'I have eaten many curious things in my life but never before a king's heart.'

An x-ray of Queen Marie of Romania's right hand will be auctioned this week by the Romanian auction house Artmark .

Which reminds me of something. 

Which king's heart was preserved as a valuable conversation piece until some doctor in the 18th century, who was shown it, proceeded to swallow it, saying, 'I have eaten many curious things in my life but never before a king's heart'? 

I read it in a 19th century collection of anecdotes, hidden among very many dull stories, but I cannot remember who the king was or the doctor l nor find it on the net.

If I had read systematically instead of at random how much I should now know.

Later note.

I found it! Though it was a 19th century clergyman not an 18th century doctor. It was the Very Rev. Dr. William Buckland (12 March 1784 – 14 August 1856) who was Dean of Westminster and of whom Wikipedia tells that:

His passion for scientific observation and experiment extended to his home life. Not only was his house filled with specimens – animal as well as mineral, live as well as dead – but he claimed to have eaten his way through the animal kingdom: zoophagy. The most distasteful items were mole and bluebottle; panther, crocodile and mouse were among the other dishes noted by guests. Augustus Hare, a famous English raconteur and contemporary, recalled, “Talk of strange relics led to mention of the heart of a French King preserved at Nuneham in a silver casket. Dr. Buckland, whilst looking at it, exclaimed, ‘I have eaten many strange things, but have never eaten the heart of a king before,’ and, before anyone could hinder him, he had gobbled it up, and the precious relic was lost for ever.” The heart in question is said to have been that of Louis XIV. Buckland was followed in this bizarre hobby by his son Frank.