I don’t know how many people are still familiar with the old expression of incredulity “All my eye and Betty Martin” (e.g., from Walter De la Mare’s 1930 On Edge: “You might be suggesting that both shape and scarecrow too were all my eye and Betty Martin”), but there’s a good discussion of it by Mark Liberman over at the Log. The eighteenth century (when it appears to have originated) was at least as fond of folk etymologies as we are today, and there are a couple involving implausible snippets of alleged Church Latin overheard by simple British sailors in foreign parts (or ports): “Ah! mihi, beate Martine” or “Mihi beata mater,” neither of which actually occurs in Catholic ritual (I might add that the mistaking of mihi for “my eye” could only occur with the traditional English pronunciation of Latin, unlikely to have been in use abroad). The truth is that nobody knows or is likely to know how it originated, but it’s an enjoyable phrase and one that I hope will somehow make its way back into the vernacular.
I don’t quite get the meaning of this phrase. Is it like the phrase, “my eye” as in “Earache, my eye!”? (Really I just wanted to get the Cheech and Chong reference in. 🙂 )
I just thought to check the OED, and by George they have an entry (not fully updated since 1933):