Lord Hale, who first pointed out the distinction to be drawn between total and partial insanity, offered the following as the best test he could suggest: “Such a person, as labouring under melancholy distempers, hath yet as great understanding as ordinarily a child of fourteen years hath, is such a person as can be guilty of felony.” (On this subject, see R. v. Ld. Ferrers, 19 St. Tr. 333; R. v. Arnold, 16 St. Tr. 764, &c.)
To excuse a man from punishment on the ground of insanity, it appears that it must be distinctly proved that he was not capable of distinguishing right from wrong, and that he did not know, at the time of committing the crime, that the offence was against the laws of God and nature (R. v. Offord, 5 C. & P. 186).
I shall here quote from Macdonald‘s Criminal Law of Scotland: “Insanity or idiocy exempts from prosecution. But there must be an alienation of reason such as misleads the judgment, so that the person does not know ‘the nature of the quality of the act’ he is doing, or if he does know it, that he does not know he is doing what is wrong. If there be this alienation, as connected with the act committed, he is not liable to punishment, though his conduct may be otherwise rational. For example, if he kill another when under an insane delusion as to the conduct and character of the person—e.g. believing that he is about to murder him, or is an evil spirit,—then it matters not that he has a general notion of right and wrong. For, in such a case, ‘as well might he be utterly ignorant of the quality of murder.’ He does the deed, knowing murder to be wrong, but his delusion makes him believe he is acting in self-defence, or against a spirit. Nor does it alter the effect of the fact of insanity at the time, that the person afterwards recovers.... But the alienation of reason must be substantial. Oddness or eccentricity, however marked, or even weakness of mind, will not avail as a defence. Even monomania may be insufficient as a defence, where the delusion and the crime committed have no connection, or where the person, though having delusions, was yet aware that what he did was illegal.”
Mere moral insanity—where the intellectual faculties are sound, and the person knows what he is doing, and that he is doing wrong, but has no control over himself, and acts under an uncontrollable impulse—does not render him irresponsible (R. v. Burton, 3 F. & F. 772). Some medical writers contend that there are two forms of insanity—moral and intellectual. The law only recognises the latter, owing probably to the difficulty of distinguishing between so-called moral insanity and moral depravity. Taylor says: “Further, until medical men can produce a clear and well-defined distinction between moral depravity and moral insanity, such a doctrine, employed as it has been for the exculpation of persons charged with crime, should be rejected as inadmissible.”
The day may not be far distant when the term “moral depravity” will be unknown, and future generations, ceasing to believe in absurd superstitions, will come to look on crime as the result of disease of the brain, and learn to treat, instead of to punish, the morally diseased. (For a full discussion of this subject the reader is referred to the works of Dr. Henry Maudsley.)
The fact of the sanity or insanity of the prisoner at the time the crime was committed is left to the jury to decide, guided by the previous and contemporaneous acts of the party; and it has been laid down by Lord Moncreiff in Scotland, and Lord Westbury in England, that the mental soundness or unsoundness of any individual is to be decided by the jury on the ordinary rules of every-day life, and that on these principles they are as good judges as medical men. The whole tendency of legal practice, when dealing with the plea of insanity, is to entirely ignore the medical evidence. On the question of medical evidence in cases of insanity, Doe J., of New Hampshire, remarks: “At present, precedents require the jury to be instructed by experts in new medical theories, and by judges in old medical theories,” and that in this “the legal profession were invading the province of medicine, and attempting to install old exploded medical theories in the place of facts established in the progress of scientific knowledge. If the tests of insanity are matters of law, the practice of allowing experts to testify what they are should be discontinued; if they are matters of fact, the judge should no longer testify without being sworn as a witness, and showing himself qualified to testify as an expert.”
Lunacy—What Constitutes? (8 and 9 Vict. c. 100, secs. 90 and 114).—Imbecility and loss of mental power, whether arising from natural decay, or from paralysis, softening of the brain, or other natural cause, and although unaccompanied with frenzy or delusion of any kind, constitute unsoundness of mind, amounting to lunacy within the meaning of 8 and 9 Vict. c. 100 (R. v. Shaw, 1 C.C. 145).
The above is the last definition of lunacy up to 1875; but as the law on this subject is so constantly changing, the student will find it best to consult the Law Reports from time to time. (See the account in the case of R. v. Treadaway, Law Reports. Also the Lancet, on the same case, vol. i. 1877.)
For some valuable remarks on the subject of the irresponsibility of madmen, the student is referred to the works of Maudsley, Pritchard, Ray, Hoffbauer, Georget, and others.
The following suggestions are offered for consideration on this subject: