Kaare Lund Rasmussen and co-researchers from the University of Southern Denmark in Odense, The Institute of Anthropology, Archaeology and Linguistics in Hojbjerg, and the Christian-Albrechts University in Kiel studied bones that had been interred in Danish cemeteries. Two Franciscan friaries, a Cistercian abbey and a parish churchyard at various locations were examined.
Leprosy and syphilis were each identified by the type of bone lesions observed and a third condition, known as focal osteolytic syndrome that was identified as recently as 1996, was also detected in some of the skeletons. Individual specimens from 12 individuals were radiocarbon dated by gas proportional counting and the more sensitive technique of accelerator mass spectrometry. The ages were adjusted to allow for the effects of diet.
They found a relationship between certain type of bone lesions -- indicating certain diseases like syphilis and leorpsy -- and higher amounts of mercury. Today we go bonkers when someone breaks a fluorescent bulb but it was routinely used to treat disease.