Keats, it is well known, had some medical training. He completed his house jobs at Guy's Hospital after becoming one of the first people to pass the licence of the Society of Apothecaries—a GP of the era. His experience of the family tuberculosis that would eventually kill him at the age of 25 and his early years of surgical assistance gave him knowledge and experience of death, the only clue to his medical background that can be seen in his work.

In La Belle Dame Sans Merci, an imitation of a medieval ballad, an alluring, otherworldly damsel has fatally tempted the “knight-at-arms” who …