Chemistry of the wonders

A few physical phenomena believed to be religious miracles are considered, and scientific explanations for them are proposed. The liquefying blood of St Januarius (in Naples) possibly consists of a thy xotropic substance, changing its state from gel to sol when handled during the ceremony. An exact reproduction of it was obtained using materials and techniques available in the Middle Age. The liquefying blood of St Lorenzo (Frosinone) was actually examined and tu rned out to be a substance melting at 29 degrees C, during the hot South-It alian summer. The plausibility of weeping icons is very low if the kind of scientific tes ts and controls performed on them are taken into account. A mysteriously we eping statue was made as a lab curiosity to show how easily similar phenome na can be reproduced. "Blood" on Holy Hosts (Miracle of Bolsena and other) was in 1821 demonstrat ed to be a bacterial contamination from Serratia marcescens, a bacterium pr oducing a red pigment, and this phenomenon, too, can be easily reproduced.