A folk tradition in Denmark and southern England imaginedĀ sea urchin fossilsĀ to be thunderbolts, able to ward off harm by lightning or by witchcraft, as anĀ apotropaic symbol.Ā Another version supposed they were petrified eggs of snakes, able to protect against heart and liver disease, poisons, an

Zinc was identified to be essential in fungal growth of yeast as shown by Jules Raulin in 1869 yet no proof for the need of zinc in human cells was shown until the late 1930s where its presence was demonstrated in carbonic anhydrase and the 1960s where it was ident