Markets in Everything: Cancer Sniffing Dogs

The Economist recently had a story of how doctors have smelled patients breath as a way to test for sickness. It's inprecise and can't detect everything, so Carolyn Willis outsourced the smelling of sickness to dogs.

One of the first practitioners of the field of olfactory diagnosis, Carolyn Willis of Amersham Hospital in Britain, decided to contract the job out to dogs. They, she reckoned, have the necessary nasal apparatus to sniff out illness, and there was already some anecdotal evidence that they could, indeed, smell people with cancer. It worked. For the past four years her sniffer dogs have been diagnosing bladder cancer. She is now training them to detect prostate cancer and skin cancer as well.