Frederick Griffith was a British bacteriologist who lived in 1879-1941. In 1928, way before DNA was really discovered, Griffith made an experiment wondering if genetic information could be transferred between different strains of bacteria. It all started when he was studying two strains of Streptococcus pneumoniae which is an illness that can cause pneumonia, ear infections, sinus infections, meningitis, and bacteremia. Both of the strands varied in appearance and virulence (the severity or harmfulness of a disease or poison). Details on the strains would include the S strain having a smooth capsule, or an outer coat composed of polysaccharides. It is also highly virulent, meaning it is very infectious to cause disease. On the other hand, the nonvirulent R strain had a rough appearance and lacked a capsule. He ended up injecting mice with the diseases, and the mice injected with the S strain died very quick (within a few days), while the mice injected with the R strain did not die.