The same objection may be made to the suspension of external impressions; if in many cases it exists, in an equal number it is missing. We attend two ladies, who, with the exception of their hallucinations, are perfectly rational; the one hears voices which suggest evil thoughts; these voices continue their whisperings, notwithstanding needle-work, amusement, or conversation, in which she joins with pleasure. When questioned as to these voices, she replies: "My conviction in their existence is as strong as yours in your sensations." The other is a young lady who, in the midst of conversation or of her work, stops suddenly to gaze into the air. To any interrogations, she calmly replies: "I am looking at the snow which is falling from the ceiling," or, "the wall has just opened to let several men pass through." These visions do not at all prevent her taking part in all that passes in the parlor, or in making remarks on the conversation and works of other ladies. In neither of these cases is there any symptom of reverie or forgetfulness of the external world; nor does speaking to them suspend the hallucinations. The scholar, mentioned by M. Baillarger, appears to us a powerful example against the suspension of external impressions. We cannot then say that this is a general disposition of mind. If, however, the relaxation of attention be favorable to the production of hallucinations, how is it that when this faculty is strongly excited by the contemplation of the vision, it still continues, and even for a considerable time, although with a consciousness of its falsity, as the cases of Nicolai and Bostock evince?

A last condition necessary to the production of hallucination, consists in an excitation extended to one or several of the sensorial organs, at least in their intra-cerebral portions. As a proof in support of this, we may observe that persons in the habit of using a microscope, often see suddenly the object which they have been examining at intervals, for several hours after they have ceased their observations.

In bringing to a close that which relates to the physiology of hallucinations, we must draw attention to a disposition of mind to which the name of hallucinatory condition has been given, and which, independently of hallucinations, is characterized: 1st. By loss of consciousness of time, place, and surrounding objects; 2d. By an entirely involuntary exercise of memory and imagination. This is the aparte of Esquirol, which is likewise observed in the most rational men who are absorbed by some deep meditation.* The involuntary exercise of the faculties does not only accompany hallucinations, it often precedes them; forming, as it were, their precursor. The state of hallucination is of variable duration; it may last for several hours, or only for a few seconds.

Recapitulation. - The physiology of hallucinations offers great difficulties, for which reason they have been considered inseparable from insanity. Hallucination has been described by several authors as composed of two elements, psychical and sensorial; the fact appears unfavorable to the theory of the intervention of the senses. The sensorial action appealed to by Burdach and Muller, is no more real than is the cerebral pain belonging to a long amputated member. If sensation exists in the organ, how can hallucination of the blind and deaf be explained? If even the phenomenon passes solely in a certain portion of the brain, it cannot, for that reason, have any need of the sensorial organ.

But even if we reject the intervention of the senses, the division of hallucinations into psycho-sensorial and psychical is no less useful in the classification of the phenomena. The degree of intensity appears to us the best illustration of this classification.

This decomposition of the elements of hallucination naturally leads to the study of the intellectual and sensorial phenomena. Amongst the intellectual phenomena of hallucinations of hearing, the frequency of which places them in the foremost rank, we must range different kinds of noises, the repetition of some particular word or words, the reproduction of the habitual preoccupation of mind in the individual. Even when hallucinations present some extraordinary feature, they may be traced to reading, conversation, and recollections. There are, however, a certain number of visions which have no connection with occupations, thoughts, or habitual works.

* Dee Maladies Mentales, Paris, 1838.

Hallucinations may come from without; they are more frequently ascribed to invisible beings, who speak in the second or third person, or to indeterminate persons, as they, them. The number of interlocutors may be considerable.

An interesting phenomenon in reference to psychology, is that which excites a belief in the existence of two individuals, or two principles in the same person; the one inciting to evil, the other urging to good.

In general, hallucinations are not under the control of the will. Sometimes, however, they are so; which is a powerful argument against the relaxation of attention; they disappear or continue, notwithstanding a desire to the contrary. The most powerful concentration of thought cannot sometimes reproduce an hallucination which, a few moments previously, has appeared uncalled for.

When hallucinations of hearing are exhibited in several languages spoken by the person affected, the least distinct are those of the language with which he is the least familiar.

The intellectual faculties may receive a greater development in hallucinations; this symptom particularly has been already proved; it accounts for the extraordinary influence which certain men have exercised on their fellow-creatures, with the reservation, however, that these hallucinations are compatible with reason.

Intellectual hallucinations of hearing may be the reproduction of vivid anterior sensations.

The sensorial phenomena of hallucinations of hearing are characterized by sounds more or less solemn. They most usually resemble murmurings and whisperings. The sounds may suddenly cease and conversations take place mentally.