I’ve been rereading the 1979 Thomas Hudson catalogue for the exhibition at Kenwood House. Cat. 66 is extraordinary, the portrait of a young woman, Miss Irons (AH Wright Collection), where Hudson appears to have painted a trompe l’oeil engraving of a doctor over the sitter’s face.

A label on the back of the painting, written when the portrait belonged to the Mudge family in the Nineteenth Century, reads: ‘A picture with scroll over face by Hudson, Sir Joshua Reynolds Master. The original portrait was one of Miss Irons, well-known beauty. When the picture came home she did not think it did her justice & returned it to Hudson to have it improved. He painted over her face the scroll having the portrait of (?)Thomas Mudge saying he would put some sense into her head somehow & that Thomas Mudge was the wisest man he knew.’

As the cataloguer says, ‘the result is almost like a still-life; a remarkable joke which to modern eyes verges on the surreal.’ I haven’t been able to find an image of the original, so you will have to bear with my dramatic reconstruction (with apologies to Christie’s and the National Portrait Gallery).

I like to find examples of Hudson’s sense of humour and Miss Irons’s portrait seemed a good one. The cataloguer said that further technical examination was needed to prove the story, or confirm the attribution. The print had the letters MD below the image. Thomas Mudge was known to be a clockmaker; his brother Dr John Mudge FRS MD (1721 – 1783) did not actually qualify as a doctor until 1781, which is far too late for the apparent date of the engraving. The only clue was the name Fisher on the bottom of the print. The entry ended on a cliffhanger, as the painting was being x-rayed as the catalogue went to print. I contacted Dr Jacob Simon, who curated the exhibition with Dr Ellen G Miles, and asked him what the outcome was. He very kindly sent me a copy of the 1979 press-release.

The mystery was solved, but not in the way that the Mudge family had believed. There was indeed a portrait underneath, and the illusionistic print was of a real doctor, not Dr Mudge but the famous Devon doctor, John Huxham (1692 – 1768). William Schupbach of the Wellcome Institute for the History of Medicine recognised the superimposed print as Edward Fisher’s engraving of Dr Huxham; there is an example in the Wellcome Institute Library.

Dr Huxham was trained at Exeter, Leiden and Rheims and practised at Totnes and Plymouth, where he racked up an impressive score of achievements; as well as being an expert in the study of fevers, he was one of the first to diagnose influenza and scurvy (which as a Devon man he treated with cider) and participated in the first annual log of weather conditions and infectious diseases. He was made a Fellow of the Royal Society in 1739 and awarded the Copley Medal for contributions to medicine in 1755.

(c) The Royal Society

All of this confirms that Dr Huxham was a man of superlative good sense. But, along with the x-ray evidence, it also suggested that the portrait was the work of a different artist. Fisher’s print was engraved after the Royal Society’s portrait of Dr Huxham by Thomas Rennell (1718 – 1788). The story of Miss Irons’s portrait had become garbled by the time the Mudge family recorded it in the Nineteenth Century; the bones of it were true, but the painting had become attributed to a famous artist rather than a forgotten one.

Rennell was a pupil of Thomas Hudson. He was another Devon man, whose work was previously known only from his portrait of Dr Huxham. He was also profoundly eccentric, certainly eccentric enough to have played the bizarre visual joke of painting an engraving over the face of a difficult client. As the press release says:

‘after studying in London he settled at Dartmouth where he lived in great poverty, often remaining idle in bed for a week at a time, eating nothing but cake and water. A chemist, a musician and a poet, he ended his days in an asylum.’

How terribly sad. Ellis Waterhouse in British Eighteenth Century Painters describes Rennell as ‘Devonshire portrait and (bad) landscape painter. Born Chudleigh 1718; died Dartmouth 19 October 1788…. Lived later in Exeter, Plymouth and Dartmouth and was astonishingly idle. He is known only from Fisher’s mezzotint of his John Huxham.’

The Percy Anecdotes, an anatomy of eccentricity, do him more justice:

‘Rennell… was not only an excellent painter, but a good chemist and prepared most of his own colours; a tasteful performer and a fine composer of music; an ingenious mechanic, and no mean poet; but withal excessively indolent. When settled at Plymouth the Duke and Duchess of Kingston were so much struck with some of his paintings, that they endeavoured to draw him from his obscurity by a promise of residence in their house in London, and the exertion of their interest in his favour; but he refused their offer. From Plymouth he went to Portsmouth [Dartmouth] where he lived, or rather existed, for nearly twenty years in great poverty….

‘Although at times Rennell would paint, yet he was generally negligent and improvident; his art had only its turn with his other amusements, and if a picture was completed in twelve months, it was thought very expeditious. Rennell, like many other great geniuses, was an entire stranger to frugality; no sooner was he in possession of a few pounds, but every strange object that presented itself, and was within the compass of his pocket, was bought immediately.

‘The blunt sincerity of Rennell, rendered his manners unpleasing to the rich and powerful, whom he would never flatter, but whose vices and follies were ever the subject of his satire.’

The Percy Anecdotes (1826) by ‘Sholto and Reuben Percy’ (Thomas Byerly and John Clinton Robertson) Volume 10 pp 94 – 95

There in a nutshell is how not to be a society painter.

The Royal Society’s Dr Huxham is a curious work. Dr Huxham must be blind in one eye, but that doesn’t explain the portrait’s lack of engagement; you feel that Rennell sees his sitter as a still-life rather than a living subject. Dr Huxley’s head could lie on its side and be painted like a cabbage with the same effect. Perhaps that’s what happens when you take a year to paint a portrait.

Rennell might never have become a great painter, but he could have been a successful one. Painter, musician, poet, chemist: the ideal accomplishments for a Georgian portraitist. How tragic to have all the gifts but not the alchemy to make them work.

At least Rennell had a sense of humour. The portrait of Miss Irons shows exactly the character given to him in the Percy Anecdotes. It is the cleverest, best -worked example of the Eighteenth Century tradition of settling scores with people by making a practical joke of their portrait: one artist would display the portraits of clients who had not paid their bill in his shop window with prison bars painted over them; the Duchess of Marlborough blacked over the face of one of her daughters’ portraits and wrote underneath ‘She is much blacker within.’

And with Miss Irons the number of known works by Rennell has doubled. Perhaps others will come to light in Devon collections.