A laboratory stain. Also known as 1,2,3-triketohydrindene, it fluoresces purple when exposed to amines. This would be uninteresting if not for the fact that people are amines. Get some ninhydrin on your skin and you'll be purple for a while. You WILL get some on your skin. You can try hard not to, but you'll notice unwashable purple spots on your hand, face, arm, and wherever else it decides it would be fun to appear on. If you touch your face, you will have purple spots you cannot wash off with it. If you put the ninhydrin solution into a squirt gun, you can turn your friends purple. Fun for the whole family!
Rufus noticed his hand was covered in purple spots. Rather than leprosy, he expected ninhydrin.
by Basketball Jesus June 20, 2005