Of psychical and psycho-sensorial hallucinations - The interposition of the senses - Intellectual and sensorial phenomena of hallucinations of sight and hearing - Statistics - Double-sighted hallucination - Phenomena of hallucinations of smell, taste, touch, and general sensitiveness - Manner of the associations of hallucinations - Periods favorable to the production of hallucinations - Hallucinations in dreams - Symptoms of illusions - Sexual hallucinations - Intellectual mechanism of hallucinations - Circumstances favorable to the production of hallucinations - Of the hallucinatory state - Recapitulation.

The habit of considering hallucination as an inseparable symptom of insanity, has hitherto diverted attention from the physiology of this curious phenomenon. The numerous facts which we have gathered, the works of our brethren, and above all those of M. Baillarger, enable us now to fill up the hiatus.

But, before entering on this examination, a preliminary question suggests itself: is hallucination psychical or psycho-sensorial? In other words, is it purely intellectual, or does it require the intervention of the senses?

Monsieur Baillarger, who has ably sustained this double nature of hallucinations says, that in lunatics, hallucinations appear rather as purely psychical, whilst, in sane persons, the action of sensorial organs must be acknowledged. Thus, he considers that there exist two kinds of false perception; the one complete, composed of the two elements which result from the double action of imagination and the organs of the senses; these are psycho-sen-sorial hallucinations; the others incomplete, resulting only from the involuntary exercise of memory and imagination; these are psychical hallucinations. Howsoever strong a partisan this physician may be for the intervention of the senses in psycho-sensorial hallucinations, he allows that the participation of the senses cannot be explained, but may, to a certain point, be proved. We subjoin the arguments on which his opinion is founded: -

Burdach says, in speaking of hallucinatory images, "We really see them; the eye has the same sensation as if an external object was placed before the living and open eye."*

Muller adds, having attentively watched his own case, "We are soon convinced that they are not simple ideas, but really sensations." "Those who have been cured of hallucinations," continues Monsieur Baillarger, say, "I saw, I heard, as distinctly as I see and hear you;" their hallucinations are to them actual sensations." †

Mr. Bayle has published a remarkable case in the Medical Review, of an hallucinated young lady, who believed herself surrounded by demons, which she saw, heard, and touched. We transcribe the replies she made to those who endeavored to point out her error: "How are objects understood? Because they are seen and touched. So I see, hear, and touch the demons who come out of me, and I most distinctly feel those which are within me. Why do you desire me to repudiate the testimony of my senses, to which all refer as the source of knowledge?" If arguments were sometimes advanced to her on the errors of the senses, which she could observe in other patients, she rebutted this comparison: "My eye sees," she would reply; " my ear hears, and my hand touches. The patients, of whom you speak, are deceived; one of their senses is contradicted by another. For myself, on the contrary, I have the evidence of all."

Gruthuisen, quoted by Burdach, reports cases which he witnessed, in which the sensorial organs retained, on awaking, the sensation of the impression of a dream; thus, having dreamed of the discharge of a gun, his ear still rang with the sound on awaking. ‡

M. Baillarger chiefly finds the most satisfactory details in support of his opinions in observations on false visual perceptions.

The English physiologist Bostock, whose curious hallucinations I have related, remarked that the images followed the direction of the eyes. Gruthuisen has seen cases in which these images concealed external objects. Amongst other facts, he relates that, agreeably to ordinary optical laws, a very brilliant fantastic image left in its place a figure similar in appearance, but dim and shadowy.

* Burdach, Traite de Physiologic, trad, par Jourdan, t. v. p. 206, Paris, 1830.

† Muller, Manuel do Physiologie, trad, par Jourdan, t. ii. p. 606, Paris, 1845.

‡ Op. cit. t. v. p. 202.

The decreasing progression in the brilliancy of images, and above all, the persistence of certain portions, should be recollected in demonstrating the action of the organs of the senses.

The case of the English doctor, M. H., which I have given, is, according to M. Baillarger, a most important one to prove that phenomena truly sensorial exist in hallucinated persons. Thus, when this physician turned around, after having gazed on a brilliant object, he continued to see it for a considerable time. Wishing to verify the experience of Dr. Brewster, on the distinction of real or fanciful objects, he pressed the globe of one of his eyes, and saw the figure before him double and of its natural size.*

The argument of M. Baillarger, which we give as faithfully as possible, does not carry conviction to our minds, and we do not find in it any proof which places beyond doubt the intervention of the senses in hallucination, and the production of the image in the eye. As to the motives alleged by Burdach and Muller, to prove that the perception is the same as that experienced by a clear and open eye, we reply, that a man whose leg has been amputated, complains, long afterwards, of a pain in his foot; the sensation is as real to him as if the member had not been removed.

We purposed making several important objections to this" theory; but the critical investigation to which M. de Chambre has subjected the question appearing to us to sum up the principal ones, we confine ourselves to a quotation.