In his experiment, Griffith infected mice with the S strain and with the R strain. The mouse with the S strain died, while the one that received the R strain survived. He then heat-killed the S strain and administered it to a mouse. The mouse survived. The next step in his experimental processed was to combine heat-killed S strain and live R strain, which he gave to the mouse. The mouse died! Through this he concluded that the dead S strain must have given the live R strain something, which he called a transforming factor. The experiment is summarized by this picture:
Through other experiments scientists discovered this transforming factor was in fact DNA. Frederick Griffith is a very important person in the history of genetics!
Do you know how Frederick Griffith died? Do you know why the S strain was deadly and why the R strain was not? Also, does this post count as double, for F and G?! Just kidding. You're still getting a G :)