Summarize the experiment in which griffith became aware that hereditary information could be transmitted between two organisms in an unusual manner.

In his experiment, Griffith used two strains of  Streptococcus pneumoniae type II- rough(R) strain and a type III smooth(S) strain. The type III smooth strain had an outer polysaccharide capsule which makes smooth strain a virulent strain.

So in his experiment, Griffith injected these strains in mice in an order and observed the result. When he  

injected living S strain- Mice died

Injected living R- strain- Mice survived

Injected heat-killed S strain- Mice survived

Injected heat S strain+ living R strain- Mice died

So after his experiment, he concluded that R strain took something from heat killed S strain which transformed the R strain into virulent strain that killed the Mice. So based on this experiment Griffith gave transformation principle.