INSANITY. In Medical Jurispru dence. The prolonged departure, without any adequate cause, from the states of feel ing and modes of thinking usual to the indi vidual in health.
2. Of late years this word has been need to de signate all mental impairments and deficiencies formerly embraced in the terms lunacy, idiocy, and unsoundness of mind. Even to the middle of the last century the law recognized only two classes of persona requiring its protection on the score of mental disorder, viz.: lunatics and idiots. The former were supposed to embrace all who had lost the reason which they once possessed, and their disorder was called dementia accident° lie ; the lat ter, those who had never possessed any reason, and this deficiency was called dementia noturalie. Lu natics were supposed to be much influenced by the moon ; and another prevalent notion respecting them was that in a very large proportion there oc curred lucid intervals, when reason shone out, for a while, from behind the cloud that obscured it, with its natural brightness. It may be remarked, in passiog, that lucid intervals are far lees common than they were once supposed to be, and that the restoration is not so complete as the descriptions of the older writers would lead us to infer. In modern practice, the term lucid interval signifies merely a remission of the disease, an abatement of the vio lence of the morbid action, a period of comparative calm ; and the proof of its occurrence is generally drawn from the character of the act in question. It is hardly necessary to say that this is en unjustifi able use of the term, which should be confined to the genuine lucid interval that does occasionally occur.
It began to be found at last that a large class of persons required the protection of the law, who were not idiots, because they had reason once, nor luna tics in the ordivary signification of the term, be cause they were not violent, exhibited no very notable derangement of reason, were independent of lunar influences, and had no lucid intervals. Their mental impairment consisted in a loss of in tellectual power, of interest in their usuP1 pursuits, of the ability to comprehend their relations to persons and things. A new term—unsoundness of mind—was, therefore, introduced to meet this exi. gency; but it has never been very clearly defined.
3. The law has never held that ad lunatics and idiots are absolved from all responsibility for their civil or criminal acts. This consequence was attri buted only to the severest grades of these affections, —to lunatics who have no more understanding than a brute, and to idiots who cannot number twenty pence nor tell how old they are. Theoretically the law has changed hut little, even to the present day; but practically it exhibits considerable improve ment: that is, while the general doctrine remains unchanged, it is qualified, in one way or another, by the courts, eo as to produce lees practical in justice.
Insanity implies the presence of disease or con genital defect in the brain, and though it may be accompanied by disease in other organs, yet the cerebral affection is always supposed to be primary and predominant. It is to be borne in mind, how ever, that bodily diseases may be accompanied, in some stage of their progress, by mental disorder which may affect the legal relations of the patient.
4. To give a definition of insanity not congeni tal, or, in other words, to indicate its essential ele ment, the present state of our knowledge does not permit. Most of the attempts to define insanity are sententious descriptions of the disease, rather than proper definitions. For all practical purposes, however, a definition is unnecessary, because the r.•al question at issue always ie, not what consti tutes insanity in general, but wherein consists the insanity of this or that individual. Neither sanity nor insanity can be regarded as an entity to be handled and described, but rather as a condition to be considered in reference to other conditions. Men vary in the character of their mental manifestations, insomuch that conduct and conversation perfectly proper and natural in one might in another, differ ently constituted, be Indicative of insanity. In determining, therefore, the mental condition of a person, he must not be judged by any arbitrary standard of sanity or insanity, nor compared with other persons unquestionably sane or insane. He can properly be compared only with himself. When a person, without any adequate canse, adopts no tions he once regarded as absurd, or indulges in conduct opposed to all his former habits and prin ciples, or changes completely his ordinary temper, maim rs, and dispositions,—the man of plain prac tical sense indulging in speculative theories and projects, the miser becoming a spendthrift and the spendthrift a miser, the staid, quiet, unobtru sive citizen becoming noisy, restless, and boister ous, the gay and joyous becomieg dull and dis consdato even to the verge of despair, the care ful. cat.tious man of business plunging into hazard ous schemes of speculation, the discreet and pious becoming shamefully reckless and profligate,—no stronger proof of insanity can he had. And yet not one of these traits, in and by itself alone, dis connected from the natural traits of character, could he regarded as conclusive proof of insanity. In accordance with this fact, the principle has been laid down, with the sanction of the highest legal and medical authority, that it is the pro longed departure, without any adequate cause, from the states of feeling and modes of thinking usual to the individual when in health. which is the essential feature of insanity. Gooch, Lund. Quart. Rev. xliii. 335; Combe, Ment. Derang. 196; Meidway vs. Croft, 3 Curt. Reel. 671.