German physician Paul Ehrlich, a truly eccentric character (for example, he smoked 25 cigars a day and spent hours in pubs discussing philosophy), noticed that various coal-derived dyes stained some tissues and microorganisms, but not others. He correctly deduced that this property would allow a toxic dye to kill tissue that absorbed it without harming tissue that did not. He dubbed his theory “the magic bullet.” He received the Nobel Prize in 1908. His first success was with Trypan I, a red dye used against trypanosomes (parasitic protozoa) in laboratory mice. He then began studying syphilis, caused by the spirochete bacterium. In 1909, after experimenting with 605 different drugs, Ehrlich finally found a compound that was both effective and harmless. It was “number 606,” a compound containing arsenic. Hoechst, where he worked, introduced it to the market in 1910, under the name Salvarsan. Compared to mercury therapy (more torture than therapy) that had been in use for four centuries, this was a huge step forward. Then, in the early 1930s, Gerhard Dogmak of IG Farben developed, using the same method, Prontosil Red, testing it on his daughter. Its antibacterial properties, it was later discovered, were due to sulfanilamide, effective against pneumonia, scarlet fever, and gonorrhea. Hundreds of other variations were produced, and the antibiotics thus obtained saved millions of people from amputations or death during World War II.
