To the person in the bell jar, blank and stopped as a dead baby, the world itself is the bad dream.
Amongst the horrendous "medical" procedures for mental patients during the time of Sylvia Plath, why does she choose the unsuspecting bell jar as a major symbol and even title for her novel? A bell jar is a inverted glass jar used to contain and preserve specimens in the vacuum created by its bell-like shape. Sylvia Plath's protagonist, Esther Greenwood, feels trapped beneath a bell jar as she is tormented by her depression. While transferring to a new mental hospital, she says, "Wherever I sat—on the deck of a ship or at a street café in Paris or Bangkok—I would be sitting under the same glass bell jar, stewing in my own sour air" (Plath 185). This metaphor shows Esther's isolation from normal society and introduces the bell jar as a symbol for confinement.
Esther's confinement is both metaphorical and literal. She is metaphorically trapped in the "sour air" of the bell jar, but she is also physically confined and isolated in mental hospitals during her depression treatment. However, this was the societal norm at the time. Esther's mental hospital, Buddy's tuberculosis sanatorium, and the Deer Island prison Esther sees on a walk are all places of isolation for those deemed unfit by society. This supports the notion that while Esther's depression has created the fictitious bell jar for her, society has enforced the isolation and confinement even further.
Even after her recovery, Esther will always be terrorized by her depression and will always be aware of the omniscient bell jar hanging over her. She remarks, "How did I know that someday—at college, in Europe, somewhere, anywhere—the bell jar, with its stifling distortions, wouldn’t descend again?" (Plath 241). Not only does this quote show Esther's mental anguish, but also compromises her reliability as a narrator when she refers to the "stifling distortions" that have clouded her mind throughout the entire novel. Readers can feel these distortions in her narrative, which switches between times and events and is at times confusing.