Some individuals possess the power of producing hallucinations at will. Goethe had that power. "As I shut my eyes," he said, "and lower my head I figure to myself a flower in the center of my visual organ; this flower does not retain for an instant its original form; it forthwith rearranges itself and from its interior appear other flowers with multicolored or sometimes green petals; they are not natural flowers, but fantastic, though regular, figures like the rosettes of the sculptors. It is impossible for me to fix the creation, but it lasts as long as I desire without increasing or diminishing.

In the great majority of cases the judgment, itself disordered, is unable to correct the psychosensory error: the hallucination is taken for a true perception. Though sometimes in the beginning of the disease the subject experiences some doubts, this transitory incertitude is soon replaced by a blind belief in the imaginary perception. "We observe," says Wernicke, "that the reality of a hallucination is maintained against the testimony of all the other senses, and that the patient resorts to the most fantastic explanations, rather than admit any doubt as to the reality of his perception." 2 An individual, alone in the open field, hears a voice calling him a thief. He will invent the most absurd hypotheses rather than believe himself a victim of a pathological disorder.

Certain patients, chiefly the weak-minded and the demented, accept their hallucinations without inquiring

1 Jean Muller. Loc cit.

2 Wernicke.

Grundriss der Psychiatrie, p. 126.

as to their origin or mechanism; others on the contrary strive to give explanations which vary with the nature of the malady, the degree of the patient's education and intelligence, and the current ideas of the times. In the middle ages psychosensory disorders were often attributed to diabolic intervention, and this not only by patients but also by their friends. Patients of our own times mostly resort for explanations to the great modern inventions (electric currents, telephone, X-rays, wireless telegraphy, etc.). Some fancy to themselves apparatus or imaginary forces. One patient attributed his disturbances of general sensibility to a "magnetoelectro-psychologic" current. Another received the visions from a "theologico-celestial projector."

Affectivity.—Hallucinations are sometimes agreeable, at other times painful, and occasionally, chiefly in dements, indifferent.

In the first case their outward manifestations are an appearance of satisfaction, an expression of happiness, and sometimes ecstatic attitudes.

In the second case, which is the most frequent, the patients become sad, gloomy, or, on the contrary, agitated and violent, a prey to anxiety or anger.

The two kinds of hallucinations, agreeable and painful, are occasionally encountered in the same subject. Sometimes they follow each other without any regular order and are coupled with a variable disposition and incoherent delusions, as in maniacs and in general paretics; at other times they follow each other somewhat systematically the painful hallucinations are combated by the agreeable ones. The patients

often speak of their persecutors, who insult, threaten, and abuse them, and of their defenders who console them, reassure them, and repair the damage done by the former. A persecuted patient heard a voice call her "a slut"; immediately another voice responded, "He lies; she is a brave woman." Some patients tell of their limbs being smashed and their viscera extracted every night, but that nevertheless they are sound and safe when they arise, thanks to the good offices of their defenders, who properly replace everything. These two sets of hallucinations constitute what the patients sometimes call the attack and the defense.

The indifferent hallucinations are of but little interest. They are met with at the terminal periods of processes of deterioration, and also at the beginning of convalescence in acute psychoses. In the latter case they rapidly become conscious hallucinations and finally disappear.

Reactions. The influence of hallucinations upon the will depends upon the state of the judgment and of the affectivity. If the judgment is sound, if the hallucinations are looked upon as pathological phenomena, they give rise to no reaction; and the same is the case when they make no impression upon the emotions.

But when they are accepted by the patient as real perceptions and influence strongly the emotional state, hallucinations, on the contrary, govern the will to a very considerable extent and prompt the patient to defend himself against the ill-treatment of which he believes himself to be the object or to obey the commands which are given him (imperative hallucinations).

Hence the frequency of violent and criminal acts committed by the insane, and the well-known axiom in psychiatry according to which all subjects of hallucinations are dangerous patients. Revington has found, from a study of forty-nine cases of homicide committed by insane patients, that in most instances the murder resulted from a hallucination.1

The reactions caused by hallucinations are often abrupt, unreasonable, and of an impulsive character, especially in the feeble-minded and in patients with profound clouding of consciousness (delirium tremens, epileptic delirium). But they may also show all the evidences of careful premeditation. Certain persecuted patients, exasperated by their painful hallucinations, prepare their vengeance with infinite precaution.

The influence of hallucinations upon the will is often so powerful that nothing can combat it, neither the sense of duty, nor the love of family, nor even the instinct of self-preservation. A patient passing near a river heard a voice tell him: "Throw yourself into the water." He obeyed without hesitation, and to justify himself declared simply: "They told me to do it; I was forced to obey."

Combined hallucinations. Sometimes hallucinations affect but one sense. Such are the hallucinations of hearing at the beginning of systematized delusional states. Generally, however, the pathological disorder affects several senses, the different hallucinations either

1 Revington. Mental Conditions Resulting in Homicide. The Journ. of Ment. Sc., April, 1902.

following one another, or existing together without any correlation, or combining themselves and producing complex scenes either of a fantastic aspect or analogous to real life. In the latter case they bear the name of combined hallucinations. The patient sees imaginary persons, hears them speak, feels the blows that they inflict upon him, makes efforts to reject the poisonous substances which they force into his mouth, etc. This state, closely related to dreams, is always accompanied with marked clouding of the intellect.

Diagnosis of hallucinations.—Two possibilities may present themselves: (1) the patient directly informs the physician about his condition; (2) he gives no information whatever, either because of his reticence or because of his intellectual obtuseness.

In the first case the diagnosis of hallucinations is generally easy. It is necessary, however, to ascertain that the pathological phenomenon is really a hallucination, and not an illusion; in other words, that it is a perception without an object, and not an inaccurate perception. Only a detailed examination of the circumstances under which the phenomenon shows itself may prevent an error; it is very difficult indeed when a subject hears himself being called a thief in the midst of thousands of street noises, to decide whether he experiences a hallucination or an illusion. The certainty is, on the other hand, much greater when the morbid perception occurs in absolute silence, as during the night, for instance.

In the second case the diagnosis must be made without the assistance of the patient, or even in spite of his denials. It must be based only upon the patient's attitudes, movements, and at times upon the means of