34 ROYAL SOCIETY OF CANADA 



change of form. In the whole visual field one notices besides— as is 

 known — a certain restless motion. Afterwards single points appear, 

 which are quite bright and move spontaneously and which now follow, 

 no longer a "jumping'' or "flying," but somewhat more a to and fro 

 m^otion. The points combine, here and there with one another forming 

 streaks or lines, these increase rapidly and soon form, in place of the 

 pale violet fixation-region, a lustrous spot, which continually increases. 

 The immediate surroundings of this spot gradually darken to pure 

 black; finally the lustrous spot becomes lost in the black surroundings." 



137. It will be noticed from the above that Zehender describes 

 the spot as being seen near the "fixation-region," and says, that in a 

 certain phase of the phenomenon, the light points have " somewhat a 

 more to and fro motion " — in other respects the phenomenon and that 

 observed by the writer are very dissimilar, especially with regard to 

 the violet spot with toothed limits, and the phase in which the spot 

 increases in size. 



138. In Zehender's last article (Nov. ISTo., citation, par. 127), 

 we find again some points of similarity and some of dissimilarity 

 between the phenomenon described by him as being due to the pigment 

 granules illuminated from behind and the phenomenon seen by the 

 writer ; for instance, he says : — " According to my OAvn experiments, I 

 may assert, that the pigment granules are only visible by night, or in 

 twilight, whereas the circulation of blood is only visible with sufficient 

 brightness (resp. with blinding illumination) and may repeatedly 

 assert, that all pigment motion (perhaps only during a short time) 



.£an entirely or nearly cease." 



139. The image that the writer sees is remarkably constant in 

 its motion, and so far as he has ever observed it has never ceased to 

 keep up this regular motion. Moreover, although the image is, perhaps, 

 not quite as distinct in light as in darkness, it is still visible in the 

 writer's eyes whenever sought, under the proper conditions of back- 

 ground and illumination, Zehender believes the granules to be too 

 thickly piled together and to move with too rapid a motion in daylight 

 to be visible. (The average periodicities observed by the writer are: — 

 for the middle of the night about -685 sees, and for the middle of 

 the day about -450 sees.) 



140. Zehender believes the most " favourable relations " for seeing 

 the pigment granules obtain where there is a coincidence of psychical 

 awakening and the hours of night or early dawn, in which the eye and 

 its pigment apparatus have not yet awakened to a complete activity." 



141. Zehender's article is too long to be completely reviewed in 

 this place, suffice to say that here and there passages occur which would 



