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THE POPULAR SCIENCE MONTHLY. 



sight 



Fig. 6. — The Location op the Memory-Pictures in the Men- 

 tal Image op a Rose on the Brain Surface. The different 

 memory-pictures are joiDed by association fibers. 



We are constantly increasing our store of mental images, and 

 when one contrasts the small number of such images in the brain 

 of a common uneducated day -laborer with the myriads in the 

 brain of one who has traveled widely, has become familiar with 



the stores of informa- 

 tion in foreign lan- 

 guages as well as in 

 his own, and has cul- 

 tivated his powers of 

 observation in many 

 different directions 

 — for example, such 

 a great leader of 

 thought as Glad- 

 stone — one can not 

 but be amazed at the 

 capacity of work in 

 this little organ, the 

 brain. And if there 

 is a physical basis for 

 each of these mental 

 images, is it not evi- 

 dent that in the brain of a Gladstone large areas must be taken 

 up which in the laboring man are really empty ? We have seen 

 that on our brain-map there are some empty spaces. There is 

 every reason to believe that these grow smaller as our information 

 widens ; and, if so, then, like the undiscovered country of Africa, 

 they should really be a stimulus to efforts of further conquest. 



But this mental image of the rose, as represented in the figure, 

 is not really a complete image until it is associated with a name. 

 And the mental image of the name is not as simple as might at 

 first be supposed ; for you have not only learned to recognize the 

 word " rose " when you hear it, or when you see it printed, but 

 you have also learned to say the word and to write it, so that you 

 really have a word-image " rose " made up of two sensory images, 

 auditory and visual, and of two motor images, or the memory of 

 the effort necessary to use the word in speech and in script. It 

 is necessary to add then four more circles to the diagram to show 

 the physical basis of the word " rose," and each of these must be 

 placed in its own special region, which has been determined by a 

 long series of investigations. These circles, too, must be joined 

 together, since all the parts of the word are connected in the mind ; 

 and, finally, the word-image and the mental image, in all their parts, 

 must also be associated (Fig. 7). Thus the complete mental image 

 of such a simple object as a rose is made up of numerous distinct 

 mental pictures, each joined to all the others, and each located in 



