A whistle

“As clean as a whistle?” The phrase originated in the early 1900’s and is probably derived from an earlier expression: “As clear as a whistle.” Which referred to the clarity of a whistling sound and how far the high pitched noise would travel.

Panic

“One can usually panic about only one or two things at a time.” Theodore Dalrymple, Mass Lysteria 1988 Subtitle “The Meaning of Health Scares”