68 THE POPULAR SCIENCE MONTHLY. 



nounced, or when he combines numbers to solve a problem, he 

 does not see the figures, but hears them. " I hear the numbers/' 

 he says distinctly, " and it is my ear that retains them. I hear 

 them sounding in my ear, just as I have pronounced them, in my 

 own voice, and that inner hearing persists through a good part 

 of the day." At another time he told M. Charcot : " Sight is no 

 help to me ; I do not see the figures. I will say even that I have 

 more difficulty in recollecting the figures and the numbers when 

 they are communicated to me in writing than when I receive 

 them by speech. I feel cramped in the former case. I do not 

 care about myself writing the figures. Writing does not help me 

 recollect them. I prefer to hear them." 



His words are confirmed by his actions. When the numbers are 

 given to him written, he pronounces them aloud, putting himself 

 in substantially the same position as if they had been communi- 

 cated to him by the hearing ; then, when he begins his calculation, 

 he turns his eyes away from the written figures, the sight of 

 which, instead of aiding his memory, is only an embarrassment to 

 him. " How can I depend on seeing the figures," he says, " when 

 it is only four years since I learned to read and write ? Yet I 

 calculated mentally before that time." 



Our supposition that M. Inaudi relies on auditive images in 

 his calculations is not absolutely correct. A pure auditive image 

 is very rare. Auditive images and sensations of words are asso- 

 ciated with the motions of the larynx and the mouth required to 

 pronounce them ; and when a person represents to himself a word 

 under the form of a sound, he should at the same time experience 

 special sensations in the organs of phonation, as if the word was 

 about to be pronounced. In other words, so far as concerns lan- 

 guage, the auditive type has the closest connections with the 

 motor type ; the two are often combined. 



This probably takes place with M. Inaudi. We have seen that 

 his lips are not wholly closed when he is at work. They move a 

 little, and an indistinct murmur issues from them, in which we 

 may catch from time to time a few names of figures. The whis- 

 pering sometimes becomes so intense as to be heard several metres 

 off. I have assured myself, by taking the respiratory curve of the 

 subject, that it bears very clear marks of this phenomenon, even 

 when we do not hear it. His sounding organs are then really 

 active while he is calculating in his head. M. Charcot, wishing 

 to determine the importance of these movements, and see what 

 would happen if they were not executed, asked M. Inaudi to 

 make a calculation with his mouth open. But this device did not 

 wholly prevent the motions of articulation, which were still appar- 

 ent. I tried to prevent M. Inaudi from articulating sounds in a 

 low tone, and asked him to sing a vowel during his calculation ; 



