While educated as a physician, Manfred Bayer is best known for the series of fundamental contributions he has made to the study of bacterial and viral ultrastructure. He was the first person to visualize the yellow fever virus in cultured cells, and to obtain ultrathin sections of the changes caused to the cell wall of Escherichia coli by the antibiotic penicillin. The latter achievement helped guide the development of future antibiotics active against the bacterial wall. In the 1960s, he identified zones of adhesion between the inner and outer membranes of Escherichia coli. Bayer's rigorous experiments established that these adhesion zones that were apparent in thin sections of cells examined by the technique of transmission electron microscopy had biochemical significance e.g., routing of bacterial components to the surface of the cell, route for passage of viruses into the bacterium, specific site of certain enzyme activity). In recognition...