Griffith showed that when mice were injected with a mixture of
living avirulent bacteria are mixed with heat-killed virulent cells,
the mice developed pneumonia and died, and living virulent bacteria were recovered from the blood.
The avirulent bacteria had been transformed into virulent ones.
- Why did Griffith not recover avirulent bacteria from the dead mice?
- The avirulent bacteria were destroyed by phagocytic cells in the host's immune system.
However, a small % were transformed; these multiplied and eventually killed the host.