It's an awfully betraying feature.

So long as it's occupied with politics and the fads and the foibles and the sins and the foolishness and the extravagances of humanity, it's all very well.

But if you ever get in trouble or if ever your heart hurts, or you get mad enough to kill somebody, that mouth of yours is going to be a most awfully revealing feature, Peter.

You will have hard work to settle it down into hard-and-fast noncommittal lines." Peter looked at the girl steadily.
"Have you specialized on my mouth ?" he asked.
"Huh-umph!" said Linda, shaking her head vigorously.

"When I specialize I use a pin and a microscope and go right to the root of matters as I was taught.