Gurney's other main body of work is closer to ordinary psychology and is the part most likely to be read with profit today. He ran long series of experiments on hypnotic suggestion, including tests of whether a suggestion given under hypnosis could take effect later without the subject recalling that it had been given, and whether a hypnotised subject could respond to instructions the hypnotist had not spoken aloud. The first line of work belongs to the mainstream history of research on suggestion and post-hypnotic response. The second was intended as a test of telepathy under conditions Gurney thought controlled, and it was subsequently argued that his hired subjects had opportunities to communicate that he had not eliminated.
Gurney died in a Brighton hotel in June 1888 from an overdose of chloroform, which he had been using for neuralgia. The inquest returned accidental death. Suggestions of suicide, sometimes connected to doubts he was said to have developed about the reliability of those very subjects, have circulated since and have never been substantiated. He was forty-one, and the society lost the only person doing its detailed work full time. His work on suggestion was picked up by later experimental psychology in a way none of his case collection ever was.