The Case of the Missing Earring

I lost one of my very favorite earrings yesterday.   I was walking Nigel and the earring must have slipped off my ear.   I discovered it was gone as soon as we got home.  It's not the end of the world, but I did think -- that given that we walked only two blocks -- Nigel should be able to track the lost earring.  After all, Steven Reinberg's Health Day article Trained Labrador Can Sniff Out Colon Cancer,   http://consumer.healthday.com/Article.asp?AID=649419 details how "specially trained 8-year-old female Labrador retriever named Marine is able to detect colorectal cancer among patients with up to 98 percent accuracy."   I showed Nigel the remaining earring.  I put it right under his nose, and then we retraced our steps -- twice.  No earring.  He stopped several times spending a little extra time sniffing leaves and tires, but the green and orange glass earring was never located.