If then our sleep is disturbed by unpleasant dreams, it becomes necessary to investigate the causes. Have we eaten too much or too hurriedly? Are our innermost thoughts clean and wholesome, fit for the light of day? Roman philosophers held that he who wished to obtain knowledge of the will of any of the gods, must fast and lie down to sleep beside the shrine of the god, his thoughts filled with longing and desire for such knowledge. There is more than mere superstition in that. If we abstain from all excesses and are filled with desire to know the will of the gods, dreams, when they come to us, will not disturb or distress us. Dreams are admittedly sometimes prophetic, or have at least an indirect significance touching events not yet come to pass. Galen tells of a man who dreamed that his leg had turned to stone, and a few days later found his leg paralyzed, perhaps an instance of auto-suggestion. Gessner died from a malignant growth which developed in his breast in the exact spot where, a few nights previously, he had dreamed that a serpent bit him; while Aristides, dreaming that he was wounded in the knee by a bull, awoke to find a tumor there. These and many better authenticated cases of dream warnings are not so strange as they seem at first hearing. They may be explained largely by the fact that remote and vague sensations of suffering and disease are able to make deeper impression upon the mind when the interests and activities of the waking life are submerged in sleep. The duration of dreams is another matter of great interest. Most persons feel and say that they “dreamed all night long,” and will proceed to support their statement by relating various incidents of their dreams; their prolonged sensations of pleasure or horror; the events that perhaps covered years. Yet, in reality, the dream may have occupied less than a minute. The dreamer cannot measure the time spent in dreaming, for the unconscious condition of the objective mind obliterates the sense of time, space or material limitations. This accounts for the prodigious feats, the marvels and impossible achievements of dreams that seem to the dreamer in no way disproportionate. What we do know is that some of the most wonderful dreams have occupied but a few moments, and so far scientific research seems to limit them to an hour or two at most. Mohammed’s dream was completed within the time occupied by a falling vase; and it is on record that a man fell asleep just as the clock struck the first stroke of twelve and awoke in a cold sweat on the last stroke, having dreamed that he had spent thirty years in prison, suffering tortures of mind and body. All this makes it easy to understand how, to an infinite mind, a thousand years may be as one day and one day as a thousand years, and how, in our degree, the quiet, self-controlled mind may be unmoved by time.