may witness, according to certain authors, some most amusing disputes. Efforts have been made to trace a mean of designations for the vowels, and to indicate the associations most frequently perceived. It is very doubtful whether such statistics can give important results, and whether the correct association can be got from the majority; for the probability must be recognized of the existence of several types of colored audition, which have not yet been clearly distinguished. Furthermore, persons are most frequently incapable of exactly determining and defining the color that appears to them. Their incapacity is associated with the facts that the shading varies not only with the words, but with the elevation of the voice that pronounces them, its timbre, and its accent, A word never has the same color from two different mouths. Consequently there is no definite red for a or for any other vowel. Some authors have nevertheless published colored diagrams in which the subjects have tried to represent their colored alphabet. These representations may hold good for colors, but not for shades; it is not that the subjects are lacking in good faith, but they can not fix with precision a color that oscillates and is transformed under the influence of a multitude of intangible causes. We can not stop with describing the phenomena, but must explain as far as we can what passes in the minds of the persons who experience impressions of color in connection with sound. What do they mean when they say, for instance, that a appears red to them?
Persons affected with colored audition form a curious illusion respecting their psychological condition. Till the moment, when they are questioned respecting their impressions, they are satisfied that the faculty of coloring sounds is natural, normal, and common to all; and they learn the contrary not without uneasiness. One is never satisfied if he knows that he possesses, deep in his mind, an exceptional trait. All of this kind that is exceptional seems abnormal, and assumes the character of a disease. This opinion is that of many doctors, who would often have much difficulty in defining the condition of psychological health, but imagine that whatever departs from that ideal and imperfectly understood condition is in the domain of pathology. Numerous authors who have written on colored audition have been laudably zealous in comforting those who perceive these impressions. Most—not all of them—have affirmed many times that it is a purely physiological act. We believe they are fundamentally right—but how far?
The phenomenon is often presented in an inexact light. It is easily understood now that it is not a disease of the eyes or the ears, but many authors continue to see in it a disorder of perception, or a double perception, or a confusion of the physiological acts of seeing and hearing.
