When the new Bill is passed, people will be obliged to use the Bulton Filter in any case."

"I see," said Hood reflectvely. "You first make a mess of the water for money, and then make a virtue of forcing people to clean it themselves."

"I don't know what you're talking about," said Hunter angrily.

"Well, I was thinking at the moment," said Hood in his rather cryptic way. "I was thinking about Mr. Bulton. The man who owns the filters. I was wondering whether he might join us. We seem such a happy family party."

"I cannot see the use of prolonging this preposterous conversation," said Sir Samuel.

"Don't call the poor Professor's theory preposterous," remonstrated Hood. "A little fanciful, perhaps. And as for the doctor's view, surely there's nothing preposterous in that. You don't think the chemicals will poison all the fish I catch, do you, Doctor?"

"No, of course not," replied Hunter curtly.

"They will adapt themselves by natural selection," said Hood dreamily. "They will develop organs suitable to an oily environment—will learn to love petrol."

"Oh, I have no time for this nonsense," said Hunter, and was turning to go, when Hood