Or evil custom goading nature so:
Wherefore that miserable valley's race
Have changed their kind to that degree 'twould seem
Circe had pastured them. Among brute swine,
More fit for mast than human food, the stream
Winds its poor way; then, lower down its line,
Finds curs that snarl beyond their power to bite,
And turns from them his nostril as in scorn.
Falling it goes, and more it grows in might,
The curst ditch finds that of those dogs are born