"Snow Crash penetrates the walls of brain cells and goes to the nucleus where the DNA is stored. So for purposes of this mission, we developed a detector that would enable us to find cell wall-penetrating compounds in the air. But we didn't count on heaps of empty testosterone vials being scattered all over the place. All steroids—artificial hormones—share the same basic structure, a ring of seventeen atoms that acts like a magic key that allows them to pass through cell walls. That's why steroids are such powerful substances when they are unleashed in the human body. They can go deep inside the cell, into the nucleus, and actually change the way the cell functions.