*M. l'Abbe Forrichon, Le Materialism et la Phrenologie combattues dans lean fondemens, pp. 240, 243, Paris, 1840.

When external and internal sensations reach the brain in a normal state, we are unconscious of their arrival; but if our attention be strongly excited, the material form, the sensible sign may immediately show itself, which leaves no doubt of their presence in the organ. Thus, when we have an intense desire to represent an object, we close our eyes, and it is probable that it will soon appear, confusedly it may be, but yet with sufficient distinctness for us to form an idea of it. A more powerful concentration of thought might allow of our seeing it in daylight, and with open eyes. The image, at first feeble, pale, and indistinct in outline, seems as though it would vanish every moment; but by degrees the outline strengthens, the colors become more vivid, and the perception of the object is complete. Finally, with a still higher degree of meditation, a more entire detachment from the external world, the image which has performed these different evolutions in the brain comes forth, and places itself in a material form before the eyes.

These psychological facts are almost always noticed in individuals devoted to works requiring deep meditation; they are, above all, very common with novelists and poets, who, in their transitions from the real to the ideal world, are often led to take the conceptions of their minds and the products of their imaginations for realities.

* Essay on Apparitions. Attributed to M. Meyer, Professor at the University of Halle, A. D. 1748.

In proportion as their creations are renewed and repeated in the brain, they acquire a degree of vivacity which ends by overpowering all external sensations; and as clearness is the principal quality of a mental conception which makes us believe in the reality of the object represented, it is not surprising that men of deep thought, who concentrate their whole attention on one point, making it a focus of light, should be more exposed than others to similar illusions.

In like circumstances, the mind acquires a more or less powerful excitement in order to produce these illusions; but there are conditions in which they are produced every instant in a much more sensible manner; we would speak of reverie, of the intermediate state between sleeping and waking, and of dreams. It often happens, for example, in dreams, that when an object has been strongly impressed on the mind when awake, it reappears clearly and distinctly during sleep.

It has been asked why the causes of these illusions do not entirely destroy the normal action of the brain. Crichton had replied to this query before Gall wrote: " It is because sensorial impressions, the association of ideas, and the operations of the mind, not all having their seat in that portion of the brain which receives the morbid impression, must continue to exist normally; whence it results that the individual must think and act as a rational man, excepting on the subjects which relate to his illusion." We view the subject in a different manner from the English historian; but, as an historic record, we do not feel at liberty to suppress his explanation.

Prolonged meditation, a great preoccupation of mind, or a powerful or violent emotion may induce similar results.

Observation, in fact, proves, that persons on the point of perishing, have seen the detailed map of their whole lives unrolled before them, thus verifying the passage of Scripture: At the day of judgment, every act will be retraced in the twinkling of an eye. "The last minute of the combatant," says the Arabian proverb, " is the mirror of his life; all that is dear to him is then present to his thoughts."

After intense occupation, where all the faculties have been directed to one point, material forms may remain visible for a length of time, although the subject ceases to engage the mind.

The celebrated artist, Sir Joshua Reynolds, on quitting his study, where he had been many hoars engaged in painting, took the street lamps for trees, and men and women for bushes agitated by the breeze.*

Theory of Attention. - In the psychological analysis of the faculties which exert a more or less marked influence on the production of hallucinations, we have placed attention in the foreground.

It is important, before proceeding farther, that we thoroughly explain the value of the theory to which this faculty serves as a foundation. Viewing it in. relation to the intellectual and moral world, we do not believe in the omnipotence, of the systems which reduce all to one law. The history of philosophy has proved, a thousand times, that if a certain number of facts are in perfect accordance with the new system, another certain number are in direct opposition to it. This, according to our view, is one of the consequences of our finite nature.

We are not, then, surprised that M. Baillarger has declared, in an interesting pamphlet, entitled Hallucinations; their Causes, and the Diseases which they Characterize, that the production of hallucinations is particularly favored by the involuntary exercise of memory and imagination, the suspension of external impressions, and the internal excitation of sensorial organs; or, in other terms, by the weakening, relaxation, and real slackening of attention.

It is evident that the cases cited by this medical observer support his opinion. We will remark that hallucinations produced by reveries, dreams, and the intermediate state between sleeping and waking, have another origin than those attributed by us to intense application of mind. It appears to us equally positive that the visions of the famous painter, Sir Joshua Reynolds, were caused by a fatigued brain.

This point settled, we will now show, by conclusive facts, that, in a great many cases, attention exerts a real influence on the state of hallucination, and perfectly explains the visions and apparitions of many renowned personages.