And he related the cases in fuller detail.
“Odd,” said the doctor. “And you think this may turn out the same way. Still, in this case the death can’t very well have been natural—or why these elaborate efforts to cover it up?”
“It wasn’t,” said Parker; “the proof being that—as we now know—the plot was laid nearly two months ago.”
“But the method!” cried Wimsey, “the method! Hang it all—here are all we people with our brilliant brains and our professional reputations—and this half-trained girl out of a hospital can beat the lot of us. How was it done?”
“It’s probably something so simple and obvious that it’s never occurred to us,” said Parker. “The sort of principle you learn when you’re in the fourth form and never apply to anything. Rudimentary. Like that motor-cycling imbecile we met up at Crofton, who sat in the rain and prayed for help because he’d never heard of an air-lock in his feed. Now I daresay that boy had learnt—What’s the matter with you?”
“My God!” cried Wimsey. He smashed his hand down among the breakfast things, upsetting his cup. “My God! But that’s it! You’ve got it—you’ve done it—Obvious? God Almighty—it doesn’t need a doctor. A garage hand could have told you. People die of it every day. Of course, it was an air-lock in the feed.”
“Bear up, doctor,” said Parker, “he’s always like this when he gets an idea. It wears off in time. D’you mind explaining yourself, old thing?”
Wimsey’s pallid face was flushed. He turned on the doctor.
“Look here,” he said, “the body’s a pumping engine, isn’t it? The jolly old heart pumps the blood round the arteries and back through the veins and so on, doesn’t it? That’s what keeps things working, what? Round and home again in two minutes—that sort of thing?”
“Certainly.”