"We have never been able to discover clearly, notwithstanding the great authority of Muller and Burdach, the alleged intervention of the senses in hallucinations. According to the former, visions are actually conditions of the sense of sight, and according to the latter, we then perceive in the eye, when the thought occurs, the same sensation as if an external object was placed before the open eye. Experimentally, if it be thus, if the organ of sense be a function, and sensation exists in the or-gan, it necessarily follows that hallucination would be impossible if that organ were destroyed. Thus the blind would have no visions, the deaf would hear no voices. Now, we know that the contrary is often the case. The reply to this objection is, that if the organ itself be incapable of sensation, that part of the brain to which the sensation belongs is the seat of the phenomenon. But what does this mean? Has the brain one dwelling for the sensation of sight, another for the sensation of hearing, a third for that of taste? And even if it had, how will it affect those who deny the intervention of the senses in hallucination? If this phenomenon occurs solely in one part of the brain, it has nothing to do with the sensorial organ of the eye or the ear, and that is ail they maintain. Beyond these terms, lies nothing but darkness. Theoretically, the intervention of the senses, as it is here understood, appears to us useless or impossible. One or other of these two things must be said: either a false sensation formed in the eye, is conveyed to the brain, or the brain, by the action of a false thought, creates a sensation on the eye. Now, an image cannot be formed in the eye without an external object; for an image existing only in the sensorial organ, and before the intervention of the brain, is not and cannot be anything but a certain arrangement of luminous rays. So much for the first sense. In regard to the second, may not the unregulated exercise of thought be, as Burdach asserts, the occasion of a false sensation in the eye? It will be conceded that the idea is far from being lucid. How can a cerebral or a psychical conception engender the sensation of an image in the eye? In any case, of what use is this hypothesis? Is not a delirious conception wrought in the brain? When, for instance, it has imagined a legion of devils in action, the phenomenon is complete. Why say that it cannot occur without the intervention of the eye? If the devils really exist, it is not the eye, but the brain that sees them. In hallucination, the brain imagines, creates, and perfects them, and that is precisely the fundamental character of the phenomenon. All this does not prevent a distinction between intellectual hallucinations and those which are characterized by a sensible sign, a phenomenon of the sensorial order, and, in this respect, the works of some moderns, MM. Baillarger and Michea in particular, have been of essential service. It is true that certain hallucinated persons, like certain mystics, hear what they call internal voices, a sort of inarticulated words, a mute communication, audible only in the mind; that others, on the contrary, very distinctly hear voices who call them, and reply to them, and with whom they hold long conversations. Let them give to the first kind of hallucination the name of psychical, and to the second that of psycho-sensorial, nothing can be better. Let them strictly uphold that both the one and the other are engendered in the different portions of the brain, some physiologists may agree to this. But they are nowise authorized to admit, in the last, the intervention of the senses."*

* Baillarger, Des Hallucinations, des Causes qui les produisent, et des Maladies qu'elles caracterisent (in the Memoires de l'Academie Royale do Medecine, t. 12, p. 369).

But whilst rejecting the intervention of the senses, M. de Chambre no less recognizes their division into psycho-sensorial and psychical, as useful to assist in the study of hallucinations. We also think the distinction good, and adopt it, with the remark that we consider it applies only to the greater or less intensity of the phenomenon. If the perception be weak, the hallucination is noiseless - if more powerful, a sound is perceptible. We have ourselves noticed these mental conversations without the emission of any sound; but these conversations would be impossible if the word spoken had not accompanied the word thought; that is, if the conventional sign had not been attached to the idea. If, therefore, we do not admit the intervention of the senses in the production of hallucinations, we are no less convinced that the two constituent elements of hupnan nature are found in the hallucinatory reminiscence, and, in this point of view, we have also adopted the division of the phenomena of hallucinations into intellectual and sensorial.

In studying the hallucinations of sane persons, it is allowed, as we have already remarked, that those of sight are the most common, whilst, in the insane, those of hearing are the most frequent and most complex. According to Marc, hallucinations of hearing occur in at least two-thirds of the patients. Amongst the most simple and the least intellectual hallucinations of hearing, M. Baillarger ranks those of lunatics who hear different kinds of noises, such as the ringing of bells, firing of guns, etc. Then follow those which consist in the repetition of the same words. This phenomenon is equally noticed in persons in a healthy condition; thus, the pronouncing of a name, or even a word, obstinately dwells in the mind, harasses it awhile, and suddenly disappears.

* A. De Chambre, Analyse de l'ouvrage du Docteur Staf kowski sur les Hallucinations, Gazette Medicale, 1850, p. 274.

Hallucinations in a higher degree reproduce, like an echo, the habitual preoccupation of the patients, their ideas, their studies, and their words.

We may here notice the analogy of a mental habit with sound reason, in which many persons detect themselves talking to and replying to themselves. This bias of the mind often occasions a curious phenomenon. A man who reads a book or corrects a proof, full of the thought which engrosses him, reads it according to the text, although there is no similitude between the words written and the words thought.