This isn't something that got passed down like a children's game of "telephone"; the outlandish details are present in the original contemporaneous accounts and we have copies of them (digitized even! [1]). So, if it was made up, it was at least made up at the time.
However, the person making the claim is Pierre-François Percy [2], chief surgeon of Napoleon's Grande Armée and a member of the Académie des sciences and, later, honorary member of the Académie Royale de Médecine. Inventing a case like this would be wildly out of character.
Reflexively dismissing every story from the past is just as fallacious as believing every detail.
However, the person making the claim is Pierre-François Percy [2], chief surgeon of Napoleon's Grande Armée and a member of the Académie des sciences and, later, honorary member of the Académie Royale de Médecine. Inventing a case like this would be wildly out of character.
Reflexively dismissing every story from the past is just as fallacious as believing every detail.
[1] https://books.google.com/books?id=4e0EAAAAQAAJ [2] https://en.wikipedia.org/wiki/Pierre-Fran%C3%A7ois_Percy