Meaning of 'proverbial worm'

Question

"An appropriate and dramatic end to a singular and yet typical case," said Thorndyke, as he put down the newspaper. "I hope it has enlarged your knowledge, Jervis, and enabled you to form one or two useful corollaries."

"I prefer to hear you sing the medico-legal doxology," I answered, turning upon him like the proverbial worm and grinning derisively (which the worm does not).

[From The Case of Oscar Brodski, by R. Austin Freedman.]

What does a 'proverbial worm' refer to in the above sentence? If it is just a worm, why does Freeman use the word 'proverbial'?

Answer 1

According to The Wordsworth Dictionary of Proverbs (1993), a proverb involving the turning of a worm dates back to at least the middle of the sixteenth century—considerably earlier than the publication date of Shakespeare's Henry VI, Part 3, which Wikipedia dates to 1591. Here is the Wordsworth Dictionary's entry:

Tread on a worm and it will turn. 1546: Heywood, Proverbs, pt. II. ch. iv. , Tread a woorme on the tayle, and it must turne agayne. 1592: Greene, in Works, xii. 143 (Grosart). 1638: Ford, Fancies, V.i., I am, my lord, a worm ; pray, my lord, tread on me, I will not turn again. 1710: S. Palmer. Moral Essays on Proverbs, 305. c. 1800: J. Trusler, Proverbs in Verse, 195. 1816: Scott, Old Mortality, ch. xxvii. 1922: Weyman, Ovington's Bank, ch. ix., The worm will turn, and Thomas ... did turn.

The wording in The Proverbs of John Heywood (1546) is indeed

Tread a woorme on the tayle, and it must turne agayne.

The 1874 edition of that book notes that the quotation from Henry VI, Part 3 runs as follows:

The smallest worm will turn, being trodden on ;

And doves will peck in safe-guard of their brood.

The instance from John Ford, The Fancies (1638) is likewise as reported by Wordsworth.

In any case, the notion that a worm will turn when it is stepped on was already a proverb in 1546, and may well go back considerably farther.

Answer 2

The phrase "proverbial worm" means "the worm in the proverb". In this case the proverb in question is "even a worm will turn", a quote from Shakespeare's Henry VI part 3 (though its use predates that), which implies that the most docile and weak of creatures will fight back if sufficiently provoked. This was once a well-known enough phrase that a native English speaker of the right age (probably assumed by the writer you quote) would recognize it by the allusion in the text.