Mabel Hokin and Salt Glands: My sad demolition of a biochemical treasure

Having worked on bird salt glands in Hong Kong I arrived at Babraham in October 1968 to work on the mammary gland and the mechanism of milk secretion—a very different gland and a very different fluid being produced.

During that summer Jim Linzell had attended a satellite symposium of the Washington Physiological Congress on exocrine glands and had heard Mabel Hokin give a talk on the bird salt gland. He told me about this and since a similar approach might provide information on the mechanism of secretion of the aqueous phase of milk, I set about doing similar studies on the mammary gland. However, when I read Mabel Hokin’s work in greater detail I realised there were some anomalies. I will not go into great detail but the concentrations of sodium, potassium and chloride ions in salt-gland slices appeared to be much higher than those reported by others. This mattered since by calculating the concentrations inside the cells from a knowledge of the size and composition of the extracellular space, she concluded that the high concentration difference of sodium chloride was established between blood and the inside of the cell, not between the cell and the lumen of the gland, as previous evidence had suggested. I, egged on by Jim Linzell and Richard Keynes FRS who was then Director of the institute and gathering information for his masterly review of ion transport mechanisms across membranes in different organs, thought it wise to repeat the Hokin experiments.

I was unable to get the same results as Mabel Hokin. The concentrations inside the cell appeared similar to other non-nervous tissues, implying that the high concentration gradient for salt is set up between the cell and the lumen of the gland, the later leading to the duct system and the flow of salt-rich fluid to the outside world.

The difference between mine and her results rested on the crude concentrations of sodium, potassium and chloride in the tissue, before any calculation of concentrations inside the cells. I did all sorts of studies with other tissues to see if the methods I was using gave results different from those reported by others. They didn’t. Were the salts being liberated from the tissue fully before analysis? Yes. I did all the standard tricks of analytical chemistry to check that when I added a known amount to the samples I recovered that same amount during analysis. Was I making a stupid arithmetical error in calculating the concentrations? I persuaded three colleagues to work through the calculations independently; they got the same answers.

I was—and still am—at a lost to explain how Hokin found such high concentrations of all three ions of interest. However, it is interesting that her concentrations in tissue were on average 1.94 times higher; double, in other words. Richard Keynes and I concluded privately that somewhere along the line Mabel Hokin had got her sums wrong by a factor of 2. In the days before spreadsheets and even before electronic calculators came into use, the chances of systemic error were increased. Keynes himself hogged the first computer (Olivetti Programma 101) to be installed at Babraham to recalculate some figures on ion movements across an epithelium or membrane originally worked on by a co-worker. ‘Well’, he said after his marathon session, ‘they were out by a factor of 10—100 in one direction and 1000 in the other’.

After the publication of my results, I sent Mabel Hokin an offprint but I received no reply. Her ideas on how the salt gland might work were not heard of again. But why was she working on the salt gland at all?

Mabel Hokin had a very interesting personal history as well as a key role in the uncovering of a major biochemical mechanism by which signals are passed within cells, even though she did not realise it at the time.

Sir Hans (then Professor) Krebs had an enviable reputation when he was at the University of Sheffield (before his defection to Oxford) of employing school leavers as technicians and then seeing the good ones through a university degree course and postgraduate research for a PhD. A number stayed with him as fully-fledged scientists for decades, or nested successfully elsewhere. Mabel Hokin was one of those school leavers.

Mabel Hokin the 1980s
Photograph used on Wikipedia

According to a potted biography on Wikipedia. Mabel Neaverson was born in Sheffield in 1924 to working-lass parents. Throughout her life she suffered from an autoimmune disease. After spending 1942-43 in the Land Army she joined the Krebs Cell Metabolism Unit as a technician in 1943. In 1946 she became an undergraduate student (funded at least in part by Sheffield Education Committee) and in the same year married her first husband, the actor, playwright, critic and university lecturer Dennis Davison* (1923-1994); he was also at the University and they met through her interest in costume design and the theatre. Her political activities at this time in the socialist society at university (Chairman, 1947-48) and as a member, with Davison, of the Communist Party of Great Britain were to have consequences a few years later. 

After graduation in 1949 (II(i) Hons. Physiology) Krebs suggested she should continue as a research student. Her supervisor was Quentin Gibson (1918-2011, FRS 1969) then in Physiology—apparently unhappily—at Sheffield. Her PhD, funded by the Medical Research Council) was awarded in 1952. I have only found one publication from that period which shows she was working on acetate metabolism in pigeon breast muscle.

As she started her PhD, Lowell Edward Hokin (1924-2018^†) was arriving in Sheffield from the U.S.A., accompanied by his first wife, to work with Krebs. Then, as the Wikipedia entry reads: ‘In a short time, Mabel met Krebs' graduate student Lowell Hokin, and the two began a romantic as well as professional relationship’. Divorces were obtained; they were married in Canada in December 1952 where they had arrived from Sheffield in April.

Rather than McGill University in Montreal, they had hoped to move from Sheffield to the U.S.A. but Mabel’s entry was completely blocked during the McCarthy era because of her communist party membership. 

In experiments started at Sheffield and completed in Montreal they found that when pancreatic slices were induced to secrete digestive enzymes by cholinergic neurotransmitters, radioactive phosphorus was incorporated at a greater rate into a chemical fraction of the cell they thought was RNA. However, the radioactive label was not in RNA but in the phospholipids of the cell membranes. Until then the phospholipids were ‘regarded as inert structural components of membranes’. Later, they showed the particular phospholipids that were labelled. The Hokins were the first people to demonstrate lipid turnover caused by the stimulation of receptors on the cell. The phenomenon became known as the ‘PI effect’.

The significance of the phenomenon they had discovered was not uncovered for some years. And this is where their own work took a turn in completely in the wrong direction. Because the PI effect was apparent in other organs when stimulated to secrete, they thought that the phospholipids must be involved in transporting substances across cell membranes. Because it occurred in organs like the newly-discovered salt gland which do not secrete enzymes they argued that their phenomenon must constitute the pump which needs energy to carry sodium across cell membranes. They erected a scheme called the ‘phosphatidic acid cycle’ which, they argued, carried sodium from one side of a membrane to the other. Their hypothesis received a great deal of publicity at the time with papers in Nature and Scientific American. But then their whole scheme fell apart. All sorts of evidence accumulated to show that their phosphatidic acid cycle did not fit the bill as a transporter of ions. The world moved on. But that is how Mabel Hokin came to work on salt glands. The announcement of the discovery of salt glands by Knut Schmidt-Nielsen in 1957 coincided with the Hokins seeking an organ that secreted sodium at a high rate and that was stimulated by cholinergic nerves.

Eventually, the ban on Mabel’s admission to the U.S.A. was lifted and the Hokins had moved from Montreal to the University of Wisconsin at Madison in 1957. This is not the place to describe their later work other than to point out that they were divorced in 1971, shortly after the work on the phosphatidic acid cycle as a transport mechanism was ended and the notion shot down.

The ‘PI effect’, however, took off, as described by Bob Michell FRS in his obituary of Mabel written for Biochemist shortly after her death in 2003:

Mabel and her scientific partner and ex-husband Lowell Hokin were amongst the few scientists who have initiated a new scientific field. Their work on stimulated phosphoinositide turnover in secretory tissues, most crucially in the 1950s and 1960s, was a slow fuse that finally ignited an explosion of work that made inositol phospholipids into star players in transmembrane signalling and many other cell regulatory processes. The extraordinary versatility of phosphoinositides would have come to light at some time without their work, but it is not clear how, and it would have taken much longer… 

It took another decade for the research community to realize that the initiating event of the Hokins’ ‘PI response’ is phospholipase C-catalysed hydrolysis of PtdIns(4,5)P2, which many cell- surface receptors harness as their central signal-transducing event. Later, 3-kinase-catalysed formation of PtdIns(3,4,5)P3 emerged as a second widespread signalling reaction, and a plethora of other roles for phosphorylated derivatives of PtdIns in central cell functions have since been uncovered. 

Mabel and Lowell Hokin laid the foundations on which all of these recent discoveries stand…She and Lowell never deduced exactly what their observations meant, largely because they were doing experiments that were ‘ahead of their time’, but those of us who followed could confidently use their beautiful results to develop new interpretations. 

Mabel was a gregarious and enthusiastic woman who never lost her North Country bluntness. Even when on crutches after having new hip joints, she would be dancing at a meeting party soon after coming off a long flight…

After I first read that I felt like I had shot Bambi.

The only photograph I have found of Mabel and Lowell Hokin at about the time they were working on
salt glands. A meeting in March 1966 on the Neural Properties of Biogenuc Amines

*Davison went to Australia in 1957 eventually becoming Senior Lecturer in English at Monash University in Australia.

†Lowell Hokin died last month (6 September 2018) in Colorado.

Hokin MR. 1967. The Na+, K+ and Cl content of goose salt gland slices and the effects of acetylcholine and ouabain. Journal of General Physiology 50, 2197-2209.

Hokin MR. 1969. Electrolyte transport in the avian salt gland. In, Exocrine Glands. Proceedings of a Satellite Symposium of the XXIV International Congress of Physiological Sciences. Edited by Botelho SY, Brooks FP, Shelley WB, p 73-83. Philadelphia: University of Philadelphia Press.

Keynes RD. 1969. From frog skin to sheep rumen: a survey of transport of salts and water across multicellular structures. Quarterly Reviews of Biophysics 2, 177-281.

Kresge N, Simoni RD, Hill RL. 2005. A role for phosphoinositides in signaling: the work of Mabel R. Hokin and Lowell E. Hokin. Journal of Biological Chemistry 280, e27.

Michell R. 2003. Mabel R. Hokin (1924–2003). Biochemist, December 2003, 62-63.

Peaker M. 1971. Intracellular concentrations of sodium, potassium and chloride in the salt-gland of the domestic goose and their relation to the secretory mechanism. Journal of Physiology 213, 399-410.

Through the Lion Gate. A History of Berlin Zoo by Gary Bruce. Oxford University Press 2017

Readers of books on the history of zoos are looking for different things. Some want a social history of a zoo and its place in the society of the day; some an account of the zoo in terms of its purpose at the time, i.e. the display of animals for education and/or entertainment and its breeding record; others an account of a zoo’s internal workings, architecture, policies and politics while others delight in a lighter story of individual animals and their relations with their keepers. This book falls firmly into the former camp. I can understand why that is the case because Berlin Zoo has a very dark history. It did not just exist during the Nazi regime—it was part of that regime and nearly completely destroyed as part of that regime.

The author has brought to bear his obviously great knowledge of the modern history of Germany on what is a thorough study of the history of Berlin Zoo and of how it came to have iconic rôle in the social life of the city. What makes the book even more remarkable is that the author ‘was not permitted to view documents held by Berlin Zoo’. I found that statement hard to take in, indeed I had to read the whole sentence twice. A respected academic historian of Germany was not given access to the Zoo’s archives is to me unfathomable and unforgivable. However, it becomes clear at the heart of this book that there has been an unwillingness to face up to what happened to the Zoo under the Nazi regime and the foul people involved in its running, including Lutz Heck, its Director. The emergence of their particular brand of eugenics, which ignored environment as a determinant of phenotype, is covered, if not in those terms.

The truth about Lutz Heck (1892-1983)^† was slow to emerge. In the 1960s, magazine articles describing his efforts to breed back the aurochs and wild horse by crossing domestic breeds with ‘primitive’ features made no mention of his past in the Nazi party or of his political responsibilities for nature, conservation and hunting in the conquered lebensraum to the east of Germany. Much has been made of his regime-supported but actually rather pathetic efforts to recreate for Germany the great wild beasts that occupied its original grasslands and forests. Heck’s efforts to educate and enthuse the young about the natural world, a trait common at the apex of the Nazi hierarchy, just goes to demonstrate that an interest in animals, their conservation, their protection and even bunny-hugging sentimentality—as well as a compulsion to control the lives of other people—can pop up right along the political spectrum from the loony left to the idiotic right.

Bruce also describes, at length, the displays, not confined to Berlin, of human natives of other parts of the world in regular exhibitions at the Zoo. These ethnographic shows brought in the crowds and the money (the Zoo was often short of money in the financial turmoil of the inter-war years) but there was no evidence that they were staged or visited because of any special feelings of racial superiority at the time. Curiosity about how other people lived seemed to be the motivation of the visitors, a curiosity satisfied in the 21st Century by well-paid-for in-situ demonstrations of traditional dancing, singing and village life to the passengers of visiting cruise ships from Shetland to Samoa.

There are parts of the book I did not find convincing. It seems impossible to escape the views of Harriet Ritvo in books about zoos written by professional historians. Her book, The Animal Estate, published in 1987 has been highly influential but I must say I disagreed then with much that she had written and I disagree with it now. In the early years, Berlin, along with other German zoos, was playing catch-up, particularly with London. Bruce falls into line with Ritvo in equating London Zoo’s history with its wish to display imperial superiority. This is not the place to argue the contrary but it is worth pointing out that the British Empire provided a network through which animals could be obtained. But London Zoo was obtaining animals from all parts of the world; the Empire had no monopoly on ‘new and curious objects of the animal kingdom’, just a whole lot of people riding the crest of the wave of interest in natural history that swept through Victorian Britain. It is also worth noting that the architecture of early- and mid-Victorian London Zoo was hardly imperial; modified domestic and garden buildings best describes the animal housing*.

A bonus to the book is the inclusion of the zoo built in East Berlin during the 1950s as a paean to the delights of communism.

It is difficult to criticise a book that has involved so much research across the whole history of Germany and Berlin. But I do object to some of the terminology, in particular the use of ‘euthanization’. Animals were killed. Full stop.

In conclusion I think this book will satisfy those involved in ‘human-animal studies’ but leave those seeking information on Berlin Zoo as a zoo wanting much more. Still to be answered are such questions as: how innovative and influential has Berlin been in advancing wild animal husbandry? How did the senior staff of Berlin Zoo, drawn, like Lutz Heck, from the descriptive academic zoology of the day, learn how to cope with the requirements of living animals—an entirely different sphere of activity?

†Not to be confused with his brother Heinz Heck (1894-1982), Director of Munich Zoo, who, as Bruce relates, did not join the Nazi party. He used one of the Zoo’s elephants to clear an overturned tram car left by the retreating Wehrmacht to slow the advance of American troops in 1945.

*Guillery P. 1993. The Buildings of London Zoo. Royal Commission on the Historical Monuments of England.

‘Go extinct' or 'Become extinct'

The week before last the pens of the retired admirals of Budleigh Salterton were spluttering their contents onto paper. The Times, in an obituary, had described H.M.S. Hood as a ‘battleship’. As every schoolboy knew, Hood, blown apart in that encounter with Bismarck and Prinz Eugen in the Denmark Strait on 24 May 1941, was not a battleship—she was a battlecruiser.

On a much lesser scale in the same week, there were those of us grating at the receipt of a society newsletter. Apart from the usual corporate managerialist claptrap on ‘strategies’ which divert so much effort from the organisation doing its real job, it contained the phrase: ’to stop wild animals going extinct’.

There have been discussions on ‘becoming extinct’ and ‘going extinct’. As numerous people have pointed out, there is nothing wrong with using the verb ‘go’ with some adjectives. However, ‘extinct’ is an absolute term; there are no shades of extinction, just like ‘complete’, ‘perfect’ or ‘certain’. Something can ‘become complete’, ‘become perfect’, ‘become certain’ or 'become extinct'; nobody, surely would write ‘go complete’, ‘go perfect’, ‘go certain’—or ‘go extinct’.

If I see or hear ‘go extinct’ again I will go mad.

Dodo by Roelant Savery (late 1620s)--before it became extinct

Ultraviolet Exposure of Insects and Vitamin D Synthesis. An intriguing study from 1934 is answered in 2018

Earlier in the year I was looking up articles in old magazines when I my eye shot towards a tiny snippet at the foot of a page:

VIOLET RAYS FOR MEALWORMS:—Reptile fanciers may be interested to learn that, according to a report in “The News Chronicle,” experiments have shown that live mealworms on which many of the Zoo animals are fed, prove far more beneficial if reared in artificial sunshine. (The Aquarist, March-April 1934, page 14)

The reason for my interest was that the finding implied that the mealworms kept under ultraviolet light were making Vitamin D. But insects do not synthesise Vitamin D; or do they?

I searched the scientific literature but could find no further information. The article in The Aquarist appeared on a page devoted to news from the Zoological Society’s Aquarium and ‘the Zoo” referred to is clearly London. I had no access to News Chronicle archives and put a copy of the intriguing report aside as ‘unsolved’.

For reasons that will become obvious further into this article, a few days ago I realised that the news from London Zoo would probably have appeared in a press release from the Zoo early in 1934 and that other newspapers could have carried the same story. The Zoo bombarded the newspapers of the day with stories about the animals, the keepers and the visitors. Some newspapers even had designated zoo correspondents such was the interest of the public in the Zoo and all its works. I searched the online British Newspapers Archive not expecting a great deal since its coverage is less extensive than was promised at its launch. However, my gloomy prediction was wrong. An article from the Daily Herald (12 January 1934) appeared on my screen:

VIOLET RAY MEALS AT THE ZOO

     Several of the animals at the Zoo are now having their food treated by artificial sunshine. Milk treated in this way is being given to the two orphan nilghaie antelopes recently born at the zoo. They are fed from the bottle twice daily in the presence of visitors. Experiments have shown that even live mealworms, on which many of the Zoo animals are fed, prove far more beneficial if irradiated. Monkeys fed on mealworms kept under ordinary sunless conditions were found to be more liable to rickets than those given mealworms reared in artificial sunshine.

In the 1930s Vitamin D and ultraviolet radiation were hot topics in research. They are also in the public eye. Rickets were a scourge and even in the 1960s a walk in the industrial cities of the north of England soon revealed reminders of its effect on the skeleton in the form of the bent legs of old ladies who, in those days, would not be seen dead in trousers.

The news report from London Zoo showed aspects of the research of the previous 20 years*. Ultraviolet irradiation of some human foods produces vitamin D, milk, for example. That would be the reason for exposing milk to UV lamps for feeding to young animals like the Nilgai. Was it supposed at the Zoo that the vegetable matter on which mealworms feed were producing Vitamin D and that the mealworms then ingested and retained the vitamin? Or did they think that the mealworms themselves were synthesising Vitamin D, like mammals exposed to sunlight?

I do not know then answer to these questions. A search of the reports in the archives of ZSL may provide some answers along with identifying whose idea it was to try ultraviolet irradiation of mealworms. My guess is that it was a continuation of the work of Sir Peter Chalmers Mitchell FRS and Joan Procter (who had died in 1931) who were interested in the practical benefits of ultraviolet light in improving the health of animals in the Zoo.

Mealworms, the larvae of Tenebrio molitor

The importance of ultraviolet and/or Vitamin D for reptiles in captivity has been recognised for decades. They, like mammals, can obtain their Vitamin D from their food or from synthesis in the skin exposed to ultraviolet. However, it was soon established that the common insects farmed for live food for reptiles, amphibians, birds, mammals and some fish had as well as low calcium a very low Vitamin D content. Supplements for reptiles have been provided by, for example, shaking a powder on their live insect prey or by putting minerals and vitamins into the insect’s food, thereby ‘gut loading” the soon-to-be-eaten insect. But, even then, special ultraviolet-emitting lamps still appear essential for the health of many species.

Having put the report in The Aquarist aside, I was astonished to see a paper published in July reporting that mealworms and other insects do synthesise Vitamin D when exposed to ultraviolet rays. In four insect species farmed in the absence of ultraviolet radiation, exposure to ultraviolet dramatically increased their vitamin D content. The effect varied between species but it is interesting to note that increases in both Vitamin D₃ and Vitamin D₂ (again with variation between species) were involved. The synthesis of Vitamin D₃ is characteristic of vertebrates; D₂ of plants, yeasts and fungi.

From Oonincx et al. 2018

The effect of ultraviolet was rapid, the concentration of Vitamin D₃ in mealworms (the larvae of a flour beetle, Tenebrio molitor) rising steadily during 8 hours of continuous exposure.

From Oonincx et al. 2018

The work of the Dutch-led team who did this research^† shows the practical benefit of ultraviolet irradiation of farmed insects for feeding wild animals in captivity as well as explaining reports of high Vitamin D₃ in some species of insects collected in the wild, i.e. exposed to sunlight. However, it raises as many questions as it answers. Previously, it has been argued that Vitamin D₃ is something special to vertebrates, closely involved in the metabolism of calcium and phosphorus needed for a bony skeleton. So what is it doing in insects? One sure bet is that it isn’t being produced for the benefit of vertebrate predators. And if it can be synthesised by insects what about other invertebrates?

Vitamin D₃ is just the precursor of the active molecule calcitriol, the synthesis of which includes several stages and different organs. Another key question is whether insects have the biochemical pathways to produce the molecule that is active in vertebrates. With that information it might be possible to infer whether Vitamin D in insects may be involved in those processes not concerned with calcium and bone in which it has been implicated, such as programmed cell death and innate immunity, in vertebrates. A whole new field of comparative endocrinology (the physiologically active form of Vitamin D is usually considered nowadays as a hormone) could be opening up.

Whatever the answers it is interesting that the work on ultraviolet irradiation of mealworms at London Zoo reported in the British press in 1934 was forgotten and only 84 years later has the question been raised again—and answered.

*Rajakumar K, Greenspan SL, Thomas SB, Holick MF. 2007. Solar. Ultraviolet Radiation and Vitamin D. A historical perspective. American Journal of Public Health 97, 1746-1754.

†Oonincx DGAB, Keulen P van, Finke MD, Baines FM, Vermeulen M, Bosch G. 2018. Evidence of vitamin D synthesis in insects exposed to UVb light. Scientific Reports 8:10807. DOI:10.1038/s41598-018-29232-w 1 

Crimson Finch - a beautiful Australian bird

I couldn’t resist taking video of Crimson Finches while birdwatching along the edge of Lily Creek Lagoon in Kununnura, on the eastern edge of the Kimberley in Western Australia earlier this year.

The Crimson Finch (Neochmia phaeton) occurs in tropical Australia and a small area of New Guinea. ‘Finch’ is of course a misnomer. It, along with all Australian ‘finches’ is an estrildid, like the waxbills of Africa. Seed forms the bulk of their diet but insects, as a richer protein supply, are taken in the breeding season. All the books say they occur along water courses and those in the video were in the thick vegetation surrounding the lagoon.

The males in particular were shining in the sunlight and were living up to their specific name of ‘phaeton’ - Greek for radiant or shining. Three subspecies have been defined and the ones we saw are in the range of N. phaeton phaeton.

Here is the distribution map of the species adapted from the late Derek Goodwin’s book, Estrildid Finches of the World, published in 1982 by the British Museum (Natural History):

Genomic signatures of human commensalism in House Sparrows; but what about urban Tree Sparrows?

News media have been reporting the results of a paper published recently on the genome of the House Sparrow (Passer domesticus)*. It is likely that commensal House Sparrows moved into Europe as agriculture spread. By comparing the genomes of a population of the species that is not commensal with ones from those that are, two distinctive signatures of positive selection associated with commensalism were found. One signature included a gene involved in development of the craniofacial region and skull the other a gene linked to starch digestion, as in, the authors noted, the domestication of dogs and the human population during the agricultural revolution of the Stone Age. It would appear that commensal House Sparrows adapted to eating cereal seeds.

Here's a male House Sparrow

Embed from Getty Images Male House Sparrow

Those of us who live or have lived in parts of Asia, will twitch a little at these news report because the commensal sparrow is not the House Sparrow but the Tree Sparrow (Passer montanus). That realisation often comes as a shock to birdwatchers from Europe who step out of their hotels in the heat of Hong Kong.

And here's a Tree Sparrow

Embed from Getty Images

So, if the authors of the paper on the genome of the House Sparrow extend their work to the Tree Sparrow would they find the same signatures of human commensalism? Anybody taking bets?

*Ravinet M, Elgvin TO, Trier C, Aliabadian M, Gavrilov A, Sætre G-P. 2018. Signatures of human-commensalism in the house sparrow genome. Proceedings of the Royal Society B 285: 20181246. http://dx.doi.org/10.1098/rspb.2018.1246 

Professor Harry Norman Green in a tragic aircraft accident in 1927, says Wikipedia. NO, it was a different Harry Norman Green, of the Royal Aircraft Establishment

In researching the story of Professor Harry Norman Green and his work on traumatic shock during the Second World War I came across an intriguing hit in a Google search of his name. The seemingly well-researched and referenced article on Wikipedia identified him as the Harry Norman Green who was involved in a tragic aeroplane accident in 1927. However, a little more research shows this was NOT ‘our’ Harry Green, then clinical assistant to Dr (later Sir) Edward Mellanby, Professor of Pharmacology in Sheffield, but somebody else of the same name, in his case a scientific civil servant who developed techniques for navigation and safer night flying in the 1930s.

Western Daily Press
14 November 2007
British Newspaper Archives

In short, on 9 November 1927, Flying Officer Campbell Mackenzie-Richards, the pilot of a Bristol F2b fighter, was flying in the dark from Croydon aerodrome, where he had been testing experimental navigation equipment, to the Royal Aircraft Establishment at Farnborough. He had a defective compass and could find neither Farnborough nor, on turning back, Croydon. By then he was low on fuel and  told his observer to bail out using a parachute; this the observer did and landed safely. The pilot, however, was killed, with parachute apparently open, after he jumped at, it was believed, too low an altitude. The plane crash a short distance away. Mackenzie-Richards, a well known test pilot and air race competitor had been married for only three months; he left an unborn daughter.

The observer who landed safely was Harry Norman Green. I do not know how the writer of the Wikipedia article (also picked up and reported elsewhere including here) equated this Harry Green with Dr (later Professor) Harry Green. A quick perusal of the newspapers reporting the accident and the inquest clearly indicate they were not one and the same. At the inquest the observer ‘said he was a Technical Officer in the Royal Air Force and had been in the service for two years’ and that he was a ‘a technical officer at the same establishment’ (i.e. Farnborough). This was obviously not Dr Harry Norman Green of Sheffield.

Records available online about Farnborough and the RAF show that Green was an expert in lighting for airfields. In 1932 he produced a report for RAE on the atmospheric transmission of coloured light. He applied for a British patent for his ‘Improvements in or relating to navigation lights’ in 1934. Earlier, in 1930, he published with A.K. Toulmin Smith BA AMIEE “Marking the Modern Air Route: The Lighting of Civil Air Routes and Aerodromes for Night Flying Considered in the Light of Modern Development”*. Both authors were shown as Scientific Research Staff at the Royal Aircraft Establishment at Farnborough. He is also mentioned in the Meteorological Magazine of March 1957 for proposing a technique using flares to measure visibility on airfields.

Further evidence, were any required, is that a Harry N Green was shown in the 1939 Register living with his wife and children at 134 Victoria Road, Farnborough as a ‘Senior Scientific Officer, R.A.E.’. This Harry N. Green’s date of birth was 13 March 1891. A family tree on ancestry.com indicates this was his second wife, his first wife having died in 1932.  In the 1911 Census he is listed as an electrical engineer living in London He was born in Grasmere, now in Cumbria, and died in Surrey in 1967, aged 76, the same year as Professor Harry Norman Green.

Now how do I tell the author of the Wikipedia article on Mackenzie-Richards and his tragic death that he/she got the wrong Harry Norman Green as the observer in the aircraft?

*To enable aircraft to compete with other forms of transport, on a commercial basis, it is essential that services should be run during the hours of darkness. With this end in view the development of night flying facilities has received considerable attention in recent years, and it has been conclusively proved that, when multi‐engined machines are flown over an adequately lighted airway, night flying is both safe and reliable. In the United States, where aircraft are extensively used for carrying mails, more than 15,000 miles are flown every night under all conditions of weather.