Here's a fact you need to know: if you cut your hand on someone's tooth, it's the same as cutting it on the edge of a sewer.

I learned this little-known fact from watching yet another forensic science show. These shows manage to scare the crap out of me in new ways every day. And yet, I don't know, I'm addicted to them.

Anyway, this particular show was about a guy who broke into a woman's apartment, punched her in the face, killed her and ran away. He was forced to go to the hospital a few hours later because his hand had turned a horrifying shade of purple and swelled to the size of a football. The doctor recognized the wound as a "fight bite" though the killer claimed he had cut himself on the edge of a dumpster.

"From the infection, I knew he could have only cut himself on a human tooth. The human mouth contains so many different kinds of bacteria that it's pretty much like cutting yourself on the edge of a sewer."

And with those words, the good doctor changed my perspective on french kissing forever.

Oh, and also on punching people in the face.