After Cambridge he worked on the comparative anatomy of the Himalayan Hispid hare and chemotaxis in leeches, worked in Saudi Arabia studying the immobilization of Goitred and Mountain gazelles, did pupillage at the English Bar, and was a research fellow at the Hebrew University, Jerusalem.
Plague doctors practiced bloodletting and other remedies such as putting frogs or leeches on the buboes to "rebalance the humors" as a normal routine.
The Brain Leeches is a 1977 sci-fi film directed by Fred Olen Ray and starring Paul Jones, Marcia Scott & Ray Starr.