Edward Marsh, Ambrosia and Small Beer (New York: Harcourt, Brace and World, 1965), p. 220—
A soldier up for medical exam proved to have been wearing a truss for the last 6 years, and was classiﬁed as P.E. or Permanently Exempt. On his way out he gave this news to his pal, who immediately asked for the loan of the truss, which was granted. The examiner asked how long he had been wearing it, and he said, "Six years," whereupon he was classiﬁed as M.E. "What's that?" he asked. "Middle East." "How can I go to the Middle East when I've been wearing a truss for 6 years?" "If you can wear a truss for 6 years upside-down, you can jolly well ride a camel for 6 months."