SOME SENSE DEFECTS PSYCHOLOGICALLY CONSIDERED. 55 1 



The phenomenon of slow siorht is, I presume, due to some 

 skigo-ishness in nerve-current, and not to the state of the nerve- 

 ending. I have known people complain of it whose sight was 

 quite normal otherwise. It obviously provides a question of 

 importance for psychology, but I do not see it treated in the 

 text-books. Personally, it has been a source oif much incon- 

 venience to me. I have, for example, when walking fast, met 

 a lady of my acquaintance. I have seen her bow, and seen the 

 expression of annoyance at my lack of response — ^but all after 

 I had passed. 



Now there is a " test " one reads of for estimating power 

 of observation : it consists of making people pass a shop window, 

 previously unseen, and of recording the number of objects they 

 can assert they have seen. In my case the verdict would un- 

 doubtedly be " below par." But as through life I have habitually 

 observed Nature more effectively than most o^f m}- companions. 

 I venture to think this " test " quite fallacious. 



There are two qualities in my vision which seem to be in- 

 consistent with what I have said, viz., sensitiveness to movement 

 and to colour. I suppose our sense-organization admits of 

 inconsistencies as much as our mind does. No one is quite 

 logical throughout. 



As to movement, there used to be in the north window 

 of our cathedral a hole which sent an image of the sun on to 

 our sanctuary. The image was an elli]:)se of about two sciuare 

 feet in area. Whenever I looked at this image, as it shone on 

 the white steps of the sanctuary. I always got a first impression 

 that it was flozvhicj down the steps. When I looked hard at it, 

 the movement could no longer be seen ; though it was easily 

 measurable at intervals of three or four seconds. The impres- 

 sion quite startled me the first time, but it was always repeated, 

 and I am quite sure of mv statement. Again, going once with 

 the Mountain Club tO' the Tulljagh Waterfall, I was Avalking 

 Avith a ])erson of normal sight, an oculist, by the way, and sud- 

 denly at a bend I saw a white moving streak. " The Fall," I 

 cried. " Nonsense,'" said he. " it is the white trunk of a tree. ' 

 '■ But I see it moving," I ]3ersisted. And we walked quite a 

 hundred yards before he could see the movement. [N.B. — I 

 must have been helped to confidence in contradicting him by 

 the knowledge that no tree with such a white trunk could possi- 

 bly be growing in that locality ; but the movement I distinctly 

 saw, and that far beyond my range of vision of form.] This 

 was very useful to me once in science. I was collecting insects 

 in South Rhodesia, and the train made a long stop at a place 

 where, as far as the eye could reach, there was only one tree 

 (an acacia) on the grass veld. I knew there would be something 

 on that tree, and made for it. I examined leaves, twigs, branches 

 and trunk, but in vain. After at least twenty minutes, I gave 

 up in despair and turned away. But, knowing the wary habits 

 of our wild life, I turned sharply back after going two or three 

 steps. There was a minute, but unmistakable, movement. I 



