him with the words, "Hail to thee, messenger of God!" He looked round to the right and to the left, but discovered nothing but stones and trees. Soon after this the angel Gabriel appeared to him in a vision on the mountain Hira, and announced to him the message of God. The origin of the hallucination seems to have been in this wise: While walking in the valley meditating in solitude on the degrading idolatry of the people, and girding himself to the resolution to undertake a great work of reform which might well seem beyond his strength, and make him pause, the intense thoughts of his mental agony were suddenly heard by him as a real voice, where there was no voice; and the vision which he saw when he next fell into an epileptic trance was deemed to be the apparition of the angel Gabriel.
If this be so, and much more if all the apparitions and visions which mankind have seen at different times were really hallucinations, it is startling to reflect what a mighty influence illusions have had on the course of human history. One is almost driven to ask in despair whether all in the world is not illusion, whether "all that we see and seem is not a dream within a dream." But there are countervailing considerations which may abate alarm. If a great work in the world has been done in consequence of a vision which was not, as it. was believed to be, a supernatural revelation, but an hallucination produced in accordance with natural laws, the work done, were it good or bad, was none the less real. And inasmuch as the hallucination, whatever its character, is in accordance with the habit of thought and feeling of the person to whom it occurs, and is interpreted, if it be not actually generated, by his manner of thinking, we may put it out of sight as a thing of secondary importance, as an incidental expression, so to speak, of the earnest belief, and fix our minds on this belief as the primary and real agent in the production of the effect. Had Mohammed never seen the angel Gabriel, it is probable that the great mission which he accomplished—the overthrow of idolatry and polytheism and the welding of scattered tribes into a powerful nation—would have been accomplished either by him or by some other prophet, who would have risen up to do what the world had at heart at that time. Had any one else who had not Mohammed's great powers of mind, and who had not prepared himself, as he had done, by many silent hours of meditation and prayer, to take up the reformer's cross, seen the angel Gabriel or any number of angels, he would not have done the mighty work. Who can doubt that the mission of Mohammed was the message of God to the people at that time, as who can doubt that the thunder of the Russian cannon has been the awful message of God to the Mohammedan Turks of this time?
So much, then, for the nature of hallucinations and their principal modes of origin. Although they sometimes originate primarily in the sensory centres, and sometimes primarily in the higher centres of thought, it is very probable that, in many instances, they have a