In 1911 arsphenamine, the first synthetic anti-infective drug, was developed by Paul Ehrlich and chemist Alfred Bertheim of the Institute of Experimental Therapy in Berlin. The drug was given the commercial name Salvarsan. Ehrlich, noting both the general toxicity of arsenic and the selective absorption of certain dyes by bacteria, hypothesized that an arsenic-containing dye with similar selective absorption properties could be used to treat bacterial infections. Arsphenamine was prepared as part of a campaign to synthesize a series of such compounds, and found to exhibit partially selective toxicity. Arsphenamine proved to be the first effective treatment for syphilis, a disease which prior to that time was incurable and led inexorably to severe skin ulceration, neurological damage, and death.[citation needed]
Try to answer this question if possible (otherwise reply "unanswerable"): Bacterial infections could be treated with medicines containing what kind of dye?
arsenic