In the case of Stevens v. The State of Indiana, the instruction to the jury, that, if they believed the defendant knew the difference between right and wrong in respect to the act in question, if he was conscious that such act was one which he ought not to do, he was responsible—was held to be erroneous.
It would appear, then, that the American courts, which, having inherited the common law of England, at first followed docilely in the wake of the English courts, are now exhibiting a disposition to emancipate themselves from an authority which they perceive to be founded on defective and erroneous views of insanity, and a desire to bring the law more into accordance with the results of scientific observation. The decisions of the court of New Hampshire in Boardman v. Woodman, State v. Jones, and State v. Pike, are especially worthy of attention for their searching discussion of the relations of insanity to jurisprudence, and for the decisive abandonment of the right-and-wrong test of responsibility. In the case of State v. Pike, Chief-Justice Perley instructed the jury that they should return a verdict of not guilty "if the killing was the offspring of mental disease in the defendant; that neither delusion nor knowledge of right and wrong, nor design or cunning in planning and executing the killing, and in escaping or avoiding detection, nor ability to recognize acquaintance, or to labor or transact business or manage affairs, is, as a matter of law. a test of mental disease; but that all symptoms and all tests of mental disease are purely matters of fact to be determined by the jury."
"A striking and conspicuous want of success," said Judge Doe in the same case, "has attended the efforts made to adjust the legal relations of mental disease.... It was for a long time supposed that men, however insane, if they knew an act to he wrong, could refrain from doing it. But whether that suspicion is correct or not is a pure question of fact; in other words, a medical supposition—in other words, a medical theory. Whether it originated in the medical or any other profession, or in the general notions of mankind, is immaterial. It is as medical in its nature as the opposite theory. The knowledge-test in all its forms, and the delusion-test, are medical theories introduced in immature stages of science, in the dim light of earlier times, and subsequently, upon more extensive observations and more critical examinations, repudiated by the medical profession. But legal tribunals have claimed these tests as immutable principles of law, and have fancied they were abundantly vindicated by a sweeping denunciation of medical theories—unconscious that this aggressive defense was an irresistible assault on their own position.... In this manner, opinions, purely medical and pathological in their character, relating entirely to questions of fact, and full of errors, as medical experts now testify, passed into books of law, and acquired the force of judicial decisions. Defective medical theories usurped the position of common-law principles.... Whether the old or the new medical theories are correct is a question of fact for the jury; it is not the business of the court to know whether any of them are correct. The law does not change with every advance of science; nor does it maintain a fantastic consistency by adhering to medical mistakes which science has corrected. The legal principle, however much it may formerly have been obscured by patho-
