Hans Christian Gram  The man who made the bacteria colorful  Bacterial diseases help antibiotics - logically. But how did you succeed in making the pathogen of pneumonia visible? That's where Hans Christian Gram comes into play The beard bearer is Hans Christian Gram. 166 years ago, the bacteriologist was born in Copenhagen, Denmark. Google honored him with a doodle for the occasion. But what exactly should the drawing represent? And why do Gram's findings still have relevance today? In his statement, Google refers to a series of experiments that Gram conducted between 1883 and 1885 in Berlin. They helped to make certain pathogens visible - and in this way the healing - and to increase prevention possibilities drastically. In simple terms, Gram has succeeded in dividing bacteria into two groups by a novel staining method: Gram-positive and Gram-negative bacteria. The difference lies primarily in the way the cell walls are constructed. In gr