In order to treat patients of other species, doctors must download into their brains "Educator tapes" containing the necessary medical knowledge, and these tapes also transmit the personalities of their donors. As a result, doctors have to struggle with the tastes imported from their donors, ranging from a dislike of their own species' normal food to sexual attraction for members of the donor's species. Other running gags include the acerbic tongue of the Chief Psychologist and one very senior non-human doctor's love of gossip, especially about the sexual behavior of other species.