I have found that the peculiarities of visualisation, such as the tendency to see Number-Forms, and the still rarer tendency to associate colour with sound, is strongly hereditary, and I should infer, what facts seem to confirm, that the tendency to be a seer of visions is equally so.  Under these circumstances we should expect that it would be unequally developed in different races, and that a large natural gift of the visionary faculty might become characteristic not only of certain families, as among the second-sight seers of Scotland, but of certain races, as that of the Gipsies.

It happens that the mere acts of fasting, of want of sleep, and of solitary musing, are severally conducive to visions.  I have myself been told of cases in which persons accidentally long deprived of food became for a brief time subject to them.  One was of a pleasure party driven out to sea, and not being able to reach the coast till nightfall, at a place where they got shelter but nothing to eat.  They were mentally at ease and conscious of safety, but all were troubled with visions that were half dreams and half hallucinations.  The cases of visions following protracted wakefulness are well known, and I have collected a few of them myself.  I have already spoken of the maddening effect of solitariness:  its influence may be inferred from the recognised advantages of social amusements in the treatment of the insane.  It follows that the spiritual discipline undergone for purposes of self-control and self-mortification, have also the incidental effect of producing visions.  It is to be expected that these should often bear a close relation to the prevalent subjects of thought, and although they may be really no more than the products of one portion of the brain, which another portion of the same brain is engaged in contemplating, they often, through error, receive a religious sanction.  This is notably the case among half-civilised races.

The number of great men who have been once, twice, or more frequently, subject to hallucinations is considerable.  A list, to which it would be easy to make large additions, is given by Brierre de Boismont (Hallucinations, etc., 1862), from whom I translate the following account of the star of the first Napoleon, which he heard, second-hand, from General Rapp:—­

“In 1806 General Rapp, on his return from the siege of Dantzic, having occasion to speak to the Emperor, entered his study without being announced.  He found him so absorbed that his entry was unperceived.  The General seeing the Emperor continue motionless, thought he might be ill, and purposely made a noise.  Napoleon immediately roused himself, and without any preamble, seizing Rapp by the arm, said to him, pointing to the sky, ‘Look there, up there.’  The General remained silent, but on being asked a second time, he answered that he perceived nothing.  ‘What!’ replied the Emperor, ‘you do not see it?  It is my star, it is before you, brilliant;’ then animating by degrees, he cried out, ’it has never abandoned me, I see it on all great occasions, it commands me to go forward, and it is a constant sign of good fortune to me.’”