Kills germs on contact so you can take it to purify water of not large matter but bacteria are dead when you swish it around. European blue bloods used it to keep them healthy and I think it was used during the black plague to make sure they didn't die. The blue blood was a condition called Argyria from ingesting silver made your skin pale and your veins show very blue. We've all heard born with a silver spoon, that was used to eat with to make sure food was not going to make them sick because there was no refrigeration. I think the paleness was also because they likely were cautious about going outside for fear of being killed by an enemy in wait. They should go out anyways because the sun is natures vitamin that keeps you healthy and not depressed so your mood would be helped by just going out for a bit.