In pathological states, as in the normal state, auditory sensations occupy a position of primary importance among the psychic functions; thus, of all hallucinations those of hearing are clinically the most frequent and the most important.

Seglas 1 classifies them in three categories: "Elementary auditory hallucinations, consisting of simple sounds; common auditory hallucinations, consisting of sounds referable to definite objects; and verbal auditory hallucinations, consisting of words repesenting ideas."

Wernicke2 combines the first two categories under the name of akoasms, and designates the third, the only one that seems to him to merit separate consideration, by the name of phonemes.

Akoasms comprise imaginary noises of a variable nature, such as buzzing, whistling, screaming, groaning, ringing of bells, explosions of firearms, etc. Their clinical significance is the same as that of hallucinations in general, and their influence upon the mind depends upon their interpretation by the patient.

Phonemes (the verbal auditory hallucinations of Seglas) have on the contrary a special significance, inasmuch as they consist of "words representing ideas." Their influence is much more direct and much more powerful than that of akoasms.

1 Lecons cliniques sur les maladies mentales et nerveuses, p. 5. - Pathoge'nie et physiologie pathologique de l'hallucination de I'oute. Congres des medecins alienistes et ueurologistes, 1897.

2 Lcc. cit, p. 189.

Their content varies from isolated words to the most complicated discourses. Sometimes the words or phrases are pronounced indistinctly, resembling a faint murmur; at other times they are perceived with remarkable clearness. "It seems to me," patients often say, "that somebody is speaking very near me. . . .1 hear my enemies as well as I hear you." This distinctness largely accounts for their being accepted as real voices, and explains partly the remarkable influence of auditory hallucinations.

The "invisible ones," as the patients often call the imaginary voices, are sometimes localized with extraordinary precision. "The insane manifest a power of localization not encountered in other than pathological states." l The distance at which they believe they hear the voices is very variable; the voices may be very close by or, on the contrary, hundreds of miles away. Many patients hold the persons that are around them responsible for the hallucinations; thus are explained some of the sudden assaults often committed by such patients. Others ascribe their hallucinations to inanimate objects. One patient accused her needle, another her stockings. Still others lay the blame upon invisible instruments which are used by their enemies (phonographs, telephones, megaphones, etc.).

Like all other hallucinations, those of hearing vary with the nature of the mental trouble; sad in the painful states, agreeable and cheerful in the expansive states. Usually the names by which the patients designate the " invisible ones " are not very choice ones, consisting chiefly of profane or even filthy expressions. Unpleasant hallucinations may alternate with agreeable ones in the manner of attack and defense, as has already been stated. Sometimes each of the two varieties of hallucinations is perceived by only one ear.

The voices may repeat the thoughts of the patient, even before he has a chance to express them. "They know before I do what reply I wish to make," said one such patient. Another said: "When I read they read at the same time and repeat every word." Many complain that their thoughts are stolen from them.1

1 Wernicke, Loc. cit., p. 205.

Quite often the voices create neologisms the meaning of which may remain absolutely enigmatical to the patient himself, or to which he may attribute a significance which harmonizes with his psychic state.

The timbre of the voices is very variable. In some cases the patient always perceives one and the same voice; but more frequently many voices are heard: voices of men, women, and children, which are sometimes unknown to the patient, at other times familiar, enabling him to establish the identity of his persecutors.

Although they are encountered in a great many mental affections, acute and chronic, hallucinations of hearing, if they constitute a prominent feature by reason of their multiplicity, distinctness, or intensity, usually point to a grave prognosis. Their occurrence in an acute psychosis often forebodes a particularly long duration of the disease.