TRANSITORY INSANITY is used by Krafft-Ebing[19] (Transitorisches Irresein) as indicating mental disease differing from other insanity only in the fact that it is of short duration—namely, from two to six days. If it is applied to sudden and transient outbursts of mania, with delirium, loss of power of self-control, and inability to clearly recollect the circumstances of the attack and what happened during its continuance, it is a rare disease, occurring for the most part in epileptics and in persons under the influence of alcohol or addicted to its habitual use. It is sometimes, under the latter-named condition, called alcoholic trance. It consists in an automatic state resembling the epileptic delirium, which may occur also in sleep and resemble somnambulism. The actions are guided by co-ordinated will without conscious intelligence, and may consist in crimes and brutalities and foolishness entirely inconsistent with the character in health. It seldom lasts more than a few hours. When caused by alcohol or as a symptom of epilepsy, it may occur without other marked inciting cause; otherwise it is commonly due to mental shock. Several cases happened during the mental excitement of the first battle in our civil war. The most striking case within my own experience was that of a man who under the strain of prolonged grief and the mental shock of a great fire destroying a large part of the town in which he lived, perhaps moderately affected by alcohol, suddenly grasped an axe and cut off with one blow the head of a beloved child. He was found in the street without knowing how he had got there or what he had done. [Footnote 19: _Irrenfreund_, 1883, p. 113.] One attack is the rule, although several, probably of an epileptic nature, have been reported. It is an extremely difficult condition to diagnosticate with certainty, and is therefore often the refuge of criminals and a resource of criminal lawyers. The most likely honest mistake liable to be made regarding it is to confound it with an outburst of passion. PRIMARY DEMENTIA (Acute dementia, Stuporous insanity, Anergic stupor) is a disease chiefly of youth and early maturity in persons of inherited weakness or under the influence of prolonged exhausting conditions, to which some mental shock usually adds the immediate cause. Although most of the cases are under the age of twenty-five, it occurs up to forty-five. Masturbation is so common a symptom in its course—and it may be one of the debilitating and enervating factors constituting a predisposing cause—that most of the primary dementia is classed in some asylums as insanity of masturbation. There may be an initial stage of a number of days, marked by moderate melancholia or by maniacal excitement, but there is usually mental torpor advancing rapidly to pronounced dementia. In rare cases there is marked chorea, and slight choreic movements are often observed. The course of primary dementia may be subacute and advance with extreme slowness.