All organic cerebral affections, whether diffuse or localized, have an influence upon the psychic functions.

The most important among those which have not already been considered are tumors, multiple sclerosis, brain abscess, and central neuritis.

Tumors, when small and of slow growth, may give rise to no mental symptoms. In other cases the mental state presents certain peculiarities which may aid in the diagnosis: Dupre and Devaux l have found that "patients suffering from cerebral tumor present a peculiar state of mental depression and enfeeblement, which constitutes their dominant psychopathic note: this state is one of torpor, 'psychic dullness, and clouding of the intellect, to which may be added mental puerilism." Properly speaking these cases present no true dementia until the affection has reached its terminal period. According to the same authors 2 "the intelligence, though clouded, is, however, not destroyed. It responds to strong stimuli, to imperious injunctions; it is veiled, but nevertheless present, and not until the last phases of the development of the affection does it decline and finally disappear."

1 Nouvelle iconographie de la Salpetriere. Tumeur cererrale, 1901, Nos. 2 and 3, p. 51.

2 Loc. cit., p. 8.

The diagnosis of brain tumor is based chiefly on the neurological symptoms; these are usually classified into cardinal symptoms, common to all tumors and resulting from increase of intracranial pressure - severe and persistent headache, slow pulse, vertigo, vomiting, and gradual impairment of vision due to optic neuritis - and focal symptoms, varying with the location of the tumor - Jacksonian epilepsy, monoplegia, hemiplegia, aphasia, apraxia, hemianopsia, oculo-motor paralysis, etc.

The differentiation between brain tumor and general paralysis may present considerable difficulty, the more so in view of the fact that in the case of tumors involving the meninges the cerebro-spinal fluid, as in general paralysis, may show an increase of cellular elements. The application of the Wassermann reaction may aid materially in the diagnosis.

Multiple sclerosis may be accompanied by a gradually progressive mental deterioration simulating that of general paralysis. In such cases too the application of the Wassermann reaction may aid in the diagnosis.

Brain abscess occurs chiefly as a complication of chronic purulent otitis media. The symptoms are slow pulse, localized headache, fever of the asthenic type, often subnormal temperature; mentally there are dullness, confusion, restlessness, and in severe cases coma. The abscess is generally located either in the temporal lobe - when amnesic aphasia is a prominent symptom if the lesion is on the left side - or in one cerebellar hemisphere - causing vomiting, vertigo, and staggering gait. The diagnosis rests upon a history of chronic otitis media, the symptoms here enumerated, and a microscopical examination of the blood which generally reveals leucocytosis; an exploratory operation may be necessary and should be done early in every case in which this condition is suspected.

Central Neuritis

Cases of this highly interesting though rather rare condition have been reported by Wiglesworth,1 Meyer,2 Worcester,3 Turner,4 Cotton and Southard,5 Somers and Lambert,6 and others. The first systematic clinical and anatomical study was made by Meyer.7

Although clinically this condition is not very well defined and varies a good deal in its aspect, the anatomical changes found post mortem are highly characteristic and constitute the basis of its autonomy.

These changes are revealed only on microscopic examination and consist in widespread parenchymatous degeneration of the central nervous system unaccompanied by any inflammatory reaction. Large nerve cells, especially those in the motor area of the cortex in both cerebral hemispheres, present the so-called axonal alteration: the cell body is somewhat swollen; the stainable substance, especially in the central part of the cell, is converted into a diffusely staining, structureless, or into a finely powdered, mass; the nucleus is pushed toward the periphery of the cell and may be slightly flattened or distorted. Marchi preparations reveal corresponding degeneration of fiber tracts, particularly those connected with the motor cortical areas.

The nature of central neuritis is not understood, and but little is known of its etiology. Most cases that have been reported occurred in institution practice either as terminal episodes in some chronic psychoses or in connection with acute mental confusion. It affects both sexes, chiefly in the fifth and sixth decades of life or thereabouts. In most of the cases no exciting cause is assigned; in a considerable number the trouble is said to have followed an attack of influenza, and in three cases it followed slight surgical operations done under general anaesthesia.

1 J. Wiglesworth. On the Pathology of Certain Cases of Melancholia Atlonita, or Acute Dementia. Journ. of Ment. Sc, Oct., 1883.

2 Adolf Meyer. Demonstrations of Various Types of Changes in the Giant Cells of the Paracentral Lobules. Amer. Journ. of Ins., Oct., 1897.

3 W. L. Worcester. A Case of Landry's Paralysis. Journ. of Nerv. and Ment. Dis., 1897.

4 John Turner. Note on a Form of Dementia Associated with a Definite Change in the Appearance of the Pyramidal and Giant-Cells of the Brain. Brain, 1899.

5 H. A. Cotton and E. E. Southard. A Case of Central Neuritis with Autopsy. Trans, of the Amer. Med.-Psychol. Assn., 1908.

6 E. M. Somers and C. I. Lambert. Central Neuritis. State Hosp. Bulletin, December, 1908.

7 Adolf Meyer. On Parenchymatous Systemic Degenerations Mainly in the Central Nervous System. Brain, 1901.

Normal Betz Cell

Fig. 5. - Normal Betz Cell. (After Adolf Meyer.)

Cell from a Case of Central Neuritis, showing Axonal Alteration

Fig. 6. - Cell from a Case of Central Neuritis, showing Axonal Alteration. (After Adolf Meyer.)

Singer and Pollock l found the lesions of central neuritis in a series of twelve cases of pellagra dying during the acute or subsiding stages of the pellagrous attack. "Seven of them died at a short interval after the skin lesions had subsided, with clinical symptoms of central neuritis. In the other five there were no symptoms, such as evidence of pyramidal tract lesion (Babinski reflex, jactatoid spasms, etc.), to suggest central neuritis, although diarrhoea with rapid and progressive emaciation and weakness were almost always present." This, of course, suggests the possibility of an essential connection between central neuritis and pellagra which had been previously overlooked.

The mental symptoms, given in the order of their frequency, are: depression with anxiety or sudden apprehen-siveness; restlessness and agitation; perplexity, confusion; hypochondriacal or persecutory delusions, often of an extremely absurd character; hallucinations. Refusal of food has occurred in more than half of the cases, and suicidal tendency is almost as common.

Among the physical symptoms the most striking are: stumbling, falling, unsteady gait; peculiar seizures - faint-ness, violent shaking, rigidity; muscular twitchings, irregular jerky movements, jactations; maladjustment in all movements; the knee-jerks are most frequently exaggerated, but in some cases they are diminished or even absent; the speech is apt to become very indistinct; toward the last, dysphagia; in some cases there is little or no reaction to pin-pricks. The general constitutional disturbance is grave: there is usually emaciation which may be extreme; diarrhoea has been observed in nearly three-fourths of the cases; a slight, irregular febrile reaction appears, the patient becomes exhausted, falls into stupor, and dies; in some cases death follows a sudden turn for the worse or actual collapse.

1 Singer and Pollock. The Histopathology of the Nervous System in Pellagra. Archives of Internal Medicine, June, 1913.