The dog is turned to his own vomit again; and the sow that was washed to her wallowing in the mire.

-Bible (NewTestament)
Peter 2:22.

As it will be in the future, it was at the birth of Manö There are only four things certain since Social Progress began:ö That the Dog returns to his Vomit and the Sow returns to her Mire, And the burnt Fool's bandaged finger goes wabbling back to the Fire.

-Kipling, (Joseph) Rudyard
  Rudyard Kipling's Verse,'The Gods of the Copybook Headings'.

A starlit or a moonlit dome disdains All that man is, All mere complexities The fury and the mire of human veins.

-Yeats,W(illiam) B(utler)
  'Byzantium', stanza1. Collected in TheWinding Stair and Other Poems (1933).