The History of Tom Jones by Henry Fielding

When Mr Allworthy had retired to his study with Jenny Jones, as hath been seen, Mrs Bridget, with the good housekeeper, had betaken themselves to a post next adjoining to the said study; whence, through the conveyance of a keyhole, they sucked in at their ears the instructive lecture delivered by Mr Allworthy, together with the answers of Jenny, and indeed every other particular which passed in the last chapter.

This hole in her brother's study-door was indeed as well known to Mrs Bridget, and had been as frequently applied to by her, as the famous hole in the wall was by Thisbe of old. This served to many good purposes. For by such means Mrs Bridget became often acquainted with her brother's inclinations, without giving him the trouble of repeating them to her. It is true, some inconveniences attended this intercourse, and she had sometimes reason to cry out with Thisbe, in Shakspeare, "O, wicked, wicked wall! " For as Mr Allworthy was a justice of peace, certain things occurred in examinations concerning bastards, and such like, which are apt to give great offence to the chaste ears of virgins, especially when they approach the age of forty, as was the case of Mrs Bridget. However, she had, on such occasions, the advantage of concealing her blushes from the eyes of men; and _De non apparentibus, et non existentibus eadem est ratio_ -- in English, "When a woman is not seen to blush, she doth not blush at all."