科学美国人60秒:化学家调查卡萨诺瓦的淋病

This is Scientific American — 60-Second Science. I'm Karen Hopkin.
Casanova. The name is synonymous with a reputation for romantic—let's say excess. But a new study suggests that the real Giacomo Casanova may have exaggerated his sexual exploits—not in terms of their sheer volume, but in their infectious aftermath. Because though Casanova claimed to have suffered several bouts of gonorrhea, researchers could find no trace of the responsible microbe on the pages of the womanizer's handwritten memoir. The findings will appear in the journal Electrophoresis.
Casanova's memoir, completed in 1798, fills 12 volumes, and its English translation runs to 3,500 pages. In this tell-all, Casanova tallies some 122 lovers and confesses to recurring gonorrheal relapses.
To investigate these claims, researchers turned to a technique they had previously used to positively identify the bacterium that causes plague on the pages of death registries from 17th century Milan.
"Thus we thought we would be able to detect the gonococcus on Casanova's pages, since he candidly admitted, in his memoirs, having been infected by gonorrhea in his first sex intercourse at the age of 18 and having suffered from relapses of this sex pathology along his lifetime as a gallant lover."
Pier Giorgio Righetti, professor emeritus at Milan Polytechnic.

Righetti and his colleague Gleb Zilberstein, who heads a company called Spectrophon in Israel, developed a handheld device that allows them to capture and characterize protein fragments and other macromolecules from the surface of historical documents. Such biological materials can get stuck to a manuscript when, say, someone licks his fingers to more easily turn the book's pages, leaving behind traces of potentially infected saliva.
But in the case of Casanova, "as luck goes, no traces of gonococcus could be detected."
They did, however, find traces of cinnabar, a red pigment containing mercury sulfide. At the time, that chemical was used to treat the sexually transmitted diseases du jour, including syphilis and gonorrhea.
"It is thus quite likely that Casanova had been using mercury sulfide to cure a relapse of his pathology."
So it could be that his infection was in remission when Casanova penned the three or four pages of Chapters 1 and 2 that the researchers were able to examine—and that in addition to his way with women, Casanova also had a deft hand with 18th century pharmaceuticals.
Thanks for listening for Scientific American — 60-Second Science. I'm Karen Hopkin.