"We infected the water supply of Birmingham at its origin in Wales."
I watched his expression intently.
"You mean that you did this secretly, without knowing what the result would be?" he asked at last.
"We foresaw the result to a certain extent."
He thought for some time.
"But you had no right to infect a water supply. That's criminal, surely?"
"It's criminal if the infection is dangerous to people. If you put cholera in a reservoir, of course it's criminal."
"But this germ...?"
"This germ does not kill people. It kills the germs in people."
"What's the difference?"