Sang froid

"At the Drones Club and other places I am accustomed to frequent you will often hear comment on Bertram Wooster's self-control or sang froid, as it's sometimes called, and it is generally agreed that this is considerable. In the eyes of many people, I suppose, I seem one of those men of chilled steel you read about, and I'm not saying I'm not. But it is possible to find a chink in my armour, and this can be done by suddenly springing eminent loony-doctors on me in the guise of butlers."