A story is told that in the 4th century B.C. the soldiers in the army of Alexander the Great werer struck by an outbreak of a mysterious gastrointestinal illness, while they were in foreign lands. It was told that the Greek military commanders did not become ill from the disease as often as their soldiers did, even though they were all living together in the camp eating the same food.
Two thousand years passed by before scientists found an explanation the mysterious disease. The soldiers drank from cups made of tin but the officers had cups made from silver.
It was proved that traces of silver dissolve in water forming a colloid solution where particles of silver actually become a part of the water and this silver solution kills bacteria. So the silver cups of the army commanders were disinfecting the water that was poured into them, while the tin cups did not. So even though the whole camp was drinking the same water it was the cups made of silver that kept some from becoming sick from bacteria in the water.
From the book Chemical Elements and How They Were Discovered pg 29
