THE MONTHLY LAW REPORTER. JULY, 1859. THE TESTIMONY OF MEDICAL EXPERTS, AND THE The admissibility of the evidence of experts in courts of justice, has long been settled, but there is still some discrepancy as to the conditions of its admission, sufficiently important to deserve a most careful consideration. Of late years, cases have become more and more frequent, in which such evidence has been admitted touching the mental condition of one of the parties; and the expert is even allowed to form his opinion, solely, perhaps, on the statements of other witnesses, without any personal examination of the party himself. Counsel, it is true, often endeavor to discredit such evidence, by calling it theoretical and speculative, but if they really believe what they say, they only show a great misapprehension of the nature of the question. The mental condition of a person is manifested by his conduct and conversation, by his acts, his opinions, his manners and deportment, all which are matter of observation, and may come within the cognizance of others besides that of the expert. Although a personal interview may sometimes reveal all that is required, yet, more frequently, from the very nature of the case, the expert obtains from it no satisfactory results. What a man may happen to say or do, in the course of a brief interview with a stranger, may be of little significance, as compared with his mental mani festations during a period of weeks or months, when following the bent of his inclinations without restraint, and with opportunities for carrying his diseased fancies into practical effect. There is nothing singular in this. Medical opinions in regard to other diseases than insanity are seldom founded exclusively on a personal examination of the patient. Facts of the highest importance are often learned from friends and nurses, and could have been learned perhaps only from them, but are none the less valuable on that account. An opinion respecting the mental condition of a person whose sanity is in question, must be founded upon his previous history; at least, so much of it as may be supposed to throw any light upon his mental condition at some particular time. In a doubtful case, it would only indicate the height of ignorance and presumption to arrive at a positive conclusion on the strength of a single interview, or of any other very limited source of information. Indeed, we can hardly conceive of any case requiring investigation, plain enough to be settled in this manner. We know that patients are, every day, received into our hospitals for the insane, on the strongest representations of friends, yet, for days and weeks together, though subjected to the closest scrutiny, they may betray not the slightest indication of insanity. The power of self-control is exhausted, sooner or later, no doubt, and the disease is evinced by unmistakable evidence; but the fact shows conclusively, that the observation of a man's neighbors and acquaintances may furnish far more satisfactory proof of his insanity, than any single examination of the most accomplished expert. Of course, there is no other way of obtaining the object, in cases where the alleged insanity has disappeared, or the party has deceased. It has also been objected to the testimony of experts on this subject, that in consequence of their intimate association with the insane, and their familiarity with the manifestations of the disordered mind, they overlook the sharp distinctions that really exist between the sane and the insane condition. Engrossed as they are in their favorite study, they look at all men through a distorted medium, and thus see insanity where others of a different training, see only the normal operations of the mind. That such persons may often see insanity where it is unperceived by others, is just what might and ought to be expected of men of intelligence and discernment, with abundant opportunities for observa tion. It would be but a poor compliment to them, to say that after all, the delicate shades of mental disease, the faintest possible lines that divide sanity from insanity, those equivocal phases of mind which neither the philosopher nor the practical observer of men attempt to explain, are no more clearly discerned by them than by others. The insanity which lies on the surface is obvious enough to all, but it is only the practised observer of the disease, who can detect it in its milder forms, or when controlled and concealed by the sounder operations of the mind. To him, a look, a gesture, a turn of thought, a mode of expression, scarcely discernible by others, may supply a hint that leads to the most satisfactory proofs. It is not common, we apprehend, to suppose that great attainments in a physical science unfit a man for giving reliable opinions on points connected with it; and it is not easy to see any exception to the general rule in regard to insanity, which, beyond all others, can be understood only by means of a long personal observation. It is no presumption to say that the man who has spent the best years of his life in daily intercourse with the insane, is thereby better qualified, other things being equal, to enlighten a court of justice on difficult questions of insanity, than men without such experience, though otherwise intelligent, and, perhaps, with remarkable knowledge of human nature. The proposition seems too clear for argument or illustration, and yet, in practice, no objection to the value of medical testimony on the subject of insanity, is more commonly or more effectually urged, than the one under consideration. Whatever may be the value of his testimony, the competency of the medical expert as a witness, is unquestioned. The only point not quite settled, is how his opinions shall obtain. In the courts of this State, and of every other, so far as we can learn, the practice is for the expert, after hearing all the evidence in the case, to state the conclusions to which it has led him respecting the mental condition of the party in question. In Commonwealth v. Rogers, 7 Metcalf, (1844,) the court said, "the proper question to be put to the professional witnesses is this: If the symptoms and indications testified to by other witnesses are proved, and if the jury are satisfied. of the truth of them, whether, in their opinion, the party was insane," &c. They are not," the court adds, " to judge of the credit of the witnesses, or of the truth of the facts thus testified by others. It is for the jury to decide whether such facts are satisfactorily proved." For the first time in this country, a different rule was adopted by the federal court of this circuit, in U. S. v. Mc Glue, 1 Curtis, (1851.) The medical experts "were not allowed," says the court, Mr. Justice Curtis presiding, "to give their opinions on the case. It is not the province of the expert to draw inferences of fact from the evidence, but simply to declare his opinion on a known or hypothetical state of facts; and therefore, the counsel on cach side have put to the physicians such states of fact as they deem warranted by the evidence, and have taken their opinions thereon. If you consider any of these states of fact put to the physicians are proved, then the opinions thereon are admissible evidence to be weighed by you. Otherwise, their opinions are not applicable to this case." No authorities are cited for this departure from the universal practice of the country, but they may all be found in an article on Leading Criminal Cases, published in this Journal for April, 1855. What ground they afford for this mode of obtaining the opinions of experts in questions of insanity, will be made sufficiently obvious by referring to a few of the principal cases. At the trial of Earl Ferrers, in 1760, his counsel proposed to ask the medical witness, "whether any and which of the circumstances which have been proved by the witnesses, are symptoms of lunacy." Whereupon, the question being objected to by the Attorney General, Lord Hardwicke, who presided as Lord High Steward, observed that it "tended to ask the doctor's opinion upon the result of the evidence," and that he "must be asked whether this or that fact is a symptom of lunacy." 19 Howell's State Trials, 943.* More recently in Regina v. Francis, 4 Cox, C. C. 57, (1849,) a physician who had heard all the evidence, was asked whether from all he had thus heard, he was of opinion that the prisoner, at the time he did the act in question, was of unsound mind. The court, Baron Alderson, interposed, saying, "I cannot allow such a question to be put;" and on being reminded that the question was so put in McNaughton's case, he added, "I am quite sure that decision was wrong. *This ruling of Lord Hardwicke which we have given in full, precisely as reported, is wonderfully amplified and embellished in Lord Brougham's version of it, contained in his remarks in the House of Lords on the McNaughton case. See 67 Hansard, 614. The proper mode is, to ask what are the symptoms of insanity, or to take particular facts, and assuming them to be true, to ask whether they indicate insanity on the part of the prisoner. To take the course suggested is really to substitute the witness for the jury, and allow him to decide upon the whole case." Shortly after, in Doe d. Bainbrigge v. Bainbrigge, 4 Cox, C. C. 451, (1850,) Lord Campbell ruled out the same question, and for the same reason. In McNaughton's case, Report of the Trial of Daniel McNaughton, by Bousfield & Merrett, 73, (1843,) the question was put to an expert who had heard the whole trial, "judging from the evidence which you have heard, what is your opinion as to the prisoner's state of mind?" and no objection was made. The judges, in their replies to the questions proposed by the House of Lords in consequence of this trial, say, however, that although "where the facts are admitted, or not disputed, and the question becomes substantially one of science only, it may be convenient to allow the questions to be put in that general form, yet the same cannot be insisted on as a matter of right." Such are the principal decisions which furnish the authority in the case of U. S. v. McGlue, for departing from the American practice on this subject. It will be observed that in these cases, the question to the expert, disallowed by the court, was not exactly in the terms of that allowed in the Rogers case, as quoted above. In the former, the opinion is given under the single condition that the expert has heard all the evidence, so that in fact, he passes upon the evidence precisely like the jury. In the latter, there is another condition, he must suppose the evidence to be true. It is not for him to exercise any judgment on this point, but to regard it as all true, without restriction or qualification. This is an important difference, and it may be fairly questioned whether this additional ingredient in the terms of the query, would not have obviated the practical difficulty contemplated by the English courts. It thus becomes the hypothetical case which they require. It may have no foundation in truth. It may have no more reality than the baseless fabric of a vision, yet for the present purpose, it is to be regarded as true, and made the basis of an opinion. It is immaterial, certainly, whether the hypothetical case is presented in the language of the counsel, or of the witnesses, whether it is to be received |