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Darwin Correspondence Project

Before Origin: the ‘big book’

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Natural selection chapter 5 manuscript page
Natural selection chapter 5 manuscript page

Darwin began ‘sorting notes for Species Theory’ on 9 September 1854, the very day he concluded his eight-year study of barnacles (Darwin's Journal). He had long considered the question of species. In 1842, he outlined a theory of transmutation in a short pencil sketch, and in 1844, he once again committed his thoughts to paper in a more substantial essay. By this point, Darwin had also admitted to his close friend and confidant Joseph Hooker that he believed he had found out ‘the simple way by which species become exquisitely adapted to various ends’ and was ‘almost convinced’ that species were not immutable—a view so controversial that it was, he acknowledged, ‘like confessing a murder’. While Darwin recognised he had far more work to do before presenting his views publicly, he was so convinced of their merit that he made plans for his essay to be edited and published in the event of his sudden death. Later in 1844, he told the naturalist Leonard Jenyns that he had been ‘steadily reading & collecting facts on variation of domestic animals & plants & on the question of what are species’, and possessed ‘a grand body of facts’ from which he could draw ‘some sound conclusions.’ Nonetheless, when the anonymous Vestiges of the Natural History of Creation caused a publishing sensation in October 1844, the public reaction to the transmutation theory it contained convinced Darwin that further evidence for the fact of evolution had to be gathered and presented before his species theory would be accepted. He declared himself to be both ‘flattered & unflattered’ when some readers attributed the authorship of Vestiges to him. It took another ten years before Darwin felt ready to start collating his evidence of evolution and thinking about what he came to call his ‘big book’.  

In March 1854, six months before he started sorting his species notes, Darwin had worried that the process would reveal the untenability of his views. ‘How awfully flat I shall feel, if I when I get my notes together on species &c &c, the whole thing explodes like an empty puff-ball’, he told Hooker. Darwin’s concern may have stemmed from Hooker’s own work. When Darwin had read the introduction to Hooker’s Flora of New Zealand in October 1853, he discovered that it contained several points that challenged his theory. ‘In a year or two’s time, when I shall be at my species book, (if I do not break down) I shall gnash my teeth & abuse you for having put so many hostile facts so confoundedly well’, he fretted at the time. However, by March 1855, he was immersed in the preparatory stages of his own book, fully taking on board the need to take account of the many obstacles to his theory. ‘‘I am hard at work on my notes, collating & comparing them, in order in some 2 or 3 years to write a book with all the facts & arguments, which I can collect, for & versus the immutability of species’, he told his cousin William Darwin Fox.

Experimental work

Darwin outlined the aims of his species book to Fox because he needed help with one of the practical experimental programmes he wish to set up to provide crucial evidence for his arguments. Fox, Darwin assumed, would have bred pigeons at some point, and could therefore provide information on their development so that Darwin would not be ‘cheated & gulled’ by the sellers from whom he intended to purchase birds. Fancy pigeons, that is, those varieties intensely bred to exaggerate particular characters, would, Darwin believed, clearly exhibit the stage at which differences between their young became apparent.  In order to determine this, Darwin realised that he might not be able to buy young enough pigeons and might have to breed them himself. Pigeon breeding, he anticipated, would provide ‘no amusement’ and be a ‘horrid bore’. Contrary to Darwin’s expectations, however, the pigeon house constructed at Down in April 1855 did not look ‘very ugly’, the breeding of fancy pigeons proved enjoyable and enlightening, and the birds were a delight to his young daughter Henrietta.

In April 1855, at the same time as Darwin began his pigeon breeding programme, he started a series of ‘seed-salting experiments’ to determine whether seeds could survive transport by the oceans.  Hoping to benefit from Hooker’s botanical expertise, Darwin inquired: ‘will you tell me at a guess how long an immersion in sea-water you shdimagine wd. kill the more susceptible seeds? Should you expect a week’s fair immersion wd. destroy any of them?’ A few days later, he expanded his request for information to the entire natural history community by sending a letter to the Gardeners’ Chronicle, asking whether such experiments had been tried before and explaining that his aim was to throw light on the distribution of plants. By May, he could report to the readership of the magazine that he had experimented on a random selection of seeds, but he was ‘now trying a set chosen on philosophical principles by the kindness of Dr. Hooker’. His investigation involved dealing with ill-smelling and putrid water as a result of soaking the seeds for long periods; having to varying the temperature at which the containers in which the seeds were being soaked; and then, in some cases, planting seeds so slimy that they cohered in a mass.  Nonetheless, the surprising result was that many of the seeds germinated after their salty ordeal, providing a means to explain geographical distribution of plants that did not rely on the hypothetical land bridges suggested by the naturalist Edward Forbes. Darwin declared to Hooker in July 1856 ‘you continental extensionists would remove enormous difficulties opposed to me, & yet I cannot honestly admit the doctrine’. Darwin thought Forbes’ hypothesis ‘an almost retrograde step in science’, and one which ‘cuts the knot instead of untying it.

Persuading men of science

Darwin’s patient untying of the knot of evolutionary theory, and his awareness of the information he still needed, was based on the observational and experimental evidence he had been gathering over a long period.  ‘Nineteen years (!) ago’, he wrote to the American botanist Asa Gray in July 1857,

it occurred to me that whilst otherwise employed on Nat. Hist, I might perhaps do good if I noted any sort of facts bearing on the question of the origin of species; & this I have since been doing. … I assume that species arise like our domestic varieties with much extinction; & then test this hypothesis by comparison with as many general & pretty well established propositions as I can find made out,—in geograph. distribution, geological history—affinities &c &c &c.. And it seems to me, that supposing that such hypothesis were to explain general propositions, we ought, in accordance with common way of following all sciences, to admit it, till some better hypothesis be found out. … as an honest man I must tell you that I have come to the heteredox conclusion that there are no such things as independently created species—that species are only strongly defined varieties. I know that this will make you despise me.— I do not much underrate the many huge difficulties on this view, but yet it seems to me to explain too much, otherwise inexplicable, to be false. … I was much pleased to find that it seemed to have considerable weight with Hooker, who said he had never been so much staggered about the permanence of species.—

By 1857, Darwin had found the confidence to describe his views on species to a select group of fellow naturalists. Gray’s response was everything Darwin must have hoped for. Stating that his experience as a botanist had led to him to have ‘many misgivings about the definiteness if species’, Gray expressed his interest in Darwin’s work because it began with ‘good, tangible facts’. Not all those that Darwin chose to tell were so favourable. His old friend Hugh Falconer, he confessed to Gray, ‘attacked me most vigorously, but quite kindly, & told me “you will do more harm than any ten naturalists will do good”— “I can see that you have already corrupted & half-spoiled Hooker”(!!). Now when I see such strong feeling in my oldest friends, you need not wonder that I always expect my views to be received with contempt.’ However, it was not responses like this that led Darwin to ask that his species theory still be kept secret, but his fear of those who would receive his views with open arms. Since its publication in 1844, the transmutationist work Vestiges of the Natural History of Creation had gone through ten editions and was still selling well. Darwin was worried about plagiarism and being tainted by association with works like this. ‘You will, perhaps, think it paltry in me, when I ask you not to mention my doctrine’, he told Gray, ‘the reason is, if anyone, like the Author of the Vestiges, were to hear of them, he might easily work them in, & then I shd. have to quote from a work perhaps despised by naturalists & this would greatly injure any chance of my views being received by those alone whose opinion I value.—

Darwin’s increasing confidence was built on the support of those closest to him: none more so than that of his old friend, the geologist Charles Lyell, who, in May 1856, twenty months after Darwin had begun sorting his species notes, urged him to guard against pre-emption by writing and publishing a ‘sketch’ of his theory (Darwin's Journal). Just a month earlier, Lyell’s brother-in-law Charles Bunbury had expressed his interest and delight in Darwin’s ‘researches & speculations on species & variation & distribution’. ‘I trust that you will not on any account give up the idea of publishing your views upon it’, he urged Darwin,’tho’ neither you nor any one else may be able to unravel the whole mystery, or to command the universal assent of naturalists, still the researches of one who has studied the whole question so long, & with such extensive knowledge & in so philosophical a spirit, cannot fail to be of very great advantage to science.’ Bunbury also advised giving the facts and arguments on each side. ‘I say this,’ he told Darwin, ‘because the theory to which you lean is the most remote from that to which I incline, & yet I am quite ready to admit that your notion may be the right one.

Short sketch or big book?

Darwin was thoroughly aware that the public acceptance of his views would depend on empirical evidence and solid argument. He decided to introduce the question of species by focussing on domesticated animals, basing his arguments on knowledge that would be familiar to many of his readers. Not least, Darwin’s own views on how species change was based on ‘long-continued study of the works of (& converse with) agriculturists & horticulturists’ from which he could clearly see ‘the means used by nature to change her species & adapt them to the wondrous & exquisitely beautiful contingencies to which every living being is exposed.’ Darwin also understood the urgency to publish and, following Lyell’s advice in May 1856, began to write a sketch his theory. ‘I rather hate the idea of writing for priority, yet I certainly shd. be vexed if any one were to publish my doctrines before me’, he admitted, while also insisting that it was ‘absolutely impossible’ to give a ‘fair’ sketch because ‘every proposition requires such an array of facts’: at best he could ‘refer to the main agency of change, selection’.

From the start, Darwin was also adamant that his sketch should appear as ‘very thin & little volume’, and not in a periodical for fear that the editors might be ‘abused’ for allowing such a publication. Moreover, he could not shake off his ‘idea that it was ‘dreadfully unphilosophical to publish without full details.’ Writing to his cousin Fox in June 1856, Darwin openly confessed his fears that a sketch would be ‘horridly imperfect & with many mistakes’. Whatever Fox stated in reply, Darwin stated that it gave him ‘another fit of the wibber-gibbers’. By October, Darwin declared that Fox’s remarks against publishing a sketch had ‘weighed’ with him considerably, and because he found the writing ‘such unsatisfactory work’ he had ‘desisted’. By November 1856, he had both good and bad news to report to Lyell: ‘I am working very steadily at my big book; I have found it quite impossible to publish any preliminary essay or sketch; but am doing my work as completely as my present materials allow without waiting to perfect them. And this much acceleration I owe to you.’ In February 1857, the rate of this acceleration was revealed, when he told his cousin Fox: ‘I am working very hard at my Book, perhaps too hard. It will be very big…  I am like Crœsus overwhelmed with my riches in facts. & I mean to make my Book as perfect as ever I can. I shall not go to press at soonest for a couple of years.’ Darwin’s prediction was correct. He did not publish until 1859, but he had no idea that it would not be his ‘big book’ rolling off the printing press.

Although Darwin had decided in the autumn of 1856 to write only from the materials he had already accumulated, questions of geographical distribution and dispersal could not be resolved without further empirical evidence. He wanted to extend his seed-salting experiments in order to determine the mean of dispersal of land molluscs; the question was driving him mad, but he was unable to get land mollusc eggs ‘to experimentise on their power of floating & resistance to injurious action of salt-water.’ It was only when T. V. Wollaston sent Darwin several hundred snails from Madeira that he was able to carry out the experiment. To his surprise, he discovered that effect of sea-water on land molluscs’ eggs was not ‘quite so deadly’ as he anticipated. Darwin had also been flummoxed by the distribution of fresh-water molluscs; it had been a ‘horrid incubus’ to him, until, with the help of Philip Henry Gosse, he discovered that the very active young crawled on and adhered to birds’ feet, where they could survive out of water for between 15 and 24 hours. Darwin also enlisted the help of others when he began to investigate whether seeds were transported in the earth that stuck to birds’ feet. In addition, he requested permission to ‘experimentise’ on the hawks in the Zoological Gardens. He was delighted when the birds ‘behaved like gentlemen’ and ‘cast up pellets with lots of seeds in them’. The success of these dispersal experiments was measured by whether the seeds and eggs survived and developed, but Darwin was also experimenting on the germination and survival of plants in what he called his ‘weed garden’—a cleared plot of land 3 x 2 feet on which he let seedlings spring up. This provided Darwin with a microcosm of the struggle for existence, and a tiny arena for exhibiting competition in nature. Darwin’s combination of this very specific experimental activity with writing was evidently successful. ‘I am become most deeply interested in the way facts fall into groups’, he told Fox in February 1857.

Trials of strength

Darwin wrote ten and a half chapters of his Big Book between May 1856 and June 1858. With a total of around a quarter of a million words, the work was about half complete. ‘It is a most tiresome drawback to my satisfaction in writing, that though I leave out a good deal & try to condense, every chapter runs to such an inordinate length’, he had complained to Hooker in December 1856. By mid-1858, only the first chapter on breeding and variation under domestication remained in a rough state; the other chapters had been revised and some even sent to scientific specialists for comments. Thomas Henry Huxley, for example, was asked to check just two pages on the connection between embryonic development and genealogical relationship in the chapter on the Laws of Variation ‘& consider the little point therein referred to.’ Darwin, who had drawn on the research of others to make his argument, realised that he was on ‘unsafe ground’, but Huxley’s reply proved it to be ‘far unsafer’ than he had thought, leading him to omit the discussion from his chapter. Hooker not only supplied a ‘magnificent & awful’ box of botanical works when Darwin wished to tabulate of the number of species in small and large genera, but also read Darwin’s draft discussion of the results in April 1858. Darwin was anxious to know whether this ‘odious’ work that had ‘almost killed’ him was worth publishing in full. Aware that Hooker as a botanist might find some remarks in this section trivial, Darwin reminded him that the work was ‘written for geologists & zoologists’, and that throughout his aim was ‘to show what points ought to be considered in theory of the descent of species’. In December 1857, Darwin had expressed his satisfaction that the naturalist Alfred Russel Wallace, who was collecting in the Malay Archipelago, was investigating animal distribution ‘in accordance with theoretical ideas’. ‘I am a firm believer’, he told Wallace, ‘that without speculation there is no good & original observation’.

In 1857, Darwin recorded in his journal that he ‘lost’ a month of that year at Moor Park, a hydropathic establishment in Surrey. While there, he wrote to Wallace. Praising Wallace’s 1855 article on species, and commenting on the convergence of their conclusions, Darwin expressed the hope that before his own work on species was finished he might benefit from Wallace’s ‘large harvest of facts’ from the Malay Archipelago. ‘This summer will make the 20th year (!) since I opened my first-note-book, on the question how & in what way do species & varieties differ from each other’, he told Wallace in May 1857, before stating ‘I am now preparing my work for publication, but I find the subject so very large, that though I have written many chapters, I do not suppose I shall go to press for two years. Wallace was intrigued as to whether Darwin would discuss humans in his book. ‘I think I shall avoid whole subject, as so surrounded with prejudices’, Darwin replied in December, ‘though I fully admit that it is the highest & most interesting problem for the naturalist.’ He was clear about his purpose of his big book. ‘My work … will not fix or settle anything; but I hope it will aid by giving a large collection of facts with one definite end’. Darwin continued to write steadily until April 1858, when he again needed to visit Moor Park because his stomach, through overwork, had got into a ‘horrid state’. ‘My work is everlasting’, an exhausted Darwin stated four days before he set off for the water cure.

After two weeks at Moor Park, where the water-cure did ‘wonderful good’, Darwin recommenced writing in May 1858. ‘This work will be my biggest’, he told Syms Covington, his assistant during the Beagle voyage, ‘it treats on the origin of varieties of our domestic animals and plants, and on the origin of species in a state of nature. I have to discuss every branch of natural history, and the work is beyond my strength and tries me sorely.’ Darwin, however, was to be tried far more sorely in the following month. Wallace, who had continued to pursue his work on species theory while in the Malay Archipelago, decided to send his views to the two men of science he felt could judge it adequately. On 18 June 1858, Darwin received a now lost letter from Wallace enclosing his essay titled on 'On the Tendency of Varieties to depart indefinitely from the Original Type', which Wallace asked to be forwarded to Lyell (Wyhe 2012). Writing to Lyell immediately, Darwin was contrite. ‘Your words have come true with a vengeance that I shd. be forestalled’, he told Lyell, ‘I never saw a more striking coincidence. if Wallace had my M.S. sketch written out in 1842 he could not have made a better short abstract! … So all my originality, whatever it may amount to, will be smashed.’ Before the day was out, Darwin’s miseries increased. His daughter Henrietta fell seriously ill with the ‘most suffering illness’. This turned out to be a ‘horrid new complaint’ called diphtheria. Then, on 23 June, Darwin’s infant son, Charles, ‘commenced with Fever of some kind’. Despite his anxiety about his children, on 25 June Darwin was liaising with Lyell about how best to proceed to protect his intellectual work and species theory of twenty years’ standing: ‘as I had not intended to publish any sketch, can I do so honourably because Wallace has sent me an outline of his doctrine?— I would far rather burn my whole book than that he or any man shd. think that I had behaved in a paltry spirit.’ Three days later, the baby died of scarlet fever and his nurse had sickened. The following day, Darwin accepted Lyell and Hooker’s suggestion that they submit Wallace’s essay together with extracts from Darwin’s writing as a joint paper to the Linnean Society of London. The aim was to establish Darwin’s priority. Exhausted and distraught with grief, Darwin himself was pessimistic: ‘I daresay all is too late. … It is miserable in me to care at all about priority.

By 5 July, the Darwin family was less ‘panic-struck’ about the illness in the house, and Hooker had reported that presentation of the joint paper at the Linnean Society had ‘gone on prosperously’. Darwin declared himself ‘much more than satisfied at what took place at Linn. Socy’. Wallace, however, did not hear about any of these events for months. When he received (now lost) letters from Darwin and Hooker, he appeared, for different reasons, to have been equally pleased. Writing to his mother in October 1858, Wallace stated ‘I sent Mr. Darwin an essay on a subject upon which he is now writing a great work. He showed it to Dr. Hooker and Sir Charles Lyell, who thought so highly of it that they had it read before the Linnean Society. This insures me the acquaintance of these eminent men on my return home.’ (Wallace 1905, 1: 365) On the day that Darwin sent his and Hooker’s letters to Wallace, he had told Hooker ‘I always thought it very possible that I might be forestalled, but I fancied that I had grand enough soul not to care; but I found myself mistaken & punished; I had, however, quite resigned myself & had written half a letter to Wallace to give up all priority to him & shd. certainly not have changed had it not been for Lyell’s & yours quite extraordinary kindness. I assure you I feel it, & shall not forget it.’ By the time that Wallace heard about the presentation of his work at the Linnean Society, Darwin was well into the preparation of the abstract of his big book that would be published as the Origin of Species in November 1859.


Despite the impact and success of Origin, Darwin did not give up on the idea of completing his big book. The blanks sides of the pages were not used by the Darwin children for drawing and painting as was the case with the draft of Origin. Even when Darwin realised that he might lose priority in his species theory and that all his originality would ‘be smashed’, he knew that his big book, ‘if it will ever have any value, will not be deteriorated; as all the labour consists in the application of the theory.’ Darwin always intended to complete this work, but as he worked on it daily in May 1863, he admitted that there ‘never will be a man who will read my big book; it will be a sort of encyclopedia on special cases.’ In 1860, he had declared that he intended to leave Origin as it was (except for corrections) and prepare three large volumes of his ‘bigger work’. However, by the time Darwin had published Variation under domestication in 1868, which was based on the first two chapters of the big book, he was too ‘fatigued’ to start work on his second proposed volume ‘on the variation of species in a state of nature.’ Instead, Darwin simply raided his text for information for later works such as Descent, Different forms of flowers, and Cross and self-fertilisation, just as he had done when writing Origin. He also allowed substantial sections of his chapter on mental powers and instinct to be published by George John Romanes in two of his books which came out shortly after Darwin's death. ‘You are quite welcome to have my longer chapter on Instinct’, Darwin told Romanes in June 1878, ‘I have never had time to work it up in a state fit for publication; & it is so much more interesting to observe than to write.’ The first two chapters of the big book that formed the basis of Variation are no longer extant; the remaining eight and a half chapters were edited and published in 1975 by R. C. Stauffer under the title Charles Darwin’s Natural Selection; being the second part of his big species book written from 1856 to 1858 (Cambridge University Press). 



Wyhe, John van. 2012. A new theory to explain the receipt of Wallace's Ternate Essay by Darwin in 1858, Biological Journal of the Linnean Society 105: 249-52

Wallace, Alfred Russel. 1905. My life: a record of events and opinions. 2 vols. London: Chapman & Hall