"And possibly," said Faber, "we may find hints to guide us to useful examination, if not to complete solution of problems that, once demonstrated, may lead to discoveries of infinite value,--hints, I say, in two writers of widely opposite genius, Van Helmont and Bacon. Van Helmont, of all the mediaeval mystics, is, in spite of his many extravagant whims, the one whose intellect is the most suggestive to the disciplined reasoners of our day. He supposed that the faculty which he calls Fantasy, and which we familiarly call Imagination,--is invested with the power of creating for itself ideas independent of the senses, each idea clothed in a form fabricated by the imagination, and becoming an operative entity. This notion is so far favoured by modern physiologists, that Lincke reports a case where the eye itself was extirpated; yet the extirpation was followed by the appearance of luminous figures before the orbit. And again, a woman, stone-blind, complained of 'luminous images, with pale colours, before her eyes.' Abercrombie mentions the case 'of a lady quite blind, her eyes being also disorganized and sunk, who never walked out without seeing a little old woman in a red cloak, who seemed to walk before her.'[7] Your favourite authority, the illustrious Miller, who was himself in the habit of 'seeing different images in the field of vision when he lay quietly down to sleep, asserts that these images are not merely presented to the fancy, but that even the images of dreams are really seen,' and that 'any one may satisfy himself of this by accustoming himself regularly to open his eyes when waking after a dream,--the images seen in the dream are then sometimes visible, and can be observed to disappear gradually.' He confirms this statement not only by the result of his own experience, but by the observations made by Spinoza, and the yet higher authority of Aristotle, who accounts for spectral appearance as the internal action of the sense of vision.[8] And this opinion is favoured by Sir David Brewster, whose experience leads him to suggest 'that the objects of mental contemplation may be seen as distinctly as external objects, and will occupy the same local position in the axis of vision as if they had been formed by the agency of light.' Be this as it may, one fact remains,--that images can be seen even by the blind as distinctly and vividly as you and I now see the stream below our feet and the opossums at play upon yonder boughs. Let us come next to some remarkable suggestions of Lord Bacon. In his Natural History, treating of the force of the imagination, and the help it receives 'by one man working by another,' he cites an instance he had witnessed of a kind of juggler, who could tell a person what card he thought of. He mentioned this 'to a pretended learned man, curious in such things,' and this sage said to him, 'It is not the knowledge of the man's thought, for that is proper to God,