She spread her hands. “On the morrow. In a moon’s turn.

[1] W. Larden: Optical Illusion. Nature LXIII, 372 (1901).

If, however, the observer finds an inexplicable hiatus in an event he happens to notice, he finds it strange because unintelligible. In this way is created that notion of strangeness which often plays so great a rle in the examination of witnesses. Hence when under otherwise uncomfortable conditions, I see a horse run without hearing the beat of his hoofs, when I see trees sway without feeling any storm; when I meet a man who, in spite of the moonlight, has no shadow, I feel them to be very strange because something is lacking

in their logical development as events. Now, from the moment a thing becomes strange to an individual his perceptions are no longer reliable, it is doubtful whether he knows what he has really experienced before his world became strange to him. Add to this that few people are unwilling to confess that they felt ill at ease, that perhaps they do not even know it,[1] and you get the complicated substitution of sensory illusions and uncanny sensation, the one causing the other, the other magnifying the one, and so on until the whole affair is turned into something quite unrecognizable. So we find ourselves in the presence of one of the inexplicable situations of the reality of which we are assured by the most trustworthy individuals.

[1] H. Gross: Lehrbuch fr den Ausforschungsdienst der Gendarmerie.

To magnify this phenomenon, we need only think of a few slightly abnormal cases. It has already been indicated that there are many such which are not diseased, and further, that many diseased cases occur which are not known as such, at least, as being so much so as to make the judge call in the doctor. This is the more likely because there are frequently, if I may say so, localized diseases which do not exhibit any extraordinary symptoms, at least to laymen, and hence offer no reason for calling in experts. If we set aside all real diseases which are connected with optical illusions as not concerning us, there are still left instances enough. For example, any medical text-book will tell you that morphine fiends and victims of the cocaine habit have very strong tendencies to optical illusions and are often tortured by them. If the disease is sufficiently advanced, such subjects will be recognized by the physician at a single glance. But the layman can not make this immediate diagnosis. He will get the impression that he is dealing with a very nervous invalid, but not with one who is subject to optical illusions. So, we rarely hear from a witness that he knows such people, and certainly not that he is one himself. A very notable oculist, Himly, was the first to have made the observation that in the diseased excitability of the retina every color is a tone higher. Luminous black looks blue, blue looks violet, violet looks red, red looks yellow. Torpor of the retina inverts the substitution.

Dietz[2] tells of color-illusions following upon insignificant indigestion; Foder of hysterics who see everything reversed, and Hoppe[3] says, ``If the order of the rods and cones of the retina is somewhat disturbed by an inflammatory touch, the equilibrium of vision is

[2] ber die Quelle der Sinnestuschungen. Magazin fr Seelenkunde VIII.

[3] Erklrung der Sinnestuschungen. Wurzburg 1888.

altered and changes in size, in form, or appearance occur.'' Naturally the criminalist can not perceive slight indigestion, weak hysteria, or an inflamed area in the retina when he is examining witnesses, yet false observations like those described may have a definite influence upon the decision in a case.