English bacteriologist whose studies of pneumococci, the bacteria that cause pneumonia, suggested that bacteria could undergo some kind of genetic transformation. The virulence of pneumococci depends on the presence of a polysaccharide capsule. Virulent strains with a polysaccharide coat were known as type S; bacteria without the capsule were type R. When mice were inoculated with a mixture of living R and heat-killed S bacteria, they became infected. Griffith was able to isolate living S bacteria from these animals. Later researchers proved that the transforming factor was DNA.
"Fred Griffith." Science and Its Times: Understanding the Social Significance of Scientific Discovery. . Encyclopedia.com. (November 15, 2018). https://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/fred-griffith
"Fred Griffith." Science and Its Times: Understanding the Social Significance of Scientific Discovery. . Retrieved November 15, 2018 from Encyclopedia.com: https://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/fred-griffith