A LUNATIC, or _non compos mentis_, is one who hath had understanding, but by disease, grief, or other accident hath lost the use of his reason. A lunatic is indeed properly one that hath lucid intervals; sometimes enjoying his senses, and sometimes not, and that frequently depending upon the change of the moon. But under the general name of _non compos mentis_ (which sir Edward Coke says is the most legal name[r]) are comprized not only lunatics, but persons under frenzies; or who lose their intellects by disease; those that _grow_ deaf, dumb, and blind, not being _born_ so; or such, in short, as are by any means rendered incapable of conducting their own affairs. To these also, as well as idiots, the king is guardian, but to a very different purpose. For the law always imagines, that these accidental misfortunes may be removed; and therefore only constitutes the crown a trustee for the unfortunate persons, to protect their property, and to account to them for all profits received, if they recover, or after their decease to their representatives. And therefore it is declared by the statute 17 Edw. II. c. 10. that the king shall provide for the custody and sustentation of lunatics, and preserve their lands and the profits of them, for their use, when they come to their right mind: and the king shall take nothing to his own use; and if the parties die in such estate, the residue shall be distributed for their souls by the advice of the ordinary, and of course (by the subsequent amendments of the law of administrations) shall now go to their executors or administrators. [Footnote r: 1 Inst. 246.] THE method of proving a person _non compos_ is very similar to that of proving him an idiot. The lord chancellor, to whom, by special authority from the king, the custody of idiots and lunatics is intrusted[s], upon petition or information, grants a commission in nature of the writ _de idiota inquirendo_, to enquire into the party's state of mind; and if he be found _non compos_, he usually commits the care of his person, with a suitable allowance for his maintenance, to some friend, who is then called his committee. However, to prevent sinister practices, the next heir is never permitted to be this committee of the person; because it is his interest that the party should die. But, it hath been said, there lies not the same objection against his next of kin, provided he be not his heir; for it is his interest to preserve the lunatic's life, in order to increase the personal estate by savings, which he or his family may hereafter be entitled to enjoy[t]. The heir is generally made the manager or committee of the estate, it being clearly his interest by good management to keep it in condition; accountable however to the court of chancery, and to the _non compos_ himself, if he recovers; or otherwise, to his administrators. [Footnote s: 3 P. Wms. 108.] [Footnote t: 2 P. Wms. 638.]