a defect of understanding. Both idiocy and lunacy excuse from the guilt of crimes. For the rule of law as to lunatics, which may also be easily adapted to idiots, is, that furiosus furore solum punitur. In criminal cases, therefore, idiots and lunatics are not chargeable for their own acts, if committed when under these incapacities; not even for treason itself. Also, if a man in his sound memory commits a capital offence, and before arraignment becomes mad, he ought not to be arraigned for it; because he is not able to plead to the charge with that advice and caution that he ought. And if, after he has pleaded, the prisoner becomes mad, he shall not be tried; for how can he make his defence? If, after he be tried and found guilty, he loses his senses before judgment, judgment shall not be pronounced; and if, after judgment, he becomes of unsound memory, execution shall be stayed; for peradventure, says the humanity of the English law, had the prisoner been of sound memory, he might have alleged something in stay of judgment or execution. But if there be any doubt whether the party be compos or not, this shall be tried by a jury; and if he be found non compos, a total idiocy, or absolute insanity, excuses from the guilt, and of course from the punishment, of any criminal action committed under such deprivation of the senses; but if a lunatic has lucid intervals of understanding, he shall answer for what he does in those intervals, as if he had no deficiency. It was the doctrine of the ancient English law, that persons deprived of their reason might be confined till they recovered their senses, without waiting for the forms of a commission or other special authority from the crown; but now a method is chalked out for imprisoning and sending them to their proper homes.

The matrimonial contract, likewise, cannot take place in a state of idiocy. It was formerly adjudged, that the issue of an idiot was legitimate, and his marriage valid. But since consent is absolutely requisite to matrimony, and neither idiots nor lunatics are capable of consenting to any thing, therefore the civil law judged much more sensibly when it made such deprivations of reason a previous impediment, though not a cause of divorce if they happened after marriage. Modern resolutions have adhered to the sense of the civil law, by determining that the marriage of a lunatic, not being in a lucid interval, was absolutely void. But as it might be difficult to prove the exact state of the party's mind at the actual celebration of the nuptials, the statute 15 Geo. II. c. 30, has provided, that the marriage of lunatics and persons under phrenises (if found lunatics under a commission, or committed to the care of trustees under any act of parliament), before they are declared of sound mind by the lord chancellor, or the majority of such trustees, shall be totally void.

Idiots and persons of unsound memory, as well as infants and persons under duress, are not totally disabled either to convey or purchase, but sub modo only; for their conveyances and purchases are voidable, but not actually void. The king, indeed, on behalf of an idiot, may avoid his grants or other acts. But it has been said, that a non compos himself, though he be afterwards brought to a right mind, shall not be permitted to allege his own insanity in order to avoid such grant; because no man shall be allowed to stultify himself, or plead his own disability. The maxim that a man shall not stultify himself, has in fact been handed down as settled law; though later opinions, feeling the inconvenience of the rule, have in many points endeavoured to restrain it. The next heir, or other person interested, may clearly, after the death of the idiot or non compos, take advantage of his incapacity, and avoid the grant; and so, too, if he purchases under this disability, and does not afterwards upon recovering his senses agree to the purchase, his heir may either waive or accept the estate at his option. In like manner, an infant may waive such purchase or conveyance when he comes to full age; or, if he does not then actually agree to it, his heir may waive it after him. By the statute 11 Geo. III. c. 20, the guardians or committees of a lunatic are empowered to renew in his right, under the directions of the Court of Chancery, any lease for lives or years, and apply the profits of such renewal for the benefit of such lunatic, his heirs, or executors.

In the law of Scotland, an idiot, or fatuous person, is one entirely deprived of the faculty of reason, having an uniform stupidity and inattention in his manner, and a childishness in his speech, which distinguish him from other men. This state is ascertained by the judgment of a jury, on a brief directed to the judge-ordinary of the bounds within which the person resides, and containing two heads of inquest; one relating to the state of the person, and the other having for its object to ascertain who is the nearest male agnate of twenty-five years of age. The briefs for cognoscence of persons are nearly similar, differing only in the description of the circumstances into which the jury are to inquire. As a state of idiocy disqualifies the person for entering into transactions, a proof, even after his death, that the grantor of a deed was an idiot at the time of granting it will be sufficient for reducing that deed; and, according to Bankton, restitution on the ground of idiocy is competent to idiots against their curators within four years after their convalescence, in the same way as it is competent to minors.