This molecular specificity, encapsulated so vividly in that reaction between a dye and a cell, began to haunt Ehrlich. In 1882, working with Robert Koch213, he discovered yet another novel chemical stain, this time for mycobacteria, the organisms that Koch had discovered as the cause of tuberculosis. A few years later, Ehrlich found that certain toxins, injected into animals, could generate “antitoxins,” which bound and inactivated poisons with extraordinary specificity (these antitoxins would later be identified as antibodies).
