Question

In Griffith's Experiment 3, mice were injected with heat-killed S strain bacteria. What occurred?

Options

• Mice died of pneumonia

• Mice survived

• Mice became transformed into S strain carriers

• Mice developed temporary immunity

Answer 1

When S strain bacteria were killed by heat treatment and then injected into mice, the mice survived. This demonstrated that heat inactivates the bacteria and destroys virulence, and dead bacteria alone are incapable of causing disease.