Page:Popular Science Monthly Volume 42.djvu/74

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the other memories remain intact; there are patients who, without 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 memories, 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. Pertinently to this point, a characteristic anecdote is related of Buxton, 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 numbers. 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 difficulty in repeating twenty-four letters. But this was not the case. It was found, not without surprise, that M. Inaudi could not repeat more than seven or eight letters from memory. He hesitated, 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