Johann Mendel (1822-1884) was born in Heinzendorf, Austrian Silesia (Hynčice, Czech Republic). After studying at the University of Olmütz (Olomouc, Czech Republic) Johann joined the Augustinian order at the Altbrünn monastery in 1843 where he took the name Gregor. He taught for several years in Znaim (Znojmo, Czech Republic) before failing a compulsory exam for teacher certification in 1850. In 1851 his Abbot sent him to the University of Vienna for two years where he studied physics and mathematics briefly under the ailing Christian Doppler, and then under Christian von Ettinghausen, and plant anatomy and physiology under Franz Unger. In 1853 Mendel returned to Brünn (Brno) and in 1854 began teaching physics and natural history at the Brünn Realschule (secondary school). A position he held until his election as Abbott in 1867.
In 1854 Mendel’s Abbot, Cyril Napp, approved Mendel’s proposal to carry out a major experimental program in hybridization, with the aim of tracing the transmission of hereditary characters in successive generations of hybrid progeny. Mendel opted to conduct his studies using the humble pea, Pisum sativum and from 1854 to 1856 he tested 34 varieties for constancy in their traits. He presented his findings during two sessions on 8th February and 8th March 1865 to the Natural Science Society in Brünn, an institution Mendel had co-founded in 1861, in a paper titled Versuche über Pflanzenhybriden (Experiments in Plant Hybridization). The paper was published in the relatively obscure journal of the society and Mendel arranged for forty copies to be printed and distributed.
During his lifetime Mendel received little recognition. Several of the surviving original prints of his paper have uncut pages, and just fifteen citations of his paper are known from the Nineteenth Century. After his elevation to Abbot in 1868 Mendel devoted less time to his scientific work as a result of the responsibilities of his position. He died on January 6, 1884, from chronic nephritis, aged 61. The independent discovery of his findings by Hugo de Vries, Carl Correns, Erich von Tschermak, and William Jasper Spillman saw Mendel credited with the scientific discoveries that form the basis of genetics and secured his reputation as the father of the discipline.
His reputation has not gone unchallenged however. In 1911 whilst studying at the University of Cambridge Ronald Fisher accused Mendel of bias in his experiments, an accusation he was to repeat in 1936, concluding that there was one chance in 30,000 that Mendel could have arrived at his results by chance: an allegation repeated by Fisher’s pupil, A. W. F. Edwards, in the 1980’s. More recently John Waller has echoed Fisher’s claim that, “each generation found in Mendel’s paper only what it expected to find,” by arguing that the popular conception of Mendel as the father of genetics is not accurate because biologists in the Twentieth Century have consistently read fundamental ideas into his 1865 paper that were not there.
Waller’s chapter on Mendel appears in a wider work in which he, like Pollio in the passage from Robert Graves’, I Claudius, that Waller references in his introduction, seeks to uphold the view that the, “historian’s ultimate duty is to the Truth.” It is a laudable sentiment and particularly apt when considering the legacy of Mendel. As Jan Sapp points out, “there is no greater legend in the history of science than that of the experiments of Gregor Mendel.” For the majority of the scientific community Mendel’s reputation remains intact. His work fits well with a modern narrative of exemplary science and ground breaking genius. By using peas he chose the right organism for the job; his work was qualitative, thorough, and demonstrated hard work and tenacity; the rediscovery of his work after his peers failed to appreciate it demonstrates scientific truth prevailing over social prejudice; he was right, science does not err; he was a humble seeker after truth rather than fame or wealth. Whether Corcos and Mongahan’s somewhat sweeping statement that “most geneticists have little time or inclination to delve into the history of their discipline because they are concerned with the latest research … very few people have read Mendel’s paper and, among those who have, very few have understood it,” is correct or not is open to debate. Yet there would seem to be grounds for arguing that the popular understanding of Mendel’s work and his historical legacy are misleading.
The fundamental problem faced by anyone researching Mendel is the lack of sources. He did not keep a diary and wrote little about himself. His published work consists of two papers, Versuche über Pflanzenhybriden (1866), and Ueber einige aus künstlicher Befruchtung gewonnenen Hieracium-Bastarde (1869), with his only other work in print being his letters to Carl Nägeli written between 1866 to 1873. Many of Mendel’s papers were sadly destroyed by his successor as Abbot, leaving a yawning chasm in the source material on which later scientists and historians have to rely. This has not prevented widespread and contradictory interpretation of his work however. In his Nine Lives of Gregor Mendel, Sapp summarises these interpretations:
1. Mendel was a non-Darwinian. Although Mendel was an evolutionist, he did not entirely agree with Darwin’s views and set out to disprove them.
2. Mendel was a good Darwinian. His experimental protocols and reported results can be explained on the assumption that he had no objections to Darwinian selection theory.
3. Mendel was not directly concerned with evolution at all. He placed it on the back burner while he investigated the laws of inheritance.
4. Mendel rejected evolutionary theory.
5. Mendel laid out the laws of inheritance which justifiably carry his name.
6. Mendel was no Mendelian. He was not trying to discover the laws of inheritance, and several Mendelian principles are lacking in his papers.
7. Some of Mendel’s data was falsified.
8. None of Mendel’s data was falsified.
9. Mendel’s reported experiments set out in his paper of 1866 are wholly fictitious. 
Douglas Allchin uses the example of how the non-technical use of the word ‘dominance’ in the writing and teaching of genetics shapes students and popular thinking, arguing that the concept of dominance based on power and influence over others or another thing, rather than the genetic concept of dominance whereby one allelic form of a gene is expressed to the exclusion of another, has led to a misleading concept of genetics being taught to students and misunderstanding among the non-specialist reader.
Waller’s deconstruction of Mendel’s work and legacy, which draws heavily on the work of Robert Olby, is more extensive. In Waller’s opinion, “Mendel devoted most of his scientific life to what eventually proved to be an intellectual dead end.” Olby and Waller’s thesis rests on the argument that Mendel, rather than seeking to discover the principles of heredity, was seeking to demonstrate the evolutionary theory of Carl Linnaeus by proving that new species could evolve from hybrids: a theory that potentially married belief in God and the Creation with an evolutionary principle, understandably appealing to a Catholic monk.
Waller is happy to grant Mendel credit for the concepts of dominance and recessiveness, though quick to point out that this hardly made Mendel original, describing his grasp of the subject as, “good but unexceptional”. He then proceeds to argue that Mendel cannot be seen to have understood, or even envisaged, the Mendelian Laws which are named after him, the Law of Segregation and the Law of Independent Assortment, arguing that he lacked the modern understanding of allelic pairs and their role in the transmission of observable genetic traits, and that Mendel’s disregard of pure types in his findings demonstrates that Mendel saw segregation in hybrids as a special case. Further, Waller argues, after 1866 Mendel, “lost faith in the universality of his ratio,” suggested by his experiments on Pisum sativum. Mendel, Waller suggests, should not be considered a genius but one of the “under-appreciated,” host of, “scientific foot-soldiers, junior officers, and men and women of middle rank that account for the great majority of scientific advances.”
Strangely, given that he analyses Versuche über Pflanzenhybriden and quotes from it to reduce Mendel to the status of a worthy plodder bent on proving what we know today to be a fallacy, Waller does not include Versuche über Pflanzenhybriden, or indeed any work by Mendel in his ‘Notes on Sources’. Admittedly Waller’s book is a work of popular history, rather than an academic work, his footnotes are non-existent and his bibliography is not extensive, but it is a curious omission. Waller and Olby’s work raise a number of issues that lie at the heart of writing history, namely, the use which is made of source material through selective quotation, the citation of sources, and, more broadly in the consideration of Mendel’s work, the problems inherent in the use of translated material.
Two examples from Waller serve to demonstrate how selective quotation can misrepresent the evidence. The first relates to Mendel’s aim in conducting his experiment recorded in Versuche über Pflanzenhybriden. Waller states that, “Mendel claimed to be presenting the results of ‘a detailed experiment’, the aim of which was to establish a ‘generally applicable law governing the formation and development of hybrids’.” This closely follows Olby, who wrote, “the goal of his experiments is to discover a ‘generally applicable law governing the formation and development of hybrids’.” On the face of it this seems very clear. Both have directly and accurately quoted Mendel’s words – “’generally applicable law governing the formation and development of hybrids” – to explain to the reader what Mendel was trying to achieve.
The quote from Mendel is drawn from the second paragraph of Versuche über Pflanzenhybriden, which in full reads:
“That, so far, no generally applicable law governing the formation and development of hybrids has been successfully formulated can hardly be wondered at by anyone who is acquainted with the extent of the task, and can appreciate the difficulties with which experiments of this class have to contend.”
In context, the quote which Waller and Olby use to underpin the authority of their explanation of what Mendel was trying to achieve is actually part of a statement on the difficulty of arriving at a generally applicable law, rather than a statement by Mendel of his own aims. Quite why Waller and Olby chose to do this is open to conjecture, particularly when we consider that Mendel explicitly stated his aims in Versuche über Pflanzenhybriden when he wrote that:
“The object of the experiment was to observe these variations in the case of each pair of differentiating characters, and to deduce the law according to which they appear in successive generations.”
It must be recognised that this sits well with Waller and Olby’s explanation of what Mendel had set out to achieve. He was conducting the experiment in an attempt to identify a general law that described the transmission of phenotypic traits between successive generations. Why then did Waller and Olby take Mendel out of context when they wrote that his aim was to seek a ‘generally applicable law governing the formation and development of hybrids’?
The key word here is ‘hybrids’. Olby and Waller were both keen to emphasise that Mendel was not breaking new ground in the field we know today as genetics, but was instead seeking to prove the Linnean model of continuous evolution. By using Mendel’s phrase of a ‘generally applicable law governing the formation and development of hybrids’ Waller and Olby are able to add additional emphasis to their statements that Mendel’s paper is concerned with hybrids and hybridization rather than, as Waller put it, “‘The laws of hereditary transmission’ or ‘The mechanics of heredity’, nor even ‘Heredity in Pisum sativum’.” A very close echo of Olby who wrote, “How odd, then, it is that the terms ‘heredity’, ‘hereditary transmission’, and ‘laws of heredity’ do not appear in the title of the paper, but instead we have ‘Experiments on Plant Hybrids’.”
For a second example of selective quotation Waller writes that in 1865, at the close of his presentation of Versuche über Pflanzenhybriden, Mendel, “arguing that his experiments were inconclusive … lamely concluded that the results were not so clear that they had to be ‘unconditionally accepted’.” Again it is worth more fully quoting the passage in Versuche über Pflanzenhybriden from which the quote, “unconditionally accepted,” is taken:
“Gärtner, by the results of these transformation experiments, was led to oppose the opinion of those naturalists who dispute the stability of plant species and believe in a continuous evolution of vegetation. He perceives in the complete transformation of one species into another an indubitable proof that species are fixed with limits beyond which they cannot change. Although this opinion cannot be unconditionally accepted we find on the other hand in Gärtner’s experiments a noteworthy confirmation of that supposition regarding variability of cultivated plants which has already been expressed.” 
This appears to be a very particular usage in which the words, “unconditionally accepted,” have been taken out of context. Rather than describing his own work as inconclusive, as Waller infers, Mendel’s comment that an expressed opinion could not be, “unconditionally accepted,” clearly refers in this instance to Gärtner’s theories on the stability of species, and the bearing that Gartner’s work had in relation to the results from Mendel’s experiment.
Earlier in his chapter on Mendel, Waller tells the reader of a, “serious difficulty,” with Mendel’s Versuche über Pflanzenhybriden. Citing Robert Olby, Waller states that Mendel’s interpretation of Max Wichura’s work, that “willow hybrids ‘propagate themselves like pure species’,” was incorrect. According to Waller, Olby’s study of Max Wichura’s work demonstrated that Wichura had shown that willows have a strong predilection for reverting to ancestral forms.
Two points are worthy of note here. First, if Olby and Waller are correct, Charles Darwin made a similar mistake to Mendel in his interpretation of Wichura when he wrote that, “Max Wichura doubts whether hybrids ever revert to their parent forms.” The second relates to the proper citation of sources when writing history. Mendel’s phrase in reference to willow hybrids as quoted by Waller – “propagate themselves like pure species” – appears in Mendel’s 1869 paper, Ueber einige aus künstlicher Befruchtung gewonnenen Hieracium-Bastarde (On Hieracium-Hybrids Obtained by Artificial Fertilisation), where he wrote:
“Already in describing the Pisum experiments it was remarked that there are also hybrids whose posterity do not vary, and that, for example, according to Wichura the hybrids of Salix reproduce themselves like pure species.” 
This followed his earlier reference to Wichura in Versuche über Pflanzenhybriden:
“We meet with an essential difference in those hybrids which remain constant in their progeny and propagate themselves as truly as the pure species. According to Gärtner, to this class belong the remarkably fertile hybrids Aquilegia atropurpurea canadensis, Lavatera pseudolbia thuringiaca, Geum urbanorivale, and some Dianthus hybrids; and, according to Wichura, the hybrids of the Willow family.”
Mendel’s interpretation of Wichura, whether correct or not, is clearly consistent between both papers. What is problematic is that Waller never mentions Ueber einige aus künstlicher Befruchtung gewonnenen Hieracium-Bastarde. He only directly references Versuche über Pflanzenhybriden. The inference for the reader is that it is Mendel’s first paper that is the source of the quote, when clearly it is not. This may seem a minor point, yet it highlights an important concern in the writing of history, that of authority and veracity. Waller may be writing for a general rather than a specialist audience but that is not an excuse for ambiguity or for potentially misleading the reader.
Interestingly, Olby also fails to cite his sources for his interpretation of Wichura’s work in his 1997 paper, “Mendel, Mendelism and Genetics”. Despite mentioning Wichura nine times by name Olby provides neither footnotes, or a bibliographic entry for Wichura. This is a regrettable omission given that his bibliography includes forty-two items and he includes forty-six citations of the work of others, in all. Most significant is Olby’s failure to include a citation for his statement that:
“As for Wichura, Mendel’s misrepresentation of his claims is striking. The Breslau botanist recognized that many willow hybrids are perpetuated by asexual means, thus giving rise to whole clusters of hybrid plants, but he twice demonstrated reversion of willow hybrids experimentally.”
This is not say that Olby is not correct in relation to Wichura, but as he appears to be originator of the claim that Mendel got it wrong this is unfortunate, to say the least, for those who may wish to follow up his findings.
Olby’s claim that Wichura twice demonstrated reversion sits poorly with Waller’s statement that Olby’s study of Wichura shows willows strong predilection for reverting to ancestral forms. Olby accepts that Wichura found evidence of widespread hybridization in willows, but neither indicates whether these hybrids bred true, nor provides any quantitative evidence for the number of instances where hybrids did not revert to their pure species form, leaving the reader unable to determine whether the two recorded reversions are statistically significant or not.
Wichura’s work on willow hybrids, Die Bastardbefruchtung im Pflanzenreich, is, to the best of knowledge, only available in the original German as published by Morgenstern in 1865. Mendel’s work was also originally published in German. Not only does this make it difficult for non-German speakers to verify Olby’s interpretation of Wichura, it also reminds us of the importance for accurate translation from the original to the language of the reader.
Mendel’s original phrasing in Ueber einige aus künstlicher was, “unverandert wie reine arten fortpflanzen.” Waller renders this as, “propagate themselves like pure species,” while in 1997 Olby chose to write this as, “propagated themselves like pure species.” Many years earlier in 1901 Bateson translated the phrase as, “reproduce themselves as pure species.” Thus we see the original, “fortpflanzen,” a reflexive verb, rendered by three separate authors as, “propagate,” “propagated,” and “reproduce,” all transitive verbs. The differences may appear inconsequential. One of the beauties of English after all, is its ability to convey the same meaning via many different words. It is perhaps worth noting however, that Roget’s Thesaurus does not offer ‘reproduce’ as a synonym for ‘propagate’, and vice versa, while Collins online German-English Dictionary offers ‘reproduce’ rather than ‘propagate’ as the translation for fortpflanzen.
Of course none of the above criticisms of Waller and Olby negate their basic argument that Mendel’s work has been misinterpreted by later writers. They are right to remind us that analysis of Mendel’s work should consider the contemporary scientific and social framework in which he wrote and conducted his experiments, and Waller’s argument that Mendel and Darwin’s opposing views on evolutionary theory would not have led Darwin to recognise Mendel’s findings as the key to inheritance had he read Mendel’s paper is compelling. We are, however, reminded of the dangers that can arise from the selective use of quotations from original sources when offering our own interpretation of the material, of the importance of accurate citation, and the problems that the use of translated materials can present.
One final point is worth making. When Mendel published his paper in 1865 his decision to have just forty copies printed for distribution inevitably restricted both his potential audience, and the opportunity for access available to a wider audience. Today, thanks to the development of the world-wide-web and digitization we can all access Mendel’s papers. For historians, indeed all researchers, and the general reader, this is one of the great developments of our time. Libraries are wonderful places, and we can all agree with Caitlin Moran when she wrote that, “They are cathedrals of the mind; hospitals of the soul; theme parks of the imagination.”  But they have not been, and are not always easily accessible and many books are denied to the general public, locked away as they are in university and other institutional libraries and archives. The internet is changing, has changed, and will continue to change this. One day all the world’s knowledge may be available online, though much will continue to remain inaccessible due to pay-walls and other restrictions. When that happens we will all be able to cross reference Olby’s, The Origins of Mendelism, and Wichura’s, Die Bastardbefruchtung im Pflanzenreich. Of course we will also have to become fluent in German to make any sense of it.
A footnote on footnotes
Readers of this may well raise an eyebrow at my criticisms of Olby and Waller for poor referencing, noting that my previous posts aren’t exactly brimming with footnotes and bibliographic references. Hoist by my own petard, as the saying goes. I can only apologise and ask for your indulgence.
Allchin. Douglas. “Mending Mendelism.” The American Biology Teacher 62. no. 9 2000: 632-639.
Bateson, William. “The Facts of Heredity in the Light of Mendel’s Discovery.” Report of the Evolution Committee of the Royal Society 1 (1902): 125-160. http://esp.org/foundations/genetics/classical/holdings/b/wb-02b.pdf
Brannigan, Augustin. The Social Basis of Scientific Discovery. Cambridge: Cambridge University Press, 1981.
Callender, L.A.. “Gregor Mendel – an Opponent of Descent with Modification.” History of Science 26 (1988): 41-75.
Corcos. Alain. F.. and Floyd. V Monaghan. Gregor Mendel’s Experiments on Plant Hybrids – A Guided Study. New Brunswick. NJ: Rutgers University Press. 1993.
Darwin. Charles. The Origin of Species by Means of Natural Selection. or the Preservation of Favoured Races in the Struggle for Life. 6th ed. John: Murray. London. 1901. http://www.literature.org/authors/darwin-charles/the-origin-of-species-6th-edition/chapter-09.html
De Beer, Sir Gavin. “Genetics: The Centre of Science.” Proceedings of the Royal Society of London 164 (1965) 154-166
Edelson, Edward. Gregor Mendel and the Roots of Genetics. Oxford Portraits in Science Oxford: OUP. 1999.
Eiseley, Loren. Darwin’s Century. Evolution and the Men who Discovered It. London: Victor Gollancz, 1959.
Fisher, Ronald A. “Has Mendel’s Work Been Rediscovered?” Annals of Science 1 (1936): 115-137
Heimans, J. “Mendel’s Ideas on the Nature of Hereditary Characters. The Explanation of Fragmentary Records of Mendel’s Hybridizing Experiments,” Folia Mendeliana 6 (1971): 91-98.
Iltis, Hugo. Life of Mendel. Translated by Eden and Cedar Paul. New York: Hafner Publishing, 1966.
Mahajan, Deepti. “Gregor Mendel.” Encyclopaedia Britannica. Last updated May 8, 2013. http://www.britannica.com/EBchecked/topic/374739/Gregor-Mendel
Mendel, Gregor. “Experiments in Plant Hybridization 1865: Read at the February 8th. and March 8th. 1865. meetings of the Brünn Natural History Society. http://esp.org/foundations/genetics/classical/gm-65.pdf First published as “Versuche über Pflanzenhybriden.” Verhandlungen des naturforschenden Vereines in Brünn. Bd. IV für das Jahr 1865. Abhandlungen. 3-47
Mendel, Gregor. “On Hieracium-Hybrids Obtained by Artificial Fertilisation.” Mendelweb. http://esp.org/foundations/genetics/classical/holdings/m/gm-69.pdf First published as “Ueber einige aus künstlichen Befruchtung gewonnen Hieracium-Bastarde.” Verhandlungen des naturforschenden Vereines. Abhandlungen. Brünn. Bd. VIII für das Jahr 1869. 26–31.
Mendel, Gregor. “Ueber einige aus künstlichen Befruchtung gewonnen Hieracium-Bastarde.” in Versuche Über Pflanzhybriden. Zwei Abhandlungen 1865 and 1869 Von Gregor Mendel: Herausgegeben von Erich Tschermak Leipzig: Wilhelm Engelmann. 1901. 53. https://archive.org/details/versucheberpfla00tschgoog
Mendel, Gregor. “Letters to Carl Nägeli. 1866-1873: Gregor Mendel’s Briefe an Carl Nägeli. 1866-1873.” trans. by Leonie Kellen Piternick and George Piternick. MendelWeb. http://www.esp.org/foundations/genetics/classical/holdings/m/gm-let.pdf Originally published as Abhandlungen der Mathematisch-Physischen Klasse der Königlich Sächsischen Gesellschaft der Wissenschaften 29: 189-265. 1905.
Olby, Robert. “Mendel no Mendelian?” History of Science 17 (1979): 53-72.
Olby, Robert. The Origins of Mendelism. 2nd ed. Chicago. IL: University of Chicago Press. 1985
Sapp, Jan. “The Struggle for Authority in the Field of Heredity, 1900-1932: New Perspectives on the Rise of Genetics.” Journal of the History of Biology 16 (1983): 311-342.
Sapp, Jan. “The Nine Lives of Gregor Mendel.” In Experimental Inquiries. Edited by H. E. Le Grand, 137-166. Kluwer Academic Publishers. 1990. Reproduced online at http://www.mendelweb.org/MWsapp.html
Sclater. Andrew. “The Extent of Charles Darwin’s Knowledge of Mendel.” Georgia Journal of Science 61. no. 3 2003: 134-137.
Stansfield. William D. “Teaching Mendelism.” The American Biology Teacher 70. no. 6 2008: 345-349.
Stern, Curt, and Eva R. Sherwood, eds. The Origins of Genetics. A Mendel Source Book. San Francisco & London: Freeman & Co., 1966.
John Waller. “’The Priest Who Held The Key’: Gregor Mendel and the Ratios of Fact and Fiction.” Chap. 7 in Fabulous Science: Fact and Fiction in the History of Scientific Discovery Oxford: OUP. 2002.
Max Wichura. Die Bastardfruchtung im Pflansenreich. Erlautert and der Bastarden der Weiden Breslau: Morgenstern. 1865. https://archive.org/details/Wichura1865se59X
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What an epic post, Aaron.
I learned about Mendel in 5th grade, right before we planted some sort of bean in a Styrofoam cup to watch it sprout. My memory gets more and more vague the deeper it goes, but his experiments are one of the first facts I remember from any scientific field. Anything but the most rudimentary learning that came before it was forgotten.
Thanks Aaron. I started out with the intention of writing a 1,000 word bio piece on Mendel and somehow it evolved into a 3,347 word essay. Mendel and Pavlov are my first memories of specific scientists we were taught about at school. The other names I remember from school tend be engineers, Telford, Watt, Stephenson, Brunel, McAdam, Arkwright, etc., which thinking about it probably reflects my greater interest in history than science at the time.