failure, it became a best seller.

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Darwins Cirripedia microscope slides
Darwins Cirripedia microscope slides
By kind permission of Cambridge University Museum of Zoology

Getting to know Darwin's science

One of the most exciting aspects of Charles Darwin’s correspondence is the opportunity it gives to researchers to ‘get to know’ Darwin as an individual. The letters not only reveal the scientific processes behind Darwin’s publications, they give insight into his personal life–the world of his family, his circle of friends and his community. This set of resource modules has been designed with the hopes of sharing some of the knowledge gained from our work on Darwin’s correspondence with university students.  

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Down House hothouse
Down House hothouse, engraving from Century Illustrated Monthly Magazine, Jan. 1883
Cambridge University Library

Darwin’s hothouse and lists of hothouse plants

Darwin became increasingly involved in botanical experiments in the years after the publication of Origin. The building of a small hothouse - a heated greenhouse - early in 1863  greatly increased the range of plants that he could keep for scientific investigations, in particular tropical plants for his experiments into their sensitivity to touch. He was persuaded to build it - an expensive undertaking - by a neighbour's gardener who had been helping Darwin use his employer’s hothouses over the previous two years.  Darwin enjoyed looking through plant catalogues and making lists of exotic specimens with which to stock the hothouse, and it proved so valuable, and the work so engrossing, that in the end he built a complex of greenhouses capable of sustaining a wide range of species.

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Darwin and Down

Charles and Emma Darwin, with their first two children, settled at Down House in the village of Down (later ‘Downe’) in Kent, as a young family in 1842.   The house came with eighteen acres of land, and a fifteen acre meadow.  The village combined the benefits of rural surroundings, where Darwin could make observations and undertake experiments in natural history, with reasonable ease of access to London, and was the environment within which Darwin’s work over the last forty years of his life was almost exclusively conducted.

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George Douglas Campbell, 8th Duke of Argyll
George Douglas Campbell, 8th Duke of Argyll, by George Frederic Watts, oil on panel, circa 1860, NPG 1263
© National Portrait Gallery, London

Beauty and the seed

One of the real pleasures afforded in reading Charles Darwin’s correspondence is the discovery of areas of research on which he never published, but which interested him deeply. We can gain many insights about Darwin’s research methods by following these ‘letter trails’ and observing how correspondence served as a vital research tool for him.

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