64 THE POPULAR SCIENCE MONTHLY. 



the other memories remain intact ; there are patients who, with- 

 out being paralyzed, can no longer write, but continue to speak ; 

 others lose the faculty of reading while they keep that of writing, 

 so that they can not read the letter they have just written. 



The study of arithmetical prodigies presents the same question 

 under another aspect : no memory is destroyed in them ; but one 

 of the memories, that of figures, acquires an abnormal extension 

 that excites enthusiasm and admiration, while the other memo- 

 ries, regarded as a whole, present nothing peculiar. They even 

 sometimes continue below the common grade. Subjects of this 

 class are real specialists who interest themselves during the 

 whole course of their existence in but one thing — numbers. Per- 

 tinently to this point, a characteristic anecdote is related of Bux- 

 ton, a celebrated calculator, who was taken to a performance by 

 Garrick. At the conclusion of the play he was asked what he 

 thought of the piece. He replied that a certain actor had entered 

 and made his exit so many times, and had pronounced so many 

 words, and so on. That was all the recollection he had of the 

 play. The committee of the Academy has taken the measure of 

 the different kinds of memory in M. Inaudi, and has concluded 

 that he has not a greatly developed memory for forms, events, 

 places, or musical airs, and I have found that his memory for 

 colors is very weak. He gives surprising results only in num- 

 bers. This inequality in the development of memories assumes a 

 remarkable character when we compare in him two things nearly 

 identical, the memory for figures and that for letters. A series 

 of letters was pronounced in his presence which he was asked to 

 repeat exactly, and the same was done for figures. It would seem 

 at first sight that the articulated sound of a pronounced letter 

 would be as easy to hold in the ear as that of a figure, so that a 

 person capable of repeating, for example, twenty-four figures, as 

 M. Inaudi does without much effort, would have no more diffi- 

 culty in repeating twenty-four letters. But this was not the case. 

 It was found, not without surprise, that M. Inaudi could not re- 

 peat more than seven or eight letters from memory. He hesi- 

 tated, lost his usual self-possession, and wanted to withdraw from 

 the experiment ; and when two lines of French were read to him, 

 he could not repeat them exactly after a single hearing. 



The recollection of the figures is a necessity for every mental 

 calculator. It is of service to him, first in retaining the details of 

 the problem, and then in retaining the partial solutions till the 

 complete solution is found. The complexity of the problems 

 which a person can hold in his head gives an idea of his memory. 

 But there is a more direct and simpler means to measure the 

 extent of the memory for figures, and that is to cause him to 

 repeat a series of figures, seeking to find by trial the maximum 



