Lauren Calso September 29, 2014 BIOL 240 Lab Report Gram Stain Introduction Various methods are used to identify unknown bacteria. A popular method to determine unknown bacteria is called a Gram Stain. A stain is coloring a specimen with dye. A Danish physician named Hans Christian Gram developed the Gram stain method in 1844. He studied at the University of Copenhagen and became a professor of Medicine. When differentiating between two types of pneumonia, he found that most bacteria are either