Under this heading may be included idiocy, cretinism, imbecility, feeble-mindedness, and moral imbecility.
Idiocy is congenital, and was defined by Esquirol thus: Idiocy is not a disease, but a condition in which the intellectual faculties are never manifested, or have never been developed sufficiently to enable the idiot to acquire such an amount of knowledge as persons of his own age, and placed in similar circumstances with himself, are capable of receiving. Idiocy commences with life, or at an age which precedes the development of the intellectual and affective faculties, which are from the first what they are doomed to be during the whole period of existence. Since the days of Esquirol, much improvement has been made in the care and treatment of the idiot; and it appears that he is capable of some, though in most cases slight, mental culture. The cases in which improvement takes place probably belong to imbecility, leaving the idiot in the same condition as described by Esquirol.
Cretinism differs from idiocy in being endemic; it is also more curable, or at least more susceptible of improvement, than the latter. In the idiot the malady is congenital; the cretin, on the other hand, may to all appearances be free from disease for a time. “Every cretin is an idiot, but every idiot is not a cretin; idiocy is the more comprehensive term, cretinism is a special kind of it.” The enlarged thyroid gland, high-arched palate, and brown or yellow colour of the skin, are characteristic of the cretin. Local causes are at work in the production of cretinism; e.g. defective function of the thyroid gland.
The idiot is usually cunning, mischievous, and dirty in his habits.
The derivation of the word idiot, from the Greek, ίδιώτης— a private person, or an ill-informed ordinary fellow—is peculiar. A person suffering from any form of mental unsoundness, and thereby rendered incapable of taking care of himself or of his property, was formerly called by English law “an idiot,” and this word was not infrequently joined with “fatuus” in old writs.
Imbecility.—This is a minor form of idiocy, and may or may not be congenital. It admits of considerable degrees of intensity. Imbeciles exhibit mental defection, rendering them incapable of managing themselves or their affairs, and imbecile children are incapable of being taught to do so.
Feeble-mindedness is a lesser degree of mental defection than imbecility. It may exist from birth or an early age. Such persons require care and control for the protection of themselves and others. They may be incapacitated from acquiring the knowledge imparted in ordinary schools.
Moral imbeciles exhibit moral defects which render them vicious in behaviour, and they often exhibit criminal tendencies, which are not affected by punishment.
CARE OF MENTALLY DEFECTIVE PERSONS
The Mental Deficiency Act of 1913 provides for their care. Such a person may be either sent to an institution or placed under special guardianship by the parent or guardian, if an idiot or imbecile; or by the parent when, though not an idiot or imbecile, the person affected be under the age of twenty-one years. If in addition to being a defective, the person is neglected, abandoned, or without means of support; or cruelly treated, guilty of a criminal offence, or liable to be sent to an industrial school, or under imprisonment, detained in an industrial school, inebriate reformatory, or institution for lunatics, or habitual drunkard within the meaning of the Inebriates Act; or in whose case proper notice has been given by the Local Education Authority; or who is in receipt of relief at the time of giving birth to an illegitimate child, or pregnant of such child.