Related Clues:

• Volatile liquid
• Upper regions of space
• It can knock people out
• Old operating room substance
• A number of people?
• Potent anesthetic
• Numbing agent
• Volatile solvent
• Anesthetic
• Outdated anesthetic
• It can knock you out
• Old sleep-inducer
• Number no longer used
• Outer space
• Flammable solvent