55-^ SOME SENSE DEFECTS PSVCIIOLOGICALLY CONSIDERED. 



nishecl back to the spot and found (|uite a large beetle, sha|)ed 

 much like a piece of the bark, and snuggling^ into the crevice 

 to add to the illusion. Moreover, however he had done it, the 

 rogue had further caiuoiiflaycd himself by pasting little bits of 

 bark on his back. Once I found him, it was easy to tind other 

 little " bits of bark " of the same shape, and I gathered in about 

 a dozen of them — all because that one had not been able to 

 refrain from shi)uting " Hurrah !" with his antennae too soon. 



Sensitiveness to colour has stood me in e(|ually good stead." 

 No one could believe what the blue of the Aris'tca on the Paarl 

 mountain meant to me in my early childhood. A stranger walk- 

 ing with me once pointed about a hundred yards ahead to some 

 flowers that struck him. " Homeria collina," I said. " But," 

 said he, " I shouldn't have thought 3'ou could even see there was 

 a flower there." " No more can I." I replied, " but I see a 

 splash of colour, salmon pink, and no other flower of that colour 

 grows here." Again, walking wnth a doctor once round the 

 Kloof, with a clear sun declining in the west and a mist over the 

 last buttress of the Table, I pointed suddenly and said. '" How 

 lovely the rainbow colours are when mingling Avith the A-egeta- 

 tion." He looked carefully, and then turned to me: "There's 

 nothing there: pure imagination: you had better mind or you' 

 will be getting hallucinations one of these days." Just then the 

 sun shone out more clearly, and the rainbow finished all over 

 the sky. I never saw a man more taken aback. Moreover, 

 when I lift my arm in the sunlight. I can distinctlv see the 

 iridescence of the small fibres on the surface of my black coat, 

 though I cannot see when my coat needs brushing or cleaning. 



Now, these two points, and I suppose there are others, 

 have to be taken into account before a psychologist dogmatises 

 about " power of observation." 



The defect of near-sight with me is a form of astigmatism, 

 the results of which seem not to be commonly known. At least 

 I find them in no ibook within my reach, and even medical men 

 sometimes seem surprised when I talk of clear multiple vision 

 Avith a single eye. Perhaps therefore it is worth describing. 



The defect lies in the cornea (or ifront of the eye) rather 

 than in the lens. The bulge of the cornea (which I can 

 feel with my finger through the eyelid) causes a parallel ray to 

 be refracted at very various angles on to the lens. Each little 

 region comes to its owai focus on the retina, and the result is 

 between 50 and 100 images of a candle-flame ( sa}^) arranged in 

 a circle, but so superposed as to lose all outline. This is why 

 near-sighted people (as I discovered for myself very early in life) 

 find their vision cleared by looking through a pin-hole in a card : 

 it cuts ofi:" all except the few central images, and the true outline 

 becomes perceptible. As years went on, and the bulge of the 

 cornea increased, the images came to be set further and further 

 apart, until one day, while experimenting with a small electric 

 light, I happened to look at it with my spectacles oft. and to 



