Arsenic is of great historic interest. It has been used both as a destroyer and as a savior of mankind. It has fascinated a larger group of men than any other drug substance. The alchemist, the poisoner, the chemist, the toxicologist, the dye manufacturer and the physician have all been familiar with it. It has criminally killed many and accidentally killed a far greater number, yet it has proved a most useful and valuable agent in the service of man. It has contributed greatly to the advance of art and the development of medicine. EARLY HISTORY Arsenic may have been known in the Far East even before the days of Orpheus and Homer, but no direct references to it can be found until the advent of the Hippocratic era. The earliest known forms of arsenic were the sulphides, orpiment and realgar. Hippocrates,1in his chapter on ulcers, mentions the