It is quite possible that some of the old Pagan oracles were simply the deceptions of priests by means of ventriloquism.
Dupont, Surgeon-in-chief of the French Army about a century since, examined minutely an individual professing to be a ventriloquist.

With a stuffed fox on his lap near his epigastrium, he imitated a conversation with the fox.

By lying on his belly, and calling to some one supposed to be below the surface of the ground, he would imitate an answer seeming to come from the depths of the earth.

With his belly on the ground he not only made the illusion more complete, but in this way he smothered "the epigastric voice." He was always noticed to place the inanimate objects with which he held conversations near his umbilicus.
Ventriloquists must not be confounded with persons who by means of skilful mechanisms, creatures with movable fauces, etc., imitate ventriloquism.

The latter class are in no sense of the word true ventriloquists, but simulate the anomaly by quickly changing the tones of their voice in rapid succession, and thus seem to make their puppets talk in many different voices.