the cairo toe

the bbc reports about a prosthetic toe:

"An artificial big toe found on the foot of an ancient Egyptian mummy could be the world's earliest functional fake body part, UK experts believe. A Manchester University team hope to prove that the leather and wood "Cairo toe" not only looked the part but also helped its owner walk. They will test a replica in volunteers whose right big toe is missing. If true, the toe will predate the currently considered earliest practical prosthesis - a fake leg from 300BC. The toe dates from between 1069 and 664BC, so if we can prove it was functional then we will have pushed back prosthetic medicine by as much as 700 years."

i wonder how they find the volunteers?