be permitted to give mere opinions, disconnected from the facts on which such opinions are based" 1 Whart. C. L. (7th ed.), § 45. See also Hardy v. Merrill, supra; Com. v. Sturtevant, 117 Mass. 122; 19 Am. Rep. 401.

As a general rule, non-experts are confined to a mere statement of facts: Com. v. Wilson, 1 Gray (Mass.), 337; Caleb v. State, 39 Miss. 722; Gehrke v. State, 13 Tex. 568; Clapp v. Fullerton, 34 N. Y. 190; Real v. People, 42 N. Y. 270. And they cannot give an opinion upon a hypothetical statement of facts: State v. Klinger, 46 Mo. 228; Farrell v. Brennan, 32 Mo. 328; Boardman v. Woodman, 47 N. H. 120; Dunham's Appeal, 27 Cow. 192; Weems v. Weems, 19 Md. 334; Eckert v. Flowry, 43 Pa. St. 49.

Medical men who are possessed of medical skill are allowed to testify as experts and to give opinions as to the sanity or insanity of a person, either from personal examination of him or based upon a hypothetical case. So those who are not medical men are permitted to testify and give their opinion under certain circumthe manner of conducting the

stances

examination, and the facts from whence the witnesses draw their inferences or conclusions, are essentially different. The medical expert gives to the jury the result of his professional skill, science and learning. His opinions are brought to their assistance, but they are not conclusive upon the jury, and they may give them such weight as they deem they are entitled to, and no more. If the expert has been present in court, and has heard all the evidence, and there is no dispute about the facts, he may then be asked his opinion about the whole matter. But when the facts are disputed this course is inadmissible, and the question should be stated hypothetically: State v. Klinger, 46 Mo. 228.

If a person is indicted for a crime, and a defense of insanity is set up, and evidence is introduced in support of such defense, a medical expert witness who has heard all the evidence may be asked the following question: "You have heard all the evidence in the case; supposing the jury to be satisfied that the facts and circumstances testified to by other witnesses are true, what is your opinion, as a medical man,

of the state of the prisoner's mind at the time of the commission of the alleged crime?" If the witness should state that the evidence indicated unsoundness of mind, the following question

would be proper : Was the prisoner, in your

opinion, at the time of the doing of the act, under any, and what kind of, insanity or delusion; and what would you expect would be the conduct of a person under such circumstances?" State v. Windsor, 5 Harr. (Del.) 512; Com. v. Rogers, 7 Met. (Mass.) 500.

Witnesses who are not experts may be permitted to state whether they regarded the defendant on trial charged with a crime to be insane at the time of the commission of the alleged criminal act. But this can only be done in connection with their statements of particular conduct, appearance and expressions of the defendant, upon which their opinion is based. They may give their opinion, accompanied by the facts existing within their own knowledge and observation, but they cannot be permitted to give an opinion upon the question whether a hypothetical set of facts would or would not, if true, be evi. dence of insanity; nor from mere evidence which

they have heard others detail: State v. Klinger, supra. See also Farrell v. Brennan, 32 Mo. 328; Boardman v. Woodman, 47 N. H. 120; Dunham's Appeal, 27 Conn. 192.

CHAPTER III.

INSANITY AND ITS LEGAL RELATIONS.

§ 10. Varieties of unsoundness of mind.

That branch of forensic medicine, or medical jurisprudence, which relates to unsoundness of mind in its legal relations, is so important to the medical and legal professions, and in respect to both civil and criminal liability, that the author feels justified in presenting a condensed treatment of the subject in this chapter.

Unsoundness of mind, or insanity, has been distinguished into four varieties, or varying degrees, namely: idiocy, dementia, mania and monomania; but a more concise and perhaps accurate classification would be: amentia, dementia and mania: Guy & F. on Forensic Med. (5th ed.) 172, 173. In the mental conditions indicated by these terms the person is not generally competent to make contracts, nor to dispose of his property by gift or will, or criminally responsible for his acts: See Ray's Med.