554 THE POPULAR SCIENCE MONTHLY. 



conception of the solid figure of that jug in a way that no single draw- 

 ing could do. Now, that conception is the result of our early-acquired 

 habit of combining with that which we see that which we feel. That 

 habit is acquired during the first twelve or eighteen months of infancy. 

 When your little children are lying in their cradles and are handling 

 a solid object, a block of wood, or a simple toy, and are holding it at a 

 distance from their eyes, bringing it to their mouth and then carrying 

 it to arm's length, they are going through a most important part 

 of their education that part of their education which consists in the 

 harmonization of the mental impressions derived from sight and those 

 derived from the touch ; and it is by that harmonization that we get 

 that conception of solidity or projection which, when we have once 

 acquired it, we receive from the combination of these two dissimilar 

 pictures alone, or even, in the case of objects familiar to us, without 

 two dissimilar pictures at all the sight of the object suggesting to us 

 the conception of its solidity and of its projection. 



Now, this is a thing so familiar to you, that few of you have prob- 

 ably ever thought of reasoning it out ; and in fact it has only been 

 by the occurrence of cases in which persons have grown to adult age 

 without having acquired this j)ower, from having been born blind and 

 having only received sight by a surgical operation at a comparatively 

 late period, when they could describe things as they saw them I say 

 it is only by such cases that we have come to know how completely 

 dissimilar and separate these two classes of impressions really are, and 

 how important is this process of early infantile education of which I 

 have spoken. A case occurred a few years ago in London where a 

 friend of my own performed an operation upon a young woman who 

 had been born blind, and, though an attempt had been made in early 

 years to cure her, that attempt had failed. She was able just to dis- 

 tinguish large objects, the general shadow, as it were, of large objects 

 without any distinct perception of form, and to distinguish light from 

 darkness. She could work well with her needle by the touch, and 

 could use her scissors and bodkin and other implements by the train- 

 ing of her hand, so to speak, alone. Well, my friend happened to see 

 her, and he examined her eyes, and told her that he thought he could 

 get her sight restored ; at any rate, it was worth a trial. The opera- 

 tion succeeded ; and, being a man of intelligence and quite aware of 

 the interest of such a case, he carefully studied and observed it ; and 

 he completely confirmed all that had been previously laid down by the 

 experience of similar cases. There was one little incident which will 

 give you an idea of the education which is required for what you would 

 suppose is a thing perfectly simple and obvious. She could not dis- 

 tinguish by sight the things that she was perfectly familiar with by 

 the touch, at least when they were first presented to her eyes. She 

 could not recognize even a pair of scissors. Now, you would have 

 supposed that a pair of scissors, of all things in the world, having been 



