Page:Mind (Old Series) Volume 12.djvu/169

 156 NOTES. if we wish to prove that a subject does not receive an image from our minds we should present to him an object with which we are ourselves unacquainted. But the real difficulty is as regards the minimum visibile. It is usually supposed that in order to produce a definite image more than one retinal cone must be stimulated ; and that consequently no object can be separately discernible which does not subtend (say) an angle of sixty seconds, or whose retinal image is less than (say) '004 mm. in diameter. Floating particles, none of them exceeding '0029 mm. in diameter, have, I believe, been seen as a cloud in a ray of electric light sent through a tube of filtered air, but have never been seen separately by the naked eye. Now the retinal image of an object itself only '06 min. in diameter, and placed within the range of distinct vision, will be much less than '004 mm. in diameter. To bring it up to this minimum the retinal image must be T V of the size of the object itself ; and this implies a nearness to the eye involving mere darkness and blur. The microscopic slide was presumably transparent ; but nothing was said as to the transparency of the photograph, and yet the points distinctly visible on the photograph must have been even smaller than the cells on the slide. A letter with which M. Bergson has favoured me has done much to re- move these difficulties. It seems that the photograph was transparent, and that the boy held it close to his eye. Moreover, after seeing the photo- graph the boy could not read ordinary print. " C'est trop grand," he said; and it was some time before the eye (which M. Bergson believes to have been always myopic query hypermetropic ?) resumed its normal state. It seems, then, conceivable that hypnotic suggestion had induced (by spasm of the ciliary muscle 1) some change in the shape of the crystalline lens, which made the eye a microscope for the time being. Mr. George Wherry has kindly communicated to me two somewhat analogous cases, where ciliary spasm (itself induced by microscopic or telescopic work) led to uniocular diplopia, in one case even triplopia. In these cases -irregular ciliary spasm turned the lens into a kind of multiplying glass : is it possible that M. Bergson induced a regular progressive ciliary spasm, which turned the lens into a powerful magnifier ? Turning back to the question with which we started, the possibility of a hypcrsesthetic explanation of cases of supposed telepathy, I must add that I earnestly hope that the experiments recorded in Phantasms of the Living may receive careful criticism from this point of view. Few, if any of them, will, I think, be found explicable by the cornea-reading discussed above, but there may be other sources of error which have escaped our care. Yet in the hands of some critics hypersesthesia itself assumes attributes almost magi- cal. In the Revue Philosophiquc for December Dr. Ruault maintains that he and others have frequently sent subjects to sleep " by an effort of will " in an adjoining room ; but that the real cause of the sleep was the sugges- tion given by the changed sound accompanying the hypnotiser's quickened circulation, which the subject hears through the wall. This is meant, it seems, to apply to the Havre case, now well known, of sommeil a distance, where Dr. Gibert or M. Pierre Janet can throw Mme. B into the hypnotic trance, " by an effort of will," from their houses to hers. 1 Yet I confess that, whatever may be the true meaning of this curious history, I find it hard to believe that a peasant woman is sent to sleep by " the sound of a going " in the arteries of an elderly physician, at a distance of half a mile. FREDERIC W. H. MYERS. 3 An account of this case will be found in the Proceedings of the Society for Psychical Research, Part x., Art. " Telepathic Hypnotism ".