Bless you, Blackley! Darwin inspires pioneering hay fever researcher

You may not have heard of Charles Harrison Blackley (1820—1900), but if you are one of the 15 million people in the UK who suffer from hay fever, you are indebted to him. For it was he who identified pollen as the cause of the allergy, and not dust, ozone, benzoic acid and light and heat— just some of the theories in existence towards the end of the nineteenth century.



Darwin was very interested in hay fever. On 14 June [1873] he wrote to Blackley to thank him for his book Experimental researches on the causes and nature of Catarrhus Aestivus (hay-fever or hay-asthma). And on  5 July 1873 Darwin wrote again, saying:  ‘The power of pollen in exciting the skin & mucous membrane seems to me an astonishing fact’.


Blackley was a doctor, practicing in Hulme, Manchester, who advocated controversial homeopathic treatments that were scorned by the medical establishment.  Himself a hay fever sufferer, Blackley devised an ingenious series of self-experiments to ascertain the cause and mechanism of hay fever.  It was by exposing himself to possible causative agents, and observing changes in his own symptoms, that he was able to single out pollen as the only credible cause.


Graph from Blackley (1873)


Blackley investigated pollens from over 80 different types of plant and concluded that grasses caused the greatest reaction. He also experimented with fresh, dry and extracts of pollen, administered to his nose, mouth, eyes and scarified skin. Boiling and dialysing fever-inducing pollen did not reduce its effects. Darwin wondered if the pollen would become harmless, if subjected to dry heat above the boiling point of water.  He also asked Blackley why he had not considered the distinction between plants fertilised by the wind (entomophilous) and those fertilised by insects (anemophilous).  Darwin writes:


Perhaps where grass is cut & dried; some pollen of the entomophilous division may be blown about; but naturally hardly any would thus be blown. Whereas the pollen of anemophilous plants cannot fail to be largely blown in every direction. (Letter to C. H. Blackley, 5 July [1873])


Blackley wrote back on 11 July 1873 that the distinction had ‘a very important bearing upon the subject, and I very much regret that it should have escaped my attention’. He excused himself for the oversight, explaining that ‘investigations have had to be made with the hourly recurring demands of a moderately large practice pressing upon me’.


Diagrams of air sampling devices, from Blackley (1873)

Darwin was fascinated by Blackley’s experiments testing whether pollen could be carried large distances in the upper regions of the atmosphere.  Blackley wrote on 7 July 1873 that his high altitude experiments had been inspired by Darwin’s discussion of collecting atmospheric dust at Porto Praya in his Journal of researches (2nd edition, p. 5). Darwin gave a further example of how coniferous pollen could be carried for hundreds of miles in the upper atmosphere and be deposited on ships— explaining why some sailors suffer from hay fever out at sea.


Diagrams of clockwork mechanism to expose slides, from Blackley (1873)

Blackley flew kites at different altitudes with sticky slides on them to sample the air. He perfected the experiment by adding a clockwork mechanism to expose the slides for a set time, and enhancing the glycerine sampling solution with carbolic acid to deter insects.  He concluded that in pollen seasons much higher levels were found at 1000-2000ft than at ground level, and this explained why people suffered from hay fever in large cities far away from sources of pollen.


In his later work, possibly inspired by his interest in homeopathy, Blackley tried to find out the smallest amount of pollen that would initiate and maintain the symptoms of hay fever.  This required determining the weight of pollen grains by a dilution method.  In his letter of 9 March 1877, Darwin wrote: ‘Your calculation of the (weight) of pollen grains is wonderful’.


The ultimate goal of Blackley’s research remained elusive.   He wrote to Darwin on 11 July 1873:


The problem of cure has still to be solved and really resolves itself principally into a question of prophylaxis. I fear it will prove to be the most formidable and difficult part of the task I originally set myself.


Blackley tried many drugs to no avail. He had slightly more success experimenting with air filtration systems, and in recommending spending summers in suitable locations to avoid pollen.  But his lasting contribution to the science of allergy was to establish the link between hay fever and pollen, through inventive— and self-sacrificing— experiment, and thorough and detailed observation and description.

New Darwin and Emotions Resources

Expression, Fig. 21 (Horror)

Darwin’s work on the expression of emotions began with observations he made on the Beagle voyage.  After almost 40 years of collecting data (including observations of his own children) and thinking about the conceptual issues, he originally intended it to be published as a chapter of Descent of Man (1871). However, Darwin soon realised that this would not do the topic justice.  He abandoned the chapter and, after Descent was published, he put the wealth of material that he had gathered together from all over the world into the monograph The Expression of the Emotions in Man and Animals (1872).


One of the sources of evidence in Expression was the responses to the expression questionnaire that Darwin began sending out to correspondents across the globe from 1867. Its purpose was to gather information on the emotional behaviour of non-Europeans.  We have added a commentary and collated the replies to the questionnaire in interactive map and table form here.


During our recent work on emotions, we have collaborated with the Autism Research Centre and the Cambridge Computer Science Laboratory. We held a Face of Emotion event in which Darwin’s work on expression was discussed in the context of current research in artificial intelligence, autism, and neuroscience. You can listen to the short talks given here.


These new resources are in addition to Darwin’s notebook of observations on children, and an online recreation of the emotion experiment that Darwin carried out with Benjamin Duchenne’s photographs, with family, friends and other visitors to Down as his subjects.

Darwin and Human Nature Conference – Cambridge, 19-20 April

We’re busy preparing for our Darwin and Human Nature Conference on 19 and 20 April 2012. It will be held at CRASSH (The Centre for Research in the Arts, Social Sciences and Humanities), University of Cambridge.


The conference will examine the series of intersecting boundaries that have defined the human from the mid-19th century to the present:

• human/animal

• civilized/savage

• woman/man

• mind/machine

• nature/culture.



We’ll be looking at how different disciplines have constructed and contested these boundaries, and reflect on the legacy of Darwinian frameworks of the ‘human’ today.


Convened by Dr Paul White, Dr Sophie Defrance and Professor Jim Secord, speakers will include:

  • Gillian Beer (English, Cambridge)
  • Carolyn Burdett (English, Birkbeck)
  • Tim Crane (Philosophy, Cambridge)
  • Sophie Defrance (DCP, Cambridge)
  • John Dupré (Philosophy, Exeter)
  • David Feller (HPS, Cambridge)
  • Phillipa Levine (History, University of Texas, Austin)
  • Tim Lewens (HPS, Cambridge)
  • Francis Neary (DCP, Cambridge)
  • Sadiah Qureshi (History, Birmingham)
  • Angelique Richardson (English, Exeter)
  • James Secord (HPS, Cambridge)
  • Roger Smith (History of Science, Moscow)
  • Kathryn Tabb ( History and Philosophy of Science, Pittsburgh)
  • Paul White (DCP, Cambridge)
  • Catherine Wilson (Philosophy, Aberdeen)
  • Elizabeth Wilson (Women’s Studies, Emory University)

Location: CRASSH, Alison Richard Building, 7 West Road, Cambridge CB3 9DT


See the conference programme and register here


Emotions and Interpretations: Responses to the Darwin Online Emotions Experiment

Thanks to all who took part in our online emotions experiment – over 18,000 of you! The formal stage of the experiment is now over, but it will be staying online as an activity, so if you don’t want to know the results, look away now.  If you’d like to find out more about the experiment, or have a go yourself, click here.


We promised to give some feedback and so here is what we made of the results.  We’ve summarised the top 20 responses to each photograph in the pie charts below.


We have left related words in the survey, so as not to put our own interpretations on what constitutes a similar enough word to be grouped together into the same emotion.  Your responses to each of the Duchenne photographs were processed in exactly the same way but, as with Darwin’s original experiment with colleagues, friends and family members in March to November 1868, the experiment is hardly scientific by modern standards.


We did however have a much larger number and broader range of test subjects than Darwin. Darwin only tested 23 English men, women and children of different ages and, although completely anonymous, we are assuming that our responses came from all over the world. Though Darwin’s subjects were all middle class Victorians, they probably found it easier to identify these highly stylised depictions from their experiences of Victorian theatre.


For us, the interest in the experiment was not so much in the results as in the process of taking part, and in learning more about the context of Darwin’s studies of expression and the methodological problems he faced. The main aim was to give a sense of what it was like to participate in an experiment in Darwin’s day.


What we can say is that the responses to each photograph were extremely diverse. This reflects Darwin’s conclusion that some of these artificially-created facial expressions convey a particular emotion more convincingly than others.  For instance, over 50% identified photographs 2 (surprise), 3 (terror), 4 (grief and despair) with the correct or very similar emotion, and over 25% of you identified photograph 1 (laughing) with a happy-type of emotion. Click on the pie charts to see larger versions.



However, for the perhaps more complex emotions depicted in photographs 5 to 11, hardly any of the participants identified the exact emotion and there was a greater range of, often conflicting, interpretations. This was true of Darwin’s subjects as well. Clearly some of the top answers are words that have some relation to the intended emotion but the level of disagreement is much more marked. This is especially apparent with photographs 6 (crying from grief), 8 (suffering), 9 (deep grief) and 11 (hardness) where the proportion of ‘other’ responses is between 40% and 60% of the total. With photographs 5 (agony, torture and fright) and 10 (fright with agony) there is a broad level of agreement on the general type of emotion and, equally, with photograph 7 (half face crying, half laughing) people were generally half right in identifying the face as depicting a happy-type emotion. Click on the pie charts to see larger versions.



The average response times ranged from 4 to 16 seconds, indicating that people did not think about the photographs for a long time. This is broadly in keeping with Darwin’s conclusion that ‘many shades of expression are instantly recognised without any conscious process of analysis on our part’ (Expression, p. 360).  People looked at the compound emotions for the longest time on average (e.g. half face crying, half laughing -16 seconds; crying from grief – 12 seconds; grief and despair – 8 seconds) before making a decision.  They also looked at photograph 11 (hardness) for 9 seconds, possibly because this would no longer be identified as an emotion. This illustrates the point that the repertoire of emotions may change over time in different historical contexts; as does the top response to photograph 9 ‘bored’, which is unlikely to have been seen as an emotion in Victorian times.


Darwin was surprisingly inventive in developing this and other methods (like the questionnaire) and the experiment was innovative for its time. He was self-critical, revising his methods as he went along, and doubtful about what his results could show. Some uncertainty remains today, especially questions about the ability of language to describe emotions, and problems with synonymy and the categorisation of emotions. Finally, the experiment shows how difficult it is to identify emotions from static images, which is why modern experiments use video to show more context (such as tone of voice and body posture) and change in expressions over time.


You can find the experiment, background context and Darwin’s results at:


The Darwin Correspondence Project’s Paul White is doing an interview this week on the experiment for the Australian radio programme Future Tense.

You too can be Darwin’s guinea pig

Imagine going to dinner with Charles and Emma Darwin and, the minute you get through the door, being dragged off by the famous scientist to take part in one of his experiments. That is exactly what happened to a series of visitors between March and November 1868 when Darwin was researching for his book The Expression of the Emotions in Man and Animals. You can take part in an online recreation of the experiment combining 21st century techniques with Darwin’s own test materials, developed as part of our ‘Darwin and Human Nature‘ research programme.


We can get a very good idea of what was going on from surviving letters and manuscripts – it’s an exciting, and perhaps surprising, close-up view of Darwin at work surrounded by family, friends, and colleagues, all of whom get involved. One visitor described what happened:

Mr. Darwin brought in some photographs taken by a Frenchman, galvanizing certain muscles in an old man’s face, to see if we read aright the expression that putting such muscles in play should produce

– the guests admitted that they’d all gone off afterwards and made faces at themselves in the mirror. That visitor was Jane Gray, wife of the Harvard botanist, Asa Gray; you can also find out more about Jane’s correspondence with Darwin, and read the full text of the charming letter in which she describes her stay.


The photographs were from a book by the physiologist, Benjamin Duchenne, whose claim to be able artificially to simulate convincing expressions using electrodes Darwin wanted to test. The eleven black and white photos he used – and that we reuse in the online test – have a bit of a ghoulish quality. Both Duchenne and Darwin were keen to stress that the people in them weren’t in pain – well, OK, not much – but when Darwin later reproduced some of them in Expression he had two engraved with the electric probes left out – a nineteenth-century version of photoshopping.


Darwin was investigating the claim that our ability to express emotion is evidence of our separate creation; he argued that most human expression is innate, with shared expressions being evidence of the common descent not just of all human races, but of humans and other animals. This experiment, part of his wider research programme, was not a scientific experiment as we understand it today: there was no control group, the experimental materials were not consistent across the whole trial, and he used a very small number of test subjects by modern standards, but this was pioneering work in a field where methodology is still a thorny issue. We hope recreating his experiment will get people thinking about some important and intriguing questions: Are there core emotions? What are they and how many? Why do we express emotion in the way we do? How do we recognise it and can we be sure we all mean the same things? Is the expression of emotion innate? Or is it culturally modified? How do we equate different words to describe emotion? Can a static image ever convey emotion accurately?


Darwin claimed that he had not led his witnesses, but that the photographs had been tested by “showing them to many persons without any explanation and asking what they meant”. This would be described today as a “single-blind” test, Darwin’s tables of results – which you can also see on the website – show that actually he was refining his method as he went. The tables aren’t dated, but we worked out their order by matching the sequence of visitors with references in letters and diaries. The first batch of visitors saw only seven of the eventual set of eleven photographs, and the first few responses consisted of “yes/no” answers, suggesting that, rather than asking what the expression was, Darwin had asked simply whether the photographs showed what they were supposed to.


We showed the tables and the original photographs to two other Cambridge groups whose work builds on what Darwin started – one at the Computer Lab teaching robots to recognise human expressions, and the other at the Autism Research Centre, where Professor Simon Baron-Cohen and his team use brain imaging in studying recognition of emotions. Darwin’s tables are roughly drawn on rather scrappy bits of paper – pioneering science in a field that now uses MRI scans and supercomputers started with nothing more than basic materials and a sharp mind. The three groups have begun a collaboration, launched this Saturday at Cambridge University’s Festival of Ideas – the UK’s only festival covering the arts, humanities and social sciences. The 21st century Darwin experiment uses a format developed by the Computer Lab and shows Darwin’s photographs alongside some of the video clips of the Emotions Library developed by the ARC.


We don’t know what Darwin’s selection criteria were for his test subjects, or even if they were volunteers, or conscripts. In the middle of conducting his experiment Darwin went off for a family holiday to the Isle of Wight where he was introduced to the poets Tennyson and Longfellow – its a pity he didn’t ask them what they thought.

La Machanga del Agua Mansa

La Petite Lune, 1871

How much like a monkey is a person? Did our ancestors really swing from trees? Are we descended from apes? By the 1870s, questions like these were on the tip of everyone’s tongue, even though Darwin himself never posed the problem of human evolution in quite these terms. Nevertheless, his Descent of Man (1871) dealt directly with human origins, and it opened the floodgates in Victorian society for all kinds of speculation—from the scientific to the outrageous—into the nature of human evolution. In particular, evolutionary oddities—what might have been called “freaks of nature” at the time—generated a great deal of interest and supposition.  And Darwin, with his wide and varied network of correspondents, was well placed to receive accounts of these cases in his postbox.

One such account came in a letter from a Venezualan-born American named Benjamin Renshaw. In June of 1872, he wrote to Darwin about a local girl living in a mountain town on the island of Tenerife. Clearly “the offspring of a man & woman,” she “so much resemble[s] a monkey, that she is called ‘La Machanga del Agua Mansa,'” or “the Monkey of Agua Mansa.” Bold enough to write to Darwin despite their lack of acquaintance, Renshaw described the monkey-girl in as much detail as he could, convinced that it would be more than a mere curiosity to Darwin, but of actual scientific interest and use.

“The head of the machanga is small & her body is thickly covered with hair. Her mode of scratching herself with upturned hands, of throwing things over her shoulder; her passion for climbing trees, & her ways & habits generally resemble those of a monkey. Her hands & feet are more like the human hand & foot, only the fingers & toes are unusually long. She is very shy, but is easily allured by the sight & smell of food; she speaks only in inarticulate sounds, & is at times quite savage.”

Juliana Pastrana, from Hutchinson et al, The Living Races of Mankind (London, 1900)

Juliana Pastrana, from Hutchinson et al, The Living Races of Mankind (London, 1900)

Unusually hairy people have often been the subject of popular scrutiny. Think of the quintessential side-show—the bearded lady—guaranteed to draw a crowd at any circus, fair, or public show. (Darwin even referred to one of the most famous bearded ladies in history, Juliana Pastrana, in the second volume of Variation, although it was for her unusual dentition rather than her hairiness.) Public exhibition, Renshaw feared, was the likely fate of La Machanga:

“I suppose she will be victimized one of these days by some enterprizing Barnum, & I have no doubt he will make a good thing of it.”

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Monkeys Attracted to Humans, but do they Kiss and Tell?

In recent posts, we’ve explored the implications of cross-species sexual attraction, and the perception of language as a measure of distinction between Homo sapiens and the rest of the animal kingdom. The question of what separates our species from other animals, and whether language is indeed a mark of distinction, continues to fascinate, intrigue and trouble today, just as it did in the 1870s. These two issues–of cross-species selection and language acquisition–came together following the publication of Darwin’s Descent of Man in 1871 in the search for the so-called “missing link” in human evolution.


As a famous figure in the debates surrounding human evolution, Darwin could be something of a lightning rod for eccentric thinkers with their own ideas about his theories. The idea of a “missing link” compelled one such enthusiast to write to him about the possible origins of humankind. Having read an “exposition of the ‘Darwinian theory’” that posited the missing link as an extinct “race of ‘Speechless Men,’” an American banker living in Paris by the name of William B. Bowles suggested to Darwin that, in fact, the “missing link” was neither speechless nor extinct. Rather, the “missing links” in human evolution were “Speaking Monkies,” and Bowles was bold enough to suggest that he thought he could “point out this missing race, show where and how it lives.” Continue reading

Rubicon crossed?

Hugo Rheinhold, "Ape with Skull", by Darwin Monkey

Hugo Rheinhold, “Ape with Skull”, (Darwin Monkey)

A long-standing debate concerns whether humans are specialized for speech perception ; in the the second half of the nineteenth century, two of the primary figures in this debate were Charles Darwin and Friedrich Max Müller.


A distinguished scholar and one of the leading figures of Victorian cultural life, Müller stated that language was a “Rubicon” between man and brute. Müller specifically attacked the ideas Darwin had formulated about languages in the Descent of Man, where Darwin had rejected Müller’s ideas about Man’s special place in evolution. The difference of opinion led to a series of letters  between the two men of science.


The recent findings of an experiment published in the journal Current Biology could, however, prove to be further evidence that Darwin was right.


Some researchers argue that the capacity for language acquisition is demonstrated by the ability to understand synthetic speech, incomplete or distorted spoken words. Lisa Heimbauer and her colleagues Michael Beran and Michael Owren, from Georgia State University in Atlanta tested a chimpanzee, which had been raised by humans and spoken to as if she were human, to find out whether she too could recognise incomplete or distorted spoken words. The talented chimp, named Panzee, recognised degraded spoken words far more often than should have been the case by chance, providing evidence that our common ancestor would have had the ability to perceive speech.


So has the Rubicon been crossed?


Lisa A. Heimbauer, Michael J. Beran and Michael J. Owren, A Chimpanzee Recognizes Synthetic Speech with Significantly Reduced Acoustic Cues to Phonetic Content, Current Biology,  Available online 30 June 2011.
 Matt Walker Editor, BBC Nature, “Chimp recognises synthetic speech”

Too Human in Nature?

The human-like qualities of great apes have always been a source of scientific and popular fascination, and no less in the Victorian period than in any other. Darwin himself, of course, marshalled similarities in physiology, behaviour and emotional expression between Homo sapiens and other simians over the course of his long career to support his views on evolution. This kind of evidence appeared in many of his publications, notably The Descent of Man and  The Expression of the Emotions in Man and Animals.  But were some parallels between human beings and other great apes too disquieting to use as scientific evidence?


Correspondence between Charles Darwin and Gaston de Saporta, a French paleobotanist, suggests that this may indeed be the case. In 1872, de Saporta wrote to Darwin after reading Descent of Man. In a long letter in which he both praised the work and expressed his opinion that Darwin may have argued for too close a common ancestry for man and monkey, de Saporta identified two key pieces of evidence which he believed showed most strongly the commonalities between humans and apes: dentition, which “seems to denote an exclusive link with the Monkeys of the old continent,” and “female menstruation and, as a corollary, the odour which makes women attractive to many monkeys.”


In his reply, Darwin graciously thanked de Saporta for “the trouble which you have taken in giving me your reflections on the origin of Man.” Promising to reflect on de Saporta’s comments, he nonetheless stood his ground:

I cannot at present give up my belief in the close relationship of Man, to the higher Simiate. I do not put much trust in any single character, even that of dentition; but I put the greatest faith in resemblances in many   parts of the whole organization, for I cannot believe that such resemblances can be due to any cause except close blood-relationship.


It’s no accident that Darwin did not acknowledge de Saporta’s point about menstruation or its corollary—the attractiveness of human women to other apes. Darwin’s difficulty negotiating this issue had much to do with norms of Victorian respectability, and what was or wasn’t appropriate for wider circulation beyond private correspondence or, for publication.

Punch cartoon, with reference to cross-species sexual attraction

From Punch 24 May 1873

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Spotlight on a correspondent: William Winwood Reade

On May, 19, 1868, an African explorer and unsuccessful novelist, William Winwoode Reade (1838–1875) offered to help Darwin, and started a correspondence and, arguably, a collaboration, that would last until Reade’s death.

After a first 1861 tour of West Africa, in which he paid particular attention to arguments then current about the character of gorillas and the existence of cannibalism, Reade had been associated with the Anthropological Society, which at the time mostly represented those who disagreed with Darwin’s theory and advocated the separate creation of the human races, and opposed the monogenist views of the Ethnological Society.

Nonetheless, Reade contacted Charles Darwin in 1868 to offer his services: his second expedition to Africa was conceived, at least in part, as a scientific venture. Darwin drew on this information in the Descent of Man. In turn, describing himself as a “disciple” of Darwin, Reade claimed inspiration from the Origin of Species (“your book – The Origin- has had considerable influence on my mind. If I read it earlier in life it might have completely changed the course of it – Winwood Reader to Charles Darwin, 31 January 1871) and sought Darwin’s advice on the passages about the origin of language which he intended to publish in the Martyrdom of Man. Reade’s reputation as a writer rests not on his novels, nor on his travel writing, but on that single work, first published in 1872. The Martyrdom be quoted as an essential book by HG Wells, George Orwell, and, even, Sherlock Holmes. People are sometimes surprised to find from his correspondence that Darwin worked so collaboratively, but this is just one of many examples drawn from his international network [link to the other post here]. The Darwin and Human Nature Project will be making some of the most significant of Reade’s letters available online ahead of their publication in the print edition of the Correspondence – a fascinating glimpse into the construction of Descent and into the warring beginnings of two sciences, ethnology and anthropology, as understood by an avowed Darwinian free-thinker.

For more about William Winwood Reade, see

Felix Driver, Geography Militant, Cultures of Exploration and Empire, (Blackwell, 2001)

Felix Driver, ‘Reade, William Winwood (1838–1875)’, in Oxford Dictionary of National Biography, (Oxford University Press, 2004); online edn, May 2009.