The Doctor is the final of the characters whom Marlow meets in Europe. He seems to take little interest in Marlow’s physical health – only briefly and absent-mindedly taking his pulse – but shows much interest in his psychological health. The Doctor asks whether he can measure Marlow’s head, a reference to phrenology, a pseudo-science popular in the early 19th century. He also inquires as to whether there is any madness in Marlow’s family. The implications are clear – quite simply, the Doctor believes that Marlow’s journey will cause him to “go mad”. This portentous incident is one of the many that foreshadows Marlow’s meeting with Kurtz (though as Marlow later notes, Kurtz is not exactly “mad”). Later, Marlow remembers the Doctor’s words, and suggests wryly that he feels he is “becoming scientifically interesting”.
