Friday 27 November 2020

Selecting Good Students: Sherrington’s Frog Test

The second paragraph of Sir Vincent Wigglesworth’s (1899-1994) biographical memoir for the Royal Society reads:

His father was imaginative, encouraging his children to collect material for demonstrations such as the microscopic life in a drop of pond water or the circulating corpuscles in the web of a frogs foot. Many years later, V.B.W. mentioned the fascination of the frog preparation to Sir Charles Sherrington, then living in Master’s Lodge at Caius. He said he used it as the ‘acid test’ for identifying research students. Less dedicated students glanced down the microscope and passed on, but future ‘physiologists’ were unable to tear themselves away from the view of blood cells bustling along capillaries. 

I am delighted to report that I unknowingly passed Sherrington’s test too. I was given what was little more than a toy microscope around the age of fifteen and was transfixed first by watching the blood circulation in a tadpole’s tail and then a frog’s web.

An old school friend dug this out of his loft
before moving house earlier this year. We had
identical microscopes made by J & L Randall
under the trading name of SEL (Signalling
Equipment Ltd). The magnification was fixed
at 100x. My father made a case for both of us
but mine along with the microscope have long gone

Sir Charles Sherrington (1857-1942)
(Wellcome Images)

I looked for a good demonstration on YouTube or in commercial libraries; they can be found with a simple Google search. However, I was disappointed since the magnification used is sometimes too great and the ability to rack the focus up and down is missing. The extraordinary contortions of the red cells are evident as well as some of the jostling as vessels branch. But there is nothing like the real experience.

In the Wellcome Library’s collection I did find an old gem, made in 1923, shot in black-and-white. One of the photographers was August Krogh (1974-1949), the Nobel Laureate famous for his work on control of capillary circulation. 

Liddell EGT. 1952. Charles Scott Sherrington 1857-1952. Biographical Memoirs of Fellows of the Royal Society 8,  241-270

Locke M. 1996. Sir Vincent Brian Wigglesworth, C. B. E., 17 April 1899 - 12 February 1994. Biographical Memoirs of Fellows of the Royal Society 42, 541-553.

Sunday 22 November 2020

Herpetology in Britain: The Trio of Medical Men—Smith, Bellairs and Frazer

A fact, noted in a biography of one of them, is that all three authors of the editions of
The British Amphibians & Reptiles and its successor in the Collins New Naturalist Series published from 1951 onwards were medically qualified

There was very little academic interest in reptiles and amphibians in Britain. Yes, of course, there were the famous herpetologists at the Natural History Museum in London but their interests in the 20th century were taxonomy and systematics, again not of burning interest to the biologists of the day. And there were those using amphibians to study developmental processes and basic physiology for which the frog is ideal. Comparative studies also included reptiles and amphibians but generally only en passant. Famous British palaeontologists devoted much of their lives to reptiles and amphibians but of the physiology, behaviour and ecology of living forms there was virtually nothing. Thus in a directory of research in British universities in 1960-61, only three individual entries refer to research in herpetology (other than a very specific interest in, for example, the structure of a particular organ) or developmental biology. They were: Angus Bellairs at St Mary’s Hospital (reptilian anatomy), London, Eric T.B. Francis in Sheffield (reptilian physiology) and C.L. Smith in Liverpool (amphibian physiology).

I think there are two reasons why research on reptiles and amphibians in Britain was not a topic of interest in the universities. The first is obviously the sparsity of species. The second is that research solely on one group of vertebrates, as opposed to a wider comparative approach, might have seen to have been unimportant in that there were unlikely to be discoveries made of wide biological significance. Whatever the reasons, it is not surprising that the major advances in reptilian ecological physiology, particularly thermoregulation, were made in the U.S.A. in the middle years of the 20th century where there is a rich herpetofauna and considerable academic interest.

The man who pulled all the information of British amphibians and reptiles together, including that gathered by very gifted amateur naturalists in Britain as well as in continental Europe, was Malcolm Arthur Smith (1875-1958). He was keen on amphibians and reptiles as a child but knew the only way he could pursue that activity was by earning a living as a doctor. After qualifying at Charing Cross Hospital and practice in London he went off to Bangkok as medical officer to the British Legation. That job was then extended to physician to the royal household. During his time in Siam, now Thailand, he was active in natural history, collecting specimens and writing accounts of the herpetofauna of south-east Asia. In 1925 at the age of 50 he retired to London where he was given space at the Natural History Museum. From there until his death he published extensively particularly on the reptiles of south and south-east Asia. From its founding in 1947, Smith was president of the British Herpetological Society. It was when he was over 70 that he turned to the British herpetofauna again, with the first edition of the New Naturalist volume appearing in 1951.

Angus d’Albini Bellairs (1918-1990) was co-editor of the fifth edition onwards of Smith’s New Naturalist book. Keen in reptiles as a boy he included zoology in his pre-clinical medical course at Cambridge. After qualifying in medicine from University College Hospital, London, he served in the Royal Army Medical Corps in north Africa, Italy and Burma, collecting reptiles throughout and sending preserved specimens back to London. After the war he published two papers with Malcolm Smith. One, on the head gland of snakes, read to the Linnean Society in 1944, must have been the result of work done while he was a medical student or while he was still in the army; the material was mainly that collected by Smith in Siam before 1925. The second paper, published in 1953, was on the egg-tooth of snakes. By that time he had been appointed lecturer in the anatomy department at the London Hospital medical school by James Dixon Boyd (1907-1969) who had been one oh his lecturers at Cambridge and who had stored Bellairs’s specimens from overseas. They published a paper together. Boyd took Bellairs back to Cambridge with him in 1951 but Bellairs preferred London and faced with a heavy teaching load in human anatomy he moved to St Mary’s Hospital medical school in 1953. Many anatomy departments had interests in comparative anatomy and Bellairs became the torchbearer for academic herpetology in Britain, albeit with an emphasis on anatomy, since he was self-avowedly ignorant of the advances in physiology, behaviour and ecology.

Joining Bellairs as co-editor of Smith’s book and then the sole author of the follow-up volume in the same series, Reptiles and Amphibians in Britain, Deryk Frazer had a somewhat similar history but this time came from medicine to become a professional working in conservation via physiology. John Francis Deryk Frazer (1916-2008) was born of a professor of anatomy at St Mary’s, John Ernest Sullivan Frazer (1870-1946). Switching from maths to physiology at Oxford he qualified in medicine in 1942. For the rest of the war he served as a surgeon in the Royal Navy on the new frigate HMS Helford in the Indian and Pacific Oceans. He then became Assistant Lecturer in Physiology at St Mary’s, a famous department headed by Arthur St George Joseph McCarthy Huggett FRS (1897-1968) engaged in fetal physiology and growth. Frazer worked on factors affecting fertility in the rat which formed the basis of his London PhD thesis awarded in 1953 (a mistake in a biography mistakenly attributed his PhD to work on toad movements). From St Mary’s he moved to the department of physiology at Charing Cross Hospital medical school where his main work was again on fetal growth and survival in collaboration with Huggett. However in 1959 he ditched academia to join the Nature Conservancy where he was a member of the British delegation at the first CITES convention. He did, however, continue his interests in fetal growth, publishing a paper in 1970 with the then late Professor Huggett. He continued his early interest in amphibians and reptiles into retirement particularly in Kent.

I knew both Bellairs and Frazer but only when writing this did I realise that Frazer was the older man.

Smith and Frazer from Contributions to the History of Herpetology (see below); Bellairs from Herpetological Journal


It was not unusual, of course, for those in medical practice to indulge in biological hobbies but the involvement of the the three authors was something on a much greater scale. Britain’s medical schools, which I have to explain were and are very different from those, say, in the U.S.A., produced many qualified doctors who did not want to become doctors in the first place but persisted under parental pressure, were attracted to biological research but who finished their clinical studies in order to gain a qualification, or who simply found they did not like medical practice once they had qualified. Direct entry into the biological sciences was often difficult especially for boys since biology was not taught at all in what were considered the good schools.

An example from our time as students in the 1960s was the famous insect physiologist, Sir Vincent Wigglesworth FRS (1899-1994). All his spare time as a medical student was spent studying insects. Medical graduates turning to zoology were always described as ‘having seen the light’.

Biographies of all three are in the three volumes of Contributions to the History of Herpetology,  edited by Kraig Adler, Society for the Study of Reptiles and Amphibians.

Frazer D. 1983. Reptiles and Amphibians in Britain. London: Collins

Smith M. 1951. The British Amphibians and Reptiles. London: Collins

Thursday 12 November 2020

The critically endangered Tamaraw: more bad news

I have written previously (here) about the Tamaraw (Bubalus mindorensis), the small buffalo found only on the island of Mindoro in the Philippines and of how I had seen one in Manila Zoo in 1967. When I wrote that article I had found that an attempt to create a captive-breeding group of this critically endangered species had failed. Yesterday I read in the latest edition of Keeper Contact (165, November 2020) that the last animal in that group had died:

Here is my old photograph taken in January 1967:

Tuesday 3 November 2020

Fluorescent Platypus: any biological significance?

An interesting observation of fluorescence in ultraviolet (UV) light has been reported in museum specimens of the Platypus (Ornithorhynchus anatinus); the fur shone green-cyan. The Platypus has thus joined a handful of other mammals in displaying this phenomenon.

The functional significance, if any, remains unknown. The authors come up with a suggestion that absorption of UV (with emittance of light of longer wavelengths) might reduce the animal’s visibility to predators equipped with an ability to see UV. How this might work in a crepuscular or nocturnal animal I do not know. Or it could it could increase visibility of one platypus to another platypus by shifting invisible UV radiation to the visible range as darkness falls. Or it could have no biological significance whatsoever, being merely a physical property of the fur that has not been selected against; an epiphenomeon, in other words.

An example I quote when talking about animal coloration is that biochemical pathways that produce coloured compounds may be selected against in animals that live in daylight. By contrast in the lightless depths of the ocean or in caves an animal can be any colour. It just does not matter. If a biochemical pathway advantageous to, say, conserving energy, were to produce a colourful compound as an intermediate, it would be of no consequence. Similarly, blind cave fish or salamanders are often white. Why waste energy producing pigment when nothing can see them?

As I was writing this Jerry Coyne has also commented on this paper here. He also raises the possibility that it is a biological epiphenomenon.

This is clearly a phenomenon to investigate even if it turns out to be biologically unimportant. I can already envisage a few Australians out in the bush shining a UV lamp at platypuses in the water. If I were there I would be. I like watching them anyway, having been lucky enough to see them wherever we went looking for them in Queensland and Tasmania.

I must also tell my physicist friends. Just what is it in the fur of these few species that is acting as fluorophore?

Anich PS, Anthony S, Carlson M, Gunnelson A, Kohler AM, Martin JG, Olson ER. 2020. Biofluorescence in the platypus (Ornithorhynchus anatinus). Mammalia published online October 15, 2020 

Beale’s Terrapin or Turtle: An Endangered Species in Hong Kong

The freshwater chelonians, terrapins in English usage and turtles in American, of China and south-east Asia generally are in big trouble. Extensive trade for the human food and ‘medicine’ markets, the pet market, as well as loss of habitat have brought many to the status of ‘Endangered’.

As a result of reading a paper on one of the species in Vietnam I found a video taken recently in Hong Kong of Beale’s Terrapin, Sacalia bealei, where they are very rare and strictly protected. They are nocturnal, occurring in and around mountain streams. The location of sightings is being kept secret because it is thought poaching may still be going on.

Beale’s Terrapin was first described and named by John Edward Gray at the British Museum in 1831. Of the members of the Beale family who worked in India and China, the most likely candidate for the eponym is Thomas Beale (ca 1775-1841) a wealthy merchant in Macau who kept a large collection of exotic birds, including a bird-of-paradise, at his mansion. He with his partners in Magniac & Co (which morphed into the mighty hong, Jardine, Matheson & Co) dealt in opium, cotton and tea. For a time he was immensely wealthy but after dealing in opium futures and investing in some dodgy businesses in Brazil he ended up owing the East India Company the equivalent of many millions of pounds. His body was found washed ashore several weeks after he disappeared from his house.

John Reeves (1774-1856) sent the specimens back to London. He  was working largely in Macau as Inspector of Tea for the East India Company. Gray named Reeves’s Terrapin, Chinemy reevesi, after him, also in the 1831 publication.

The species is sometimes called Beale’s Four-eyed Terrapin because of the eye-like spots on the top of the head. However, since another currently-recognised species from further south in China, Laos and Vietnam, Sacalia quadriocellata, is usually known as the Four-eyed Terrapin, it seems better just to use Beale’s for the species from further north. Just to confuse matters, the two were often considered the same species with the Four-eyed as Sacalia (originally Clemmys) bealei quadriocellata). Both forms have four ‘eye’ spots. Mitochondrial DNA analysis suggests two species but I am not wholly convinced they constitute more than one’ biological species’.

It was not until 1977 that one was found in the wild in Hong Kong, or at least recognised as such, a point I will come back to later.

My mind was taken back to late 1966 or early 1967 when a lecturer in biology at Hong Kong Baptist College brought some terrapins she had bought in a market in Kowloon over on the Star Ferry to HKU. She left them for me to have a good look at. After I returned them she was going to release them somewhere in the New Territories. I know she was keeping a regular eye on the terrapins appearing in the markets and I suspect she rescued more. Unfortunately and infuriatingly, I cannot remember her name and our correspondence has also been lost.

The most interesting species she had acquired were Beale’s Terrapin which we could see seemed to occur in two colour forms. I see that this variation is now ascribed to a difference between the sexes. The male is what was called the ‘pink’ form, with dark brown or black with dark spots and squiggles especially on the leading edge. The neck has pink stripes and the iris of the eye is also pink. The female is the ‘yellow’ form; the carapace is yellowish-brown; the stripes on the neck are yellow, as is the iris.

We photographed the individuals on the roof of the later-demolished Northcote Science Building. Unfortunately I used Agfacolor CT18 film which deteriorates markedly with age. However, I have three photographs which are worth showing here. The ocelli or eye spots can be seen in what is obviously a female—a feisty female. She shot her neck out to bite the rubber gloves my wife had in her hand and was about to put on since she was trying to keep her hands dry while terrapin wrangling. The rubber gloves make an accidental appearance in several photographs at that time since her (wife, not terrapin) hands were suffering the effects of exposure to the histologist’s favourite solvent, xylol (xylene). The ones I photographed were around 13 cm or 5”, not far off the maximum length of about 18 cm.

Beale's Terrapin - male

Same individual as above

Beale's Terrapin - female
Note the 'eye' spots on top of the head

It was impossible to find out if the ones that appeared in the Kowloon market (we never saw this species in Hong Kong Central Market which we kept an eye on if in town) had been caught in Kong Kong or had been brought in from China. Since they had not then been found in the wild in Hong Kong we assumed they had been brought over the border.

More information and modern photographs can be found here.

This is the video I found:

While it is true that the number of people looking for reptiles in Hong Kong increased markedly in the 1970s, with many more species, especially snakes, being found, I cannot help wondering how many Beale’s Terrapins my friend bought in the market and then released. And did others do the same? So is it just within the bounds of possibility that at least some of the Beale’s Terrapins living in Hong Kong are descended from those released individuals? Could there have been an unrecorded but successful re-introduction?

Beolens B, Watkins M, Grayson M. 2011. The Eponym Dictionary of Reptiles. Baltimore: Johns Hopkins

Karsen SJ, Lau M W-N, Bogadek A. 1998. Hong Kong Amphibians and Reptiles. Second Edition. Hong Kong: Provisional Urban Council

Le MD, McCormack TEM, Hoang HV, Duong HT, Nguyen TQ, Ziegler T, Nguyen HD, Ngo HT. 2020. Threats from wildlife trade: The importance of genetic data in safeguarding the endangered Four-eyed Turtle (Sacalia quadriocellata). Nature Conservation 41, 91-111.