(ca. 1879 - 1941) A British microbiologist whose research focused on the epidemiology and pathology of bacterial infectious diseases. In 1928, Griffith published his most famous paper, which contained the first widely accepted demonstrations of bacteria changing form and function. His experiments showed the bacteria Streptococcus pneumoniae transforming from one strain to another. His findings encouraged other researchers to try to identify the mechanism by which this change could occur; eventually this research led to the discovery of DNA.