Pox Doctors Clerk

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This is what the Internet says about the Pox doctor's  clerk

"A Dictionary of Catch Phrases American and British," discusses this one as part of a set including "all dressed up like a Christmas-tree," ". . . like a dog's dinner," ". . . like a ham bone," and ". . . like Mrs. Astor's horse." He says

". . . like a pox-doctor's clerk," i.e., flashily: current since, very approx., c. 1870 . . . G. A. Wilkes, "Dictionary of Australian Colloquialisms," 1978, defines it as 'dressed nattily, but in bad taste', claims it as Aus., . . . but I'm reasonably sure that it went to Australia from England. But 'a pox-doctor's clerk', and its variant 'a horse-doctor's clerk' (without 'like') had, in UK, a different usage: 'These were, in my younger days [1920s-40s] a way of explaining one's occupation if some impertinent person asked what you did for a living' (Anon., letter, 1978)