Water 2

Among the earliest Greek philosophers—now commonly known as the pre-Socratic philosophers—stands Thales of Miletus* (c. 626/623–c. 548/545 BC). Living around 150 years before Socrates, he is often considered not only among the first chronologically but also among the foremost for the quality of his thought. Among his work in geometry, he is remembered eponymously in Thale’s theorem. However, it is not necessarily for the scientific accuracy of his thought that he is still held with some regard. It is also for his attempts at trying to make sense of the world; attempts that missed the mark. For example, Thales thought that the Earth floated on water.

Of interest here is that he held water to be the first principle—or arche—of everything. That is, everything in nature was based on a single elementary substance, which Thales proposed was water. Although it may seem odd to us today, in the ancient world this view became widely influential.

Socrates took a different approach. He questioned how we could be sure about our views. He famously refused to speculate about such matters. Such a proposal as Thales’ would not have fit well with him. However, how much of a speculation is it to suggest that water is the ‘first principle’?

Apart from the scientific basis of water for life (see an earlier post) water has a special place in human experience. This is because of its physiological importance.

Viewed in terms of physics, water is a molecule: one of the most widely known. Many who do not know what ‘H2O’ means in the scientific sense have heard of it and are aware that it relates (in some way) to water.

Water is made of elements—hydrogen and oxygen; it is a molecule and not itself an element. But as a molecule, water does have a fundamental position with respect to life. Indeed, the search for extraterrestrial life typically goes hand in hand with the question of liquid water being present. That is, not just ‘H2O,’ which may be in the form of ice or vapour, but ‘liquid H2O.’

Water provides a physical medium within which the processes that gave rise to life can take place. That is where the processes that characterise life first occurred and now continue to take place. All organisms, whether they are plants or animals, are water-based. No living thing is devoid of water. To be devoid of water is to be lifeless—even dead.

An interesting creature is the tardigrade. This tiny creature can resist considerable environmental extremes—including exposure to outer space—without dying. They can take on an inactive state when put to extremes and return to life afterwards when returned to a normal environment. One extreme that they can withstand is desiccation.

However, as I understand it, liquid water may be lost, resulting in the tardigrade taking on an inactive form called a ‘tun.’ However, despite desiccation, some water molecules remain within the substance of the quiescent tun. This is because of the presence of the sugar trehalose. Indeed, other organisms that can also withstand desiccation also have this mechanism. While this is not the only mechanism available to the tardigrade—for example, it is able to modify certain structural proteins in response to desiccation—water nevertheless has a fundamental place in its continued existence—even when inanimate.

I am not aware of any of the existentialist philosophers ever giving water much attention in human existence. In Being and Nothingness, Sartre briefly discusses the experience of being-in-the-world in relation to the element of water, but this is not a major part of his philosophy. Camus, in The Myth of Sisyphus, uses the image of a river to represent the absurdity of human existence, but again, this is a passing reference rather than a central theme.

Only the philosopher Gaston Bachelard wrote about the symbolism of water in his book Water and Dreams. He explored how water is often associated with purity, life, and the unconscious. However, Bachelard was more of a phenomenologist than an existentialist, and his focus was on the imaginative experience of water rather than its existential significance.

* Mietus was a Greek colony in Ionia on the western coast of Asia Minor and so not in the territory that forms modern-day Greece.

Circulation Figures (Human)

Here—after my digression (posted 5 minutes ago) about AI-generated images of the human circulation—are some images from a book first published in 1964. Both come from ‘Principles of Pathology’ written and illustrated by Howard Carl Hopps. This is the only book I can think of that has two quite different illustrations for the same thing. This reflects the different contexts and ways in which Hopps is referring to the circulation in the text. This is a practice that might be more widely adopted. The structure and workings of the human body can be envisaged in numerous different ways at the same time. Diagrams and figures should be allowed to express this.

Again we see how the same system can be depicted differently by different illustrators/authors.

Circulation Figures (AI)

This is an extra post prior to posting another in my series of diagrams of the human circulation. This is to warn you about the potential dangers of AI-generated images. 

Just to see what I might get, I asked an AI image generator to make an image of the human circulation. This was a generator that had produced nice pictures before, but I had not asked for figures or illustrations. I had hoped to post what I was given. To say that the results were dreadful is an understatement.

While there was some anatomical similarity with the human body, there were subtle inaccuracies and false impressions. AI-generated images must be carefully checked before they are used or relied upon.

I recently heard that two things that AI cannot do are produce an image of a person writing with their left hand and an image of an analogue clock face showing a specific time. Drawing from what is on the internet, AI predominantly finds images of people writing with their right hand and clock faces registering ten-to-two (a standard in advertising). So AI has known limitations, which I’m sure will be overcome.

In my requests, what was particularly bad was the labelling; it was complete gibberish. It consisted of very strange combinations of letters and partial letters. Drawn from the internet, the labels of the images used do not seem to be read as text but taken as part of the image. Connecting the right labels—where there were readable labels—to the appropriate structures was non-existent.

This may only be a temporary thing. This time next year perhaps I should try again. For the purpose of providing figures and illustrations, AI still has a lot of developing to do. In the meantime, students and teachers should be cautious.

Eponyms 1

One of the things for which anatomy used to be famous was its eponyms. An eponym may be a person, place, or thing from which something takes its name. Perhaps the most famous but overlooked eponym is the sandwich. Although there is disagreement over how the eponym came about, all agree that it was named after John Montagu, the 4th Earl of Sandwich.

Most anatomical eponyms are named after people. But there have been a lot of people doing a lot of work on the same things. Some structures have been named more than once. Some have merely identified a structure; others have come after and done detailed work on its structure and function. After whom should such a structure be named?

Eponyms are particularly problematic in that they usually contain no indication of where in the body they are located and may lack anything to indicate to what they might refer. This is an obvious problem for the student—or at least, it was. Fortunately, the use of eponyms has been discouraged. Beginning in 1895 with the Nomina Anatomica, the aim has been for a standard nomenclature for anatomical structures. This was superseded in 1998 by the Terminologia Anatomica.

Unfortunately (for some), the nomenclature used is often based on Latin. Without a basic knowledge of Latin, one may have difficulty remembering the terminology.

That said, a ligament I found very easy to remember when first learning anatomy was Poupart’s ligament. From its name, one could at least surmise that it is a ligament of sorts. It is a fibrous band in the groin. It is now called the inguinal ligament, which provides an adequate description of where and what it is.

The eponym is rather distinctive It has nothing to do with the smell (poo!) of the parts near to which it is situated (or so I used to, light-heartedly, tell my students). Although that was a perfect way of remembering where it was. I did not know it at the time (and I don’t think my teacher ever knew) that it was named after the French physician, anatomist and entomologist François Poupart (1661-1709).

As noted above, a common problem with eponyms is that they are sometimes named after more than one person. That is the case with Poupart’s ligament. It is sometimes referred to as the Fallopian ligament, after Gabriele Falloppio (1522/23-1562), who is most famous for another eponymous structure, the fallopian (now uterine) tubes.*

It was Falloppio who first described the inguinal ligament. It was Poupart who highlighted its clinical relevance in relation to inguinal hernia. Based on that, who merits the eponym? (The simple answer is, ‘Neither; eponyms are no longer used!’)

Furthermore, Poupart’s ligament is sometimes confused with Colles ligament after Abraham Colles (1773-1843)—perhaps most famous for Colles fracture—a common form of wrist fracture. Colles ligament is also in the groin but is correctly the ‘ligamentum inguinale reflexum—triangular fascia’ or nowadays ‘reflected inguinal ligament (triangular fascia).

*(Surprisingly, the fallopian tubes still go by the eponym on Wikipedia, where the following note is given…

“Though the name Fallopian tube is eponymous, it is often spelt with a lower case f from the assumption that the adjective fallopian has been absorbed into modern English as the de facto name for the structure.”)

William Harvey’s Dissected Family

Having commented about how the Achilles tendon came to be named following the dissection by Philip Verheyen (1648-1710) of his own amputated leg, I came across a note I copied from an unknown source about William Harvey (1578-1657), the discoverer of the circulation of the blood. It reads…

'Harvey's quest for knowledge and lack of human material led him to dissect his own sister and father when they died. Surprisingly, Harvey did not like the idea of having his own body dissected after his death and requested his corpse be wrapped in lead to protect it from other anatomists'.

Upon checking this, I have found that there is a story in circulation (pun intended) about Harvey having dissected his own father and sister—or at least having witnessed their dissections. However, there also appears to be no historical evidence that this was ever, in fact, the case. Beware.

Eric Laithwaite and the Lesson of the Gyroscope

Somebody who frequently appeared on television when I was a boy was the electrical engineer Professor Eric Laithwaite (1921-1997). This was in the late 1960s and early 1970s. This was in the era before the emergence of today's more ‘telegenic’ popularisers of science. I don't think anybody would have described Laithwaite as 'telegenic;' he seemed to be a rather gruff, although not unfriendly, character with a strong Lancashire accent. He and those scientists with whom he often appeared had a much greater sense of gravitas about them than current science presenters, and yet they were still able to appeal to a young audience. Indeed, he twice gave the Royal Institution Christmas Lectures in 1966 and 1974.

One of Laithwaite's interests—highlighted in his 1974 lecture—was the properties of gyroscopes. This seems to have been sparked by his meeting with an amateur inventor called Alex Jones. Laithwaite's pronouncements on gyroscopes were controversial at the time—and probably still are. This is because what Jones had built, based around a gyroscope, seemed to contradict certain laws of physics—not least Newton's Third Law of Motion (the one about there being to every action an equal and opposite reaction).

Be that as it may. Something I took from hearing about this was from what happened next. In order to find out how he had been able to build such a machine, Jones took it to pieces. Then, upon reassembly, he found that it did not behave in the way originally observed! (At least, this is how I understand the story; I only remember these few details.)

If there is a moral to this story, it is about the dangers of reductionism. As a whole, Jones's machine behaved in a certain way—or at least seemed to. To try to understand this machine as a whole, what would have been the best approach? As it turned out, taking it to pieces was certainly not the ideal. Indeed, was it even necessary to disassemble it? The machine had been built from a known set of parts put together according to certain plans. Were there not also other recollections about its construction that would have made the assembly of a replica possible? Why take apart when one could make an exact copy? Then, should both machines behave in the same way, one’s initial findings would be on an even firmer foundation.

Here, I am interested in the human body. How might we understand it better without taking it apart? What lessons might we draw from the story of Jones and Laithwaite?

Achilles’ tendon

Although referring to a well-known character from the Trojan War of the 12th or 13th century BC, the thick tendon behind the ankle only came to be known as the Achilles’ tendon after the late 17th century. The oldest-known written record of the tendon bearing the name is from 1693 by the Flemish/Dutch anatomist Philip Verheyen (1648-1710). In his widely used anatomical work, Corporis Humani Anatomia he described the tendon's location and said that it was commonly called 'the cord of Achilles'.

The tendon had been described as early as the time of Hippocrates, who described it as the 'tendo magnus' (Latin for 'great tendon'), although there is some debate about this. From what I can ascertain, Hippocrates did not call the Achilles tendon the 'tendo magnus'. He referred to it instead as the 'neura megala', which translates as 'great tendon'. The term 'tendo magnus' was used by later anatomists prior to Verheyen. Another associated term was 'chorda Hippocratis' (Latin for 'Hippocrates' string').

In using the term Achilles’ tendon, Verheyen is referring to the mythological account of Achilles being dipped into the River Styx by his mother Thetis while being held by his heel. Where the water wetted him, his body was rendered invulnerable. As the heel by which his mother held him was not touched by the water, it was his one vulnerable spot (hence the association of the phrase 'Achilles' heel' with having a specific vulnerability). Achilles was eventually killed by a poison dart, which struck him in the heel. 

What is particularly interesting about Verheyen’s naming of this tendon is that he is reputed to have done so having dissected his own amputated leg. There is even a painting of him doing so (below).That leg was not deliberately amputated for purposes of dissection, of course, but the exact reason for its loss I have been unable to find out. Similarly, I have been unable to find out who painted the painting. One source describes it as “Anonymous. From the collection of Pieter Deheijde.”

There is also a suggestion that Verheyen lost his leg fairly early in life. If so, that makes this painting look somewhat anachronistic and calls into question this fascinating story.