Which scientist discovered that hydrated ferric oxide is an antidote for arsenic poisoning?

Robert Wilhelm Eberhard Bunsen (1811 -1899) was a German chemist. His name is best remembered for his invention of the clean-burning Bunsen burners used in laboratories worldwide.

He invented the zinc-carbon battery, invented flash photography and with Gustav Kirchhoff invented spectroscopy which they used to discover the elements caesium and rubidium.

In 1834 he published his first important work. Working with the physician Arnold Berthold he discovered an antidote to arsenic poisoning.

He found that adding iron oxide hydrate to a solution in which arsenic compounds are dissolved causes the arsenic compounds to fall out of the solution as ferrous arsenate, which is an insoluble, harmless solid.

Bunsen developed an ongoing passion for studying the compounds of arsenic. He always tried to take precautions against the toxic effects of these compounds. He devised a face mask with a breathing tube that fed him clean air from outdoors while he worked.

Some arsenic compounds, however, are explosive. Without warning, they explode in dry air. In 1843, nine years after finding the antidote to arsenic poisoning, Bunsen became a victim of such an explosion when a sample of an arsenic compound called cacodyl cyanide exploded, shattering his face mask and permanently blinding his right eye.

The explosion also resulted in Bunsen suffering severe arsenic poisoning. He was saved from death by the iron oxide hydrate antidote he discovered nine years earlier.