Turn a hair

If in some hideous dissecting-room or fetid laboratory you found this man lying on a leaden table with red gutters scooped out in it, you would simply look upon him as an admirable subject. You would not turn a hair.

[…] those seasoned topers who drank their companions under the table without themselves turning a hair […]

[…] they all went into a shop that Jennifer alone would never have dreamed of entering, and looked at watches; finally Jane bought a gold self-winding wrist-watch for her husband for ninety-two guineas, and never turned a hair.