The Romans furthermore were great observers of dreams; the art of their interpretation belongs to the science of the vital light, to the understanding of its direction and reflections. Men versed in transcendental mathematics are well aware that there can be no image in the absence of light, be it direct, reflected or refracted; and by the direction of the ray, the return under the fold of which they know how to find, they arrive by an exact calculation, and invariably, at the source of light and can estimate its universal or relative force. They take into account also the healthy or diseased state of the visual mechanism, external or internal, and attribute thereto the apparent deformity or rectitude of images. For such persons, dreams are a complete revelation, since dream is a semblance of immortality during that nightly death which we call sleep. In the dream-state we share in the universal life, unconscious of good or evil, time or space. We leap over trees, dance on water, breathe upon prisons and they fall; or alternatively, we are heavy, sad, hunted, chained up—according to the state of our health and often that of our conscience. All this is useful to observe, and unquestionably, but what can be inferred therefrom by those who know nothing and are without the wish to learn? The all-powerful action of harmony, in exalting the soul and giving it rule over the senses, was well known to the ancient sages; but that which they employed to soothe was wrested by enchanters to excite and intoxicate. The sorceresses of Thessaly and of Rome believed that the moon could be dragged from the sky by the barbarous verses which they recited and that it fell pale and bleeding to the earth. The monotony of their recitations, the sweep of their magical wands; their circumambulations about circles, magnetised, excited, and led them by stages to fury, to ecstasy, even to catalepsy itself. In this kind of waking state, they fell into dream, saw tombs open, the air overcast by clouds of demons, the moon falling from heaven.