"Doctor, why is it that people get ill?"
He laughed and chuckled at her puzzled frown.
"Well! There's a question to ask a man after his dinner. Do you know it took me the best part of seven years at the hospital to learn the answer? And even now my knowledge is not what you might call exhaustive."
"It seems so queer—mother being ill, and father; then Jean's headaches and my neuralgia. And Wullie all twisted up."
The doctor let the reins drop on the horse's neck and lighted a very old pipe. He had very little chance of a talk, and was glad to talk, even to a girl.
"Just in those people you've mentioned, Marcella, you've almost every cause of illness." He paused, puffed at the pipe and went on, "Wullie—he was born like it."
"Yes. I know. It seems all wrong."
"It is wrong. It's a mistake," said the doctor slowly.
"Whose mistake?" she asked quickly.
"Ah, there you have me, Marcella. It was to answer questions like that that men invented the devil, I believe; they like to say he put the grit in the machine that turned out Wullie, and made him like that out of perversity."