Nor are the writers and persons who traffic in works of the imagination generally the only ones who take cognizance of day-dreams, reveries or hallucinations, as the term may be chosen and applied. Frederick Greenwood, the author of "Imagination in Dreams," mentions frequently seeing a shower of scintillations that would transform themselves into a flock of sheep that ran downhill.

Johann Muller, the priest who abandoned his sacred calling for the pursuit of the science of physiology, could conjure up the vision of flowers at will.

Napoleon also had day-dreams in which figures appeared to him and told him what to do.

Abraham Lincoln gives this description of one of his daylight visions: "... I went upstairs to Mrs. Lincoln's reading-room. Feeling somewhat tired I lay down upon a couch in the room, directly opposite a bureau upon which was a looking-glass. As I reclined my eye fell upon the glass, and I saw distinctly two images of myself, exactly alike, except that one was a little paler than the other. I arose and lay down again with the same result." - The True Abraham Lincoln, William E. Curtis.

It is authoritatively stated that the solution of the problem of the telegraph code came to S. F. B. Morse as he lay in a state of profound abstraction, in other words a waking dream.

The most triumphant instances in favor of the theory of day-dreams, however, are those of Professor Huxley and of Weir Mitchell respectively.

The great nerve specialist says that he himself has seen faces in the dark ever since boyhood, and that these faces disappear as soon as the eyes are opened.

Thomas Henry Huxley, the English scientist, calls the voices that he heard "auditory hallucinations" ("Elementary Lessons in Physiology," p. 267), yet nevertheless he acknowledges having heard them as distinctly as the maddest poet who ever wrote a rhyme, or heard the "voices of the soul."

Despite Weir Mitchell and Huxley as exponents of the auditory hallucination, the visual dreams are considered as more wholesome and farther from the "way that madness lies." While internal voices are frequent visitors of patients in asylums, who complain that their thoughts are spoken to them aloud and that confused voices shout and set them various impossible tasks, hallucinations of sight unless produced by fatigue or by artificial means are not regarded as particularly symptomatic of mental disease. It is no unusual gift, for instance, for portrait painters to be able to summon at will a mental picture of the sitter, while a mere line will often conjure an entire scene for a landscapist. It is said that Turner, the master of color, would spend hours gazing into space apparently watching nothing, yet in reality seeing colors that were lost upon the ordinary vision.

"Materialism brings the accusation that occultism, mysticism and other faiths that encourage the cultivation of supernormal seeing and hearing have a tendency to overcultivate an abstraction that leads towards hallucination. The accusation is probably largely due to partisan exaggeration, yet that the condition has arisen is undeniable. An interesting example is that of Vilgard, the grammarian of the tenth century who became so infatuated with the pagan poets that their figures moved through his dreams and asleep or awake he heard their thanks and their assurances that he should participate in their glory. In his enthusiasm he taught matters prohibited by the Christian faith and was consequently condemned as a heretic Others we are told became infected by his opinions and perished by sword and fire, for those were the days of compulsory Christianity." - Medieval Mind, Taylor.

Abstraction, though frequently confused with reverie and with day-dreaming, is in fact their polarity. In reverie there is always more or less difficulty in fixing the mind upon a particular subject, whereas in abstraction the mind is concentrated with such firmness that it can not be withdrawn.

"Abstraction," says the occultist, "is the faculty by which man rules nature."

Sir Isaac Newton, who in his abstraction made a tobacco stopper of a lady's finger, and Archimedes, intent on a problem and remaining unconscious during the noise attending the capture of Syracuse, illustrate entire abstraction.

Sonambulism, though a distinct phenomenon of sleep, scarcely comes under the head of dreaming; there is really a wider chasm between the conditions of somnambulism and of dreaming, than there is between the day dream and that of the night. If a dreamer be suddenly waked he will tell his dream, whereas if a sleep-walker be roused, he will have no recollection whatever of his dream state; it is therefore sometimes contended that somnambulism is a deeper sleep than that of the dream slumber, and that it goes lower into the depths of the subconsciousness than the ordinary dream, and that for this reason the sleep-walker rarely comes to harm while in the somnambulistic state. On the other hand, many physicians hold that sleep-walking is due to chorea, a nervous disease.

In ordinary slumber, the sense of sight seems to be the only one of the five senses irrevocably closed; in somnambulism, on the contrary, the eyes are wide open, though whether the subject actually sees is an unsolved riddle, as no somnambulist has ever been known to recall his state of mind as a sleepwalker. Though their action seems automatic, there is a certain method in the movements of somnambulism, and the actions are commonly those that have been suggested in the waking state. Sleep-walking usually occurs in the early night, whereas we are told that the important dreams take place in the early morning. Certain forms of somnambulism may become automatic. MacNish mentions that the soldiers of Sir John Moore, who frequently marched all night, many of them fell asleep upon the march although they continued to walk with their comrades.

One of the most remarkable somnambulistic feats on record is that of Condillac, tutor of the infant Duke of Parma, nephew of Louis XV: this zealous teacher wrote the greater part of his "Cours Complet d'Instruction," a remarkable work including a grammar, and elementary lectures on the arts of writing, history, reasoning and thinking, in a state of somnambulism.