His instinct of a successful man had taught him long ago that, as a general rule, a reputation is built on manner as much as on achievement.

And he felt that his manner when confronted with the telegram had not been impressive.

He had opened his eyes widely, and had exclaimed "Impossible!" exposing himself thereby to the unanswerable retort of a finger-tip laid forcibly on the telegram which the Assistant Commissioner, after reading it aloud, had flung on the desk.

To be crushed, as it were, under the tip of a forefinger was an unpleasant experience.

Very damaging, too! Furthermore, Chief Inspector Heat was conscious of not having mended matters by allowing himself to express a conviction.
"One thing I can tell you at once: none of our lot had anything to do with this." He was strong in his integrity of a good detective, but he saw now that an impenetrably attentive reserve towards this incident would have served his reputation better.