What was Barbet skeptical about, and how did he test his skepticism?

Skeptical that a nail through the palm would be capable of supporting half the weight of an adult male, Barbet tested the theory by nailing up a newly amputated arm attached to a 100-pound weight. As suspected, the weight was too much. Barbet went through a dozen amputated arms, finally deciding "as though through divine intervention" that the nail went through part of the wrist called "Destot's space." Barbet then claimed that the location exactly matched the location of the wound in the Shroud of Turin.