§ 125. PERHAPS the most trying position in which a physician ever finds himself placed before courts is in cases of alleged insanity. While all departments of physical investigation may be considered difficult to explore in their fundamental propositions, particularly when these latter are masked beneath the ambiguities of individual manifestations, that of mental disorder affords the widest field for controversial discussions, and the employment of dialectic ingenuity. Here, the incessant blending of Metaphysics with Physiology opens the door to a world of conjecture, hypotheses and loose inferences, mingling with scientific analysis, and positive clinical knowledge. Law, Theology and Medicine are either at times pitted against each other, or not infrequently confronted by ancient superstitions, crude popular conceits and inherited prejudices. Every man, learned or illiterate, entertains his own views of insanity. To some it is still a sacred disease, an evidence of demoniacal possession; to others but an organic disturbance reflecting itself upon the mental principle. While the world of philosophers, as soon as it investigates this disease in its influences upon moral responsibility, and legal accountability, inevitably divides itself into those who syncopate disease from depravity, looking upon each as a separate, distinct entity, and HAPTER III. ALLEGED INSANITY.-MEDIO-LEA e most trying position in whi d or illiterate, entertains his me al accountability, inevitably dir those who confound them as necessarily correlated in nature, being analogous states with varying degrees of intensity. Among philosophers we shall accordingly find the eidola tribus or specus, among laymen the eidola fori. Among the former, like the medieval battles between Nominalists and Realists, the contest will be hotly waged between the somatic and the psychological schools, thus affording to either party, on the trial, the opportunity of calling to his aid whichever school of experts will best support his own allegations. And, between the two classes of medical disputants, the jury will oftener remain confused than enlightened, since, by unnecessary quibbling over types of insanity it may finally be deduced that all men either are, or have been tinctured with it in some form-(semel insanavimus omnes)-from the prisoner at the bar, to the judge and jury who try him, and accordingly, by carrying this argument to its necessary conclusion, we should reach the reductio ad absurdum of the insane sitting in judgment upon the insane. § 126. From the inherent difficulties attending psychological inquiries carried on in the face of the most critical opposition; one side feeling that they must at every hazard prove insanity, and the other that they must with equal pertinacity, disprove it-between such contending tides of legal dialectics, the position of any expert becomes exceedingly embarrassing. Expected to prove what is not always susceptible of proof, and to define what can only be described, he is required to perform feats of mental legerdemain which would do credit to a Greek rhetorician. Presumed also to be in the interest of the party who calls him, other experts, known to differ from him in their views of the essential causes, or phenomena of insanity, are summoned as direct antagonists, and a glad iatorial contest is thus prepared for the ostensible purpose of enlightening a jury of laymen upon matters, which the profoundest philosophers can not agree in explaining. In this perplexing strife of words, where both court and counsel are often at sea, each one seeking for some plank upon which to float, what can an expert offer that will be satisfactory to all? The general rule of law regulating his testimony is simple and well understood, but the manner of conducting his examination is calculated rather to embarrass than to assist the discovery of truth. Particularly is this the case where he is expected to prove, to the satisfaction of the jury, the correctness of his judgment in a matter, which is not so much an objective fact, as a deduction from professional experience. The preposterousness of the undertaking is only equalled by the pertinacity with which he is often pressed to communicate in a breath, that wisdom in observation requiring years for its attainment. And failing to make others see with his own eyes, the value of his opinion is accordingly impeached, on the ground of its illogical foundation. § 127. It is from this misinterpretation of the office of an expert, that arises that perpetual misunderstanding between lawyers and physicians in trials involving medical testimony. That it is unnecessary all must agree. That it is an obstacle to the discovery of truth, the history of every case serves only to exemplify, and that it is an obstacle to the course of justice a moment's reflection will suffice to show. Under the shadow of these convictions, it becomes the duty of both professions to endeavor to eliminate from the field of their common labors, all causes of, and all provocations to differences of opinion. But it is hopeless to expect this while either profession refuses any concession to the other. Although this is never of diffi cult application in any case, since the good sense of the law, condensed in a maxim pregnant with appropriate suggestiveness, expressly silences all carping criticism-cuilibet in sua arte perito credendum est. An expert's opinion can not be doubted by a layman. He overpeers him quoad his own specialty, and his opinions therefore can only be rebutted by those of other experts. A proper knowledge on the part of counsel of the just limits of inquiry, and of the sphere of possible demonstration possessed by the expert will prevent much needless cross-questioning. There are some questions which should never be asked, because they are simply absurd, and involve either a petitio principii at the start, or select some extraordinarily exceptional case as the basis of an universal law. Why a physical law acts in a particular way is no concern of ours. Its existence is an answer to all inquiries into its necessity. It must suffice us to know how it acts, and not arrogantly inquire why it was so made. § 128. Much of the difference and mutual incomprehensibility of lawyers and medical experts, arises out of the different standpoint from which each party envisages the case. Counsel have a direct interest in making their proofs accord with their allegations. Indeed, their interest in the premises limits them to the necessity of finding nothing beyond this, because, if a different construction can be put upon the propositions advanced by them, the opposite party will be sure to avail himself of it. Consequently, the answers sought to be obtained from the expert are in the nature of absolute and irrefragable conclusions. On his part, the expert having no interest in the issue, seeks merely to resolve the problems set before him in the simplest and most precise way. It is, certainly, not for the interest of his own reputation that 11 he should complicate this problem, or make it an unintelligible one to the jury. The whole tendency of his testimony is, as a matter of policy, towards truth, and every presumption that it is so should weigh in his favor. Counsel having the vantage ground in the examination, should bear this fact in mind, and not commit the error which, in this instance, is more truly an injustice, of questioning the expert exclusively to the limit of proving specific allegations, by narrowing his answers to the simplest affirmations or negations of categorical propositions, thus converting him into a mere party witness. His examination should stand upon a broader foundation than this, or if persistently cramped by a demand for absolute and unqualified answers, then, the expert should carry in his replies so large a measure of explanation as to show, that every fresh affirmation of a truth in physical science, being the application of an universal law to a particular instance, is only a relative phenomenon, not susceptible of positive or absolute proof, and that our best efforts at discovery constitute after all, but an approximation to truth, rather than a mathematical demonstration of it. A good case being in harmony with truth has always a multitude of coincident principles to support it, for truth polarizes all things into which it enters, and causes a wonderful parallelism between even the most apparently dissimilar ones, while error, though propped up by adventitious aids, dares scarcely to move from her precarious foothold. Whenever counsel fears to allow an expert to explain himself in his testimony, by qualifying his language, and seeks to narrow his answers to the baldest possible statements, there at once arises a presumption that either his case is a weak one, or that he feels incompetent to conduct it. Under such circumstances the expert should decline to |