The best exemplification of what the ancients meant by superstition
is to be found in the lively and dramatic words of Aristotle's great
pupil Theophrastus.

The superstitious man, according to him, after having washed his
hands with lustral water--that is, water in which a torch from the
altar had been quenched--goes about with a laurel-leaf in his mouth,
to keep off evil influences, as the pigs in Devonshire used, in my
youth, to go about with a withe of mountain ash round their necks to
keep off the evil eye. If a weasel crosses his path, he stops, and
either throws three pebbles into the road, or, with the innate
selfishness of fear, lets someone else go before him, and attract to
himself the harm which may ensue. He has a similar dread of a
screech-owl, whom he compliments in the name of its mistress, Pallas
Athene. If he finds a serpent in his house, he sets up an altar to
it. If he pass at a four-cross-way an anointed stone, he pours oil
on it, kneels down, and adores it. If a rat has nibbled one of his
sacks he takes it for a fearful portent--a superstition which Cicero
also mentions. He dare not sit on a tomb, because it would be
assisting at his own funeral. He purifies endlessly his house,
saying that Hecate--that is, the moon--has exercised some malign
influence on it; and many other purifications he observes, of which
I shall only say that they are by their nature plainly, like the
last, meant as preservatives against unseen malarias or contagions,
possible or impossible. He assists every month with his children at
the mysteries of the Orphic priests; and finally, whenever he sees
an epileptic patient, he spits in his own bosom to avert the evil
omen.

I have quoted, I believe, every fact given by Theophrastus; and you