motor inhibition gradually becomes less prominent and is replaced by excitement; flight of ideas and logorrhoea appear. Finally the sadness disappears and maniacal elation replaces it.

When a maniac falls into depression the same transition occurs inversely.

The treatment of each phase comprises the same indications as for attacks of simple depression and of mania respectively.

Attacks of manic depressive insanity present a very marked tendency to recur. According to the particular forms assumed by the successive attacks, several types of manic depressive insanity are distinguished.

(A) Periodic insanities:

(a) Recurrent mania;

(b) Recurrent melancholia. (B) Alternating insanity. (C) Insanity of double form. (D) Circular insanity.

(E) Irregular forms.

(A) Periodic insanities. - (a) Recurrent mania. - The attacks are always of the maniacal type and are separated from each other by normal periods. The number of attacks and the duration of the normal periods vary greatly. Some patients have but two or three attacks during their lifetime; it is altogether exceptional for an individual to have but one attack, at least if his life

is a long one. In all likelihood non-recurring mania does not exist.

In other cases the attacks follow each other at brief intervals and with a certain regularity.

(b) Recurrent melancholia. - Less frequent than the preceding, this form is, so to speak, its counterpart. What has been said about recurrent mania is applicable to recurrent depression.

SCHEME II. RECURRENT MELANCHOLIA

(B) Alternating insanity. - Attacks of mania and those of depression alternate and are separated from each other by normal intervals.

(C) Insanity of double form. Each attack consists of a period of depression and one of excitement; the attacks are separated from each other by normal intervals.

(D) Circular insanity. Attacks of double form follow each other without interruption.

(E) Irregular forms.-These are the most frequent. The attacks follow each other without order or regularity, assuming at random the depressed, manic, or mixed form.

Finally, one may observe the periodic, circular, and irregular forms combine in a very complex manner, so that, for instance, a patient with circular insanity becomes a periodic maniac for a time, or a patient whose previous attacks have all been of the manic type presents an attack of depression.

It is quite frequent, though not constant, to see attacks of the same type present each time the same aspect: a manic attack resembles previous ones in the same patient, and it is very probable that the future manic attacks will present the same features.

The general prognosis of the disease is not favorable. The attacks have in some cases a tendency to come closer together, so that the normal intervals become gradually shorter and shorter until they are either totally wanting or almost so.

Manic depressive insanity is a common disease. According to Kraepelin it represents about 15% of all asylum admissions.

The causes are not fully known; the essential feature in the etiology seems to be a constitutional

predisposition which is believed to be inherited. Kraepelin has found neuropathic heredity in 80% of his cases; the heredity is often similar.

The special predisposition to have attacks of manic depressive insanity seems to be observed with particular frequency in persons of certain fairly welldefined mental make-up; such make-up is characterized either by a sort of constitutional pessimism, gloomy or worrisome disposition, or, on the contrary, by a happy, exuberant, demonstrative temperament, or, finally, by emotional instability consisting of exaggerated reactions to situations by despair, discouragement, or by premature and unwarranted display of triumph and hopefulness, as the case may be. This was pointed out by Hoch1 who has emphasized particularly the contrast which such personalities present to that type of personality—the "shut-in personality" — which he has defined as being particularly prone to develop dementia præcox.2 In a more recent study Reiss has arrived at similar conclusions, as may be seen from the following quotation: "Upon a survey of the whole material which has been at my disposal, we find as a general fact that in cases of happy disposition manic states, while in those of pronounced depressive disposition the sad melancholy states predominate."

3

The age at which the first attack occurs is not con

1 Journ. of Nerv. and Ment. Dis., Apr., 1909.

2 See p. 284.

3 Eduard Reiss.

Konstitutionelle Verstimmung und manischdepressives Irresein. Zeitschr. f. die gesamte Neurol. u. Psychiatrie,

Vol. II, p. 600, 1910.

stant. In most cases it is before the twenty-fifth year, in some before the tenth, and in others after the fiftieth. Quite frequently in women the disease appears with the onset of menstruation or with the first pregnancy.

Diagnosis. The principal elements of diagnosis are: psychic paralysis associated with the special symptoms of exaltation of the mental automatism, which have already been described; absence of real intellectual enfeeblement; recurrency of the attacks with restitutio ad integrum after each.

We differentiate:

General paresis by the pathognomonic intellectual enfeeblement, a certain degree of which persists even during the remissions; and by the equally pathognomonic physical signs;

Involutional melancholia by the intense and persistent psychic pain, which is much more marked than in the depressed form of manic depressive insanity;

Acute confusional insanity by its special etiology, and by the much more marked disorientation;

Delirium tremens by its specific hallucinations; Dementia præcox by the rapid and pronounced diminution of affectivity, by the catatonic phenomena which are so frequent in such cases, and by the absence of flight of ideas even in those cases which closely resemble mania.

Homogeneity of manic depressive insanity. - Fundamental symptoms. The conception of manic depressive insanity is due to Kraepelin and constitutes one of the most important recent advances in