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Thursday, 21 February 2013



In the past, a large part of medical training involved learning the names of things, and how to recognise them.

Most of these were named in Latin, and so it was necessary for medical students to have at least a small amount of Latin, though it is probably open to question whether they ever gained from this knowledge, save for the odd occasion when they bumped into a foreign anatomist, and felt driven to discuss the fine points of a bone they were gnawing. Still, the habit took hold, and lasted.

This is why zoologists, palaeontologists, and others working with bits of anatomy also needed, and still need, to know this rough Latin, which is how I came to be reading about the vinegar pot of a dinosaur. Actually, it was a paper about the cursoriality of dinosaurs, their running behaviour, and nothing to do with the cursor, but the authors were drawing some interesting inferences on the location of the acetabulum in the pelvises of some dinosaurs, but this object is no more than the socket of the hip joint.

The original acetabulum was a vinegar pot, placed on the table in ancient Rome, and from there it became a measure, half a gill, in fact and then, perhaps for its size and shape, the socket that the hind leg goes into. The vinegar itself is a dilute solution of acetic acid, which the chemists now call ethanoic acid, but the Romans called their sour wine 'acetum', and that name has lived on in many chemical names that we will come to in a moment.

The acetabulum bobs up in a number of forms, apart from the bony version. The name is applied to the suckers on squid, cup-shaped cavities or organs in general, a lobe of the placenta in ruminants, and any socket on any joint of an insect. And in fungi, there are certain cup-shaped receptacles called, guess what? That's right, each of them is an acetabulum.

Now back to acetum, though. Aside from acetic acid, we know the term mainly in the form of acetate, though a particularly pedantic chemist might wish to call the substances that we call 'acetates' by the approved title, 'ethanoates'. To the rest of us, 'acetate' is fine, and it is even a registered name for a fabric made from cellulose, somewhat similar to rayon. Chemically, it is cellulose acetate, and it was once known as acetate rayon.

Acetate can be a bit of a problem when you try to use it: the plastic dissolves in a number of common chemicals such as the solvent used in nail polish, paint remover, and also in a perfume made by Du Pont, called, appropriately, Acete. Sadly, acetate was also used as a plastic to make dolls, and many aging ladies are now finding that their dolls of the 1930s and 1940s are decaying, giving off a vinegar smell as the plastic breaks down again.

All of the metal acetates are soluble in water, except for silver acetate, and lead acetate is known as 'sugar of lead' from its reported sweet taste. Who tested the chemical I cannot say, but there is reason to suspect that the Borgias may have used lead acetate to do away with some of their enemies.

According to the surviving enemies of Pope Alexander VI, the father of Lucrezia Borgia, Alexander himself died when he drank wine from the wrong bottle, which contained his white powder, while attempting to poison a Cardinal Corneto who drank the safe wine.

There are few poisons that can remain unnoticed in wine, but lead acetate would certainly be one of them. Perhaps this is the origin of the old chemists' saying — "he who acetates is lost".

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