=Pathological Differences.=--The study of Aphasia (see p. 114) has of late years shown how unexpectedly individuals differ in the use of their imagination. In some the habitual 'thought-stuff,' if one may so call it, is visual; in others it is auditory, articulatory, or motor; in most, perhaps, it is evenly mixed. These are the "indifferents" of Charcot. The same local cerebral injury must needs work different practical results in persons who differ in this way. In one what is thrown out of gear is a much-used brain-tract; in the other an unimportant region is affected. A particularly instructive case was published by Charcot in 1883. The patient was a merchant, an exceedingly accomplished man, but a visualizer of the most exclusive type. Owing to some intra-cerebral accident he suddenly lost all his visual images, and with them much of his intellectual power, without any other perversion of faculty. He soon discovered that he could carry on his affairs by using his memory in an altogether new way, and described clearly the difference between his two conditions. "Every time he returns to A., from which place business often calls him, he seems to himself as if entering a strange city. He views the monuments, houses, and streets with the same surprise as if he saw them for the first time. When asked to describe the principal public place of the town, he answered, 'I know that it is there, but it is impossible to imagine it, and I can tell you nothing about it.'" He can no more remember his wife and children's face than he can remember A. Even after being with them some time they seem unusual to him. He forgets his own face, and once spoke to his image in a mirror, taking it for a stranger. He complains of his loss of feeling for colors. "My wife has black hair, this I know; but I can no more recall its color than I can her person and features." This visual amnesia extends to objects dating from his childhood's years--paternal mansion, etc., forgotten. No other disturbances but this loss of visual images. Now when he seeks something in his correspondence, he must rummage among the letters like other men, until he meets the passage. He can recall only the first few verses of the Iliad, and must _grope_ to recite Homer, Virgil, and Horace. Figures which he adds he must now whisper to himself. He realizes clearly that he must help his memory out with auditory images, which he does with effort. _The words and expressions which he recalls seem now to echo in his ear, an altogether novel sensation for him._ If he wishes to learn by heart anything, a series of phrases for example, he must _read them several times aloud_, so as to impress his ear. When later he repeats the thing in question, the sensation of inward hearing which precedes articulation rises up in his mind. This feeling was formerly unknown to him. Such a man would have suffered relatively little inconvenience if his images for hearing had been those suddenly destroyed.