Be May 1940, Florey's research team dad enough penicillin to experiment with animals fer the first time. In a simple experiment they gave a dangerous bacteria to eight mice. One hour later, they gave penicillin to only four of the mice. After a few hours the four mice with penicillin were fine, but the other four were all dead! When Florey heard of the result the next day he said, 'It looks like a miracle!'