"Or it kills you," Blaise replied cooly.  He knew he'd brewed it right.  The books all said the smell and color were off if you bungled it, assuming it didn't blow up in your face.  He liked watching Greg Goyle lose color, though.  It made the red of his alcoholism stand out more against his pasty cheeks.  He wasn't aging well.  Only in his early twenties and he already looked ten years older.  