OF THE PRIVILEGES AND DUTIES OF PHYSICIANS AND SURGEONS WHEN SUMMONED
AS EXPERT WITNESSES IN COURTS OF JUSTICE.[180]
_Introductory—Distinction Between Expert Witnesses and Other
Witnesses._—One of the most important positions that a medical man
is called upon to assume by virtue of his professional character, is
the position of expert witness. Most writers on medical jurisprudence
confine themselves, in the discussion of this subject, to presenting
the medico-legal rules which appertain to this position, and concede
its high importance. Before defining what is meant by the term expert
witness, or treating of the rules which determine the status of such
witnesses in court, and their duties, it seems advisable to introduce
the subject by a brief consideration of the distinction between
ordinary witnesses and expert witnesses. When medicine and law are
united in the purpose of investigating facts, and bringing about a
legal determination as to what are or are not facts, they co-operate
with each other in this way. The law furnishes the machinery for the
inquiry and the rules which determine how it shall be prosecuted.
The medical man, however, is called upon as an assistant to the law,
because of his skill and experience in his profession, which enable
him to ascertain and interpret the circumstances from which the facts
sought to be established are to be inferred. Ordinary witnesses testify
concerning matters of observation, the court and jury being endowed
with the sole power to determine the credibility of their evidence
and the true result of their observations. Yet the border line of
distinction between witnesses who testify merely to actual matters
of observation, and those who give their opinions upon and draw
inferences from established facts and circumstances, is a wavering
one. The general rule of evidence is well understood, that hearsay
evidence is inadmissible, and yet, like any other rule, this has its
exceptions which grow out of the necessities of given cases. This is
so because there are and always will be, matters brought before courts
for investigation and determination, long after the witnesses who
personally saw the facts and circumstances of the particular case in
which such matters are concerned have died, or have withdrawn beyond
the reach of the process of the court. Possibly no record in writing
of such facts and circumstances has been left, or if in writing it
lacks the sanctity of being a judicial writing, and hence is no better
evidence than any other form of hearsay evidence. For this reason in
matters of family history, pedigree, custom, and the like, hearsay
evidence is permitted, and is entitled to as much weight as any other
evidence, if the witnesses giving it be trustworthy.
_In Matters of Common Experience Witnesses in General Often State
Conclusions._—Moreover, in matters of common experience, the testimony
of any witness, if carefully analyzed, often shows that he is sometimes
allowed to draw, and state, his conclusions and inferences, instead
of being required to confine his evidence simply to telling in the
strictest possible way, and with the closest limitations, what he
actually witnessed. A good illustration of this is the case of a
person who sees a crime of homicide committed by shooting, and is
called upon to testify in court. He would be allowed to testify that
the defendant, if he could identify the prisoner at the bar as such,
was the person whom he saw fire the shot, although he might not have
examined him with close scrutiny, and might never have seen him before
the crime. In saying that the defendant was the person who fired
the shot, while he would be in terms testifying to a fact, he would
still be drawing an inference, and giving an opinion, based upon his
recollection of the person whom he saw engaged in the act of firing,
and of the likeness or resemblance of such person to the prisoner at
the bar, which would be a matter of comparison and of opinion. So, too,
although he could not see the bullet take its course from the mouth
of the gun and imbed itself in the body of the deceased, yet if he
saw the firing, heard the explosion, saw the flash and smoke of the
powder, observed the direction in which the accused pointed the weapon,
and saw the deceased stagger and fall, he would be allowed to testify
in answer to a direct question whether or not the accused shot the
deceased. And, yet in making up that answer he would be testifying not
simply to a matter of actual observation, but to a conclusion. As it
is in reference to the question of identity so it is as to many other
matters which come before our courts, in all of which the witnesses are
permitted, without objection, to testify to conclusions and to give
answers which are the result of inferences which they draw themselves,
rather than a statement of their actual observations. The law is not
a metaphysical but a practical science, limited and confined by the
practical restrictions which experience has shown must be put upon
it, in order to enable it to accomplish its object of administering
justice between man and man. Men form such conclusions as have been
indicated, instinctively and unconsciously, and it would be practicably
impossible for them to narrate any occurrence without embodying in
their narration some of these natural and unconscious conclusions.
The law, therefore, includes among the matters which witnesses are
permitted to characterize as facts, those daily and hourly inferences
and deductions which all men are accustomed to make, and concerning
which no two men who are properly constituted can greatly differ.
It is true that this practice sometimes leads to error, but it has
grown out of necessity. The greatest safeguard is, that upon the
trial of a question of fact both sides are represented by counsel,
and the opportunity which cross-examination offers to an advocate of
even reasonable and ordinary skill is such, that these conclusions
and inferences may be sifted down through the chain of observation,
and the process of drawing these conclusions and inferences from a
series of facts, tested in such a manner that the improbability,
probability, or truth of any given inference or conclusion may be
determined with substantial accuracy. The illustrations which have
been given above exhibit the simplest form in which so-called direct
testimony can be demonstrated to be not always positive and direct
testimony, but somewhat a matter of inference. Other examples and
illustrations of common occurrence will exhibit still more closely the
line between actuality and opinion. At times it becomes essential to
the determination of a question, that the courts should know whether or
not a person was angry, whether or not he was intoxicated, or whether
or not at a given time, when his mental status was under observation,
he acted rationally or irrationally. Lay witnesses have for many years
been permitted to testify from observation, and without possessing any
special qualification to do so, as to the existence or non-existence of
such conditions as those just mentioned in a person whose actions are
under consideration. It is manifest that in making any such inferences
the witnesses’ testimony is mainly a conclusion based on inference.
Take the case of anger. How shall that be determined? It is difficult
to describe anger. A loud voice, a flushed face, the use of bitter
words, nervous, excitable, demonstrative action—all these symptoms
might occur, or but few of them might occur. So, too, in the matter
of intoxication. It is well known that some individuals exhibit the
effects of intoxicants in an entirely different manner and degree from
others. Some men who are very much intoxicated, so as to be quite
incapable, in the eye of the law, of forming a criminal intent, or of
contracting an obligation which would be valid, may still be able to
walk perfectly straight, or to talk without much confusion. Others,
whose walk and demeanor would indicate a considerable degree of
intoxication, might be mentally clear and unruffled and even stimulated
by intoxicants to precise mental co-ordination and reasoning. Again,
there are persons, as to whom a witness, after stating that he had
observed them, and after stating the particular matters and things in
which such persons were engaged, might with apparent accuracy state
that they acted rationally or irrationally, and yet such persons might
nevertheless, upon further examination, be found to have been acting
according to a particular custom or habit, or idiosyncrasy of long
years’ standing. Thus it is apparent that in each of these cases,
when the witness attempts to state what, out of necessity, the court
treats as a fact—viz., whether a given person is or is not angry,
or intoxicated, or irrational—the witness is really testifying to
the result, in his own mind, of his observations of the condition
and conduct of the person who is under investigation, when compared
with a standard which the witness has erected for himself. Hence such
results are really matters of opinion evidence, pure and simple. Other
examples of a like character are found in statements as to weight,
height, distance, speed, and the like, as to which men of common
powers of observation, who are not strictly experts, are, because
of convenience and necessity and the probability of reasonable and
ordinary accuracy, commonly permitted to give their own judgment and
conclusions as evidence.
_All Witnesses Often Permitted to Draw and State Conclusions in Matters
involving Numerous and Complicated Details._—Thus the practical
necessity of the administration of justice has led to the establishment
of the rule, that where the details of an occurrence are numerous and
complicated, and are incapable of precise description by ordinary
observers, witnesses are permitted to use, in testifying, general
expressions which really embody their conclusions from the facts or
details observed by them. Greenleaf on Evidence, Section 440, note A;
Wharton on Evidence, Section 434.
Wharton says that “the distinction between expert witnesses and
ordinary witnesses is this: the non-expert witness testifies to
conclusions which may be verified by the adjudicating tribunal; the
expert, to conclusions which cannot be so verified. The non-expert
gives the results of a process of reasoning familiar to every-day life;
the expert gives the results of a process of reasoning which can be
determined only by special scientists.” See also People _v._ Fernandez,
35 N.Y., 49. People _v._ Deacons, 109 N.Y., 374-382.
This learned writer (Wharton) also says, at Section 437 of the same
treatise:
“Where conclusions depend upon facts whose evidential weight can only
be determined by those familiar with a particular specialty, then these
conclusions may be given by experts in such specialty.” Such also is
the exact derivative meaning of the word expert, it being derived from
the Latin word “_expertus_,” meaning, literally, “experienced,” and
hence skilled by experience.
_Functions of an Expert Witness Essentially Judicial._—It is the
function of an expert witness to reason about facts, to explain their
connection with one another, and to draw conclusions and inferences
from them. Hence, a witness, however expert in any ordinary sense in
his specialty, when he is called upon merely to narrate facts which he
has observed, is an ordinary witness, and is governed by the same rules
which apply to the ordinary witnesses. When, however, he is called
upon, in addition to recounting facts, to explain or interpret them by
reference to assumed facts, he becomes properly an expert witness. It
thus appears that an expert witness must necessarily perform a part
of the duties which devolve upon the court or the jury. His position
is, therefore, essentially judicial, except that he has no power to
enforce his determinations by judicial process. The importance and
responsibility which the law thus confers upon an expert are of the
highest character. He ranks the coequal with the tribunal itself in his
peculiar province, so far as relates to his individual responsibility.
That this should tend to elevate such witnesses to a high social
position, and ought to require the most exact and faithful integrity of
purpose and statement, is self-evident.
_Difference Between Status of Expert Witnesses in France and Germany
and in the United States and England._—In some foreign countries,
notably in Germany and in France, experts in medico-legal matters have
an assured official position, and are generally not allowed to be
selected at hap-hazard according to the will or the length of the purse
of those who need their services. The consequence of this method of
obtaining expert evidence is, that expert witnesses in those countries
command a high measure of respect and honor.
Unfortunately, however, in this country, where the opposite practice
prevails, the weaknesses of human nature are such that the common
people, newspapers, lawyers, and even the courts in some recorded
opinions and decisions, have come to express a great want of confidence
in the weight and value of expert testimony. This deplorable result
of a bad system of procedure is universally recognized, yet our State
legislatures have as yet refrained from attempting to correct it.
Hence, in considering the value of expert testimony _in matters of
medical jurisprudence_, it must be conceded, in the first instance,
that the difference between the system prevailing in this country
and in England, and that which prevails on the Continent, notably in
Germany and France, has not tended to raise but to depress the value of
such testimony in the first-named countries. In the latter countries,
the experts upon medico-legal questions are officers of the court,
or are treated as such. They form, in a sense, a part of the judicial
system, and the expression of their opinions consequently carries with
it great weight. Moreover, under the system which prevails there,
it has been possible for men to be educated up to a high degree of
skill and experience in the particular branches of physiological or
psychological or physical investigations which they pursue, while here
in America, and to a certain extent also in England, experts are such
for other reasons, and by the operations of other causes, than the fact
of their permanent employment in that capacity. As a general thing they
become skilled in their profession or in the particular branches of
it in which they practise as specialists, and are summoned to testify
simply because they are selected by one party or another to a lawsuit.
_Mr. Wharton’s View of this Question in the Main Hostile to the
Prevailing System Here._—The effect of the methods which thus prevail
has not been entirely to the advantage of the medical profession or of
our courts. Wharton, in his work on “Evidence,” Section 454, observes
upon this point: “When expert testimony was first introduced it was
regarded with great respect. An expert was viewed as the representative
of a science of which he was a professor, giving impartially its
conclusions. Two conditions have combined to produce a material change
in this relation. In the first place it has been discovered that no
expert, no matter how learned and incorrupt, speaks for his science as
a whole. Few specialties are so small as not to be torn by factions,
and often the smaller the specialty the bitterer and more inflaming and
distorting are the animosities by which these factions are possessed.
Particularly is this the case in matters psychological, in which there
is no hypothesis so monstrous that an expert cannot be found to swear
to it on the stand, and to defend it with vehemence. ‘_Nihil tam
absurdo_,’ which being literally translated means that there is nothing
so absurd that the philosophers won’t say it! In the second place,
the retaining of experts by a fee proportioned to the importance of
their testimony is now as customary as is the retaining of lawyers. No
court would take as testimony the sworn statement of the law given by
counsel retained on a particular side, for the reason that the most
high-minded men are so swayed by an employment of this kind as to lose
the power of impartial judgment; and so intense is this conviction that
in every civilized community the retention by a judge of presents from
suitors visits him not only with disqualification but disgrace. Hence
it is that, apart from the partisan character of their opinions, their
utterances, now that they have as a class become the retained agents
of the parties, have lost all judicial authority and are entitled only
to the weight which sound and consistent criticism will award to the
testimony itself. In making this criticism a large allowance must be
made for the bias necessarily belonging to men retained to advocate
a cause, who speak not as to fact but as to opinion, and who are
selected, on all moot questions, either from their prior advocacy of
them or from their readiness to adopt the opinion to be proved. In this
sense we may adopt the strong language of Lord Kenyon, that skilled
witnesses come with such a bias on their minds to support the cause
in which they are embarked, that hardly any weight should be given to
their evidence.”
This author then proceeds to show that under the civil law system the
conclusions of experts were formerly treated as unassailable facts,
but under the English and American common law system this is not the
case, but their testimony is to be weighed by the court. He says:
“The grounds on which the conclusion is reached may be asked for: the
expert’s capacity for drawing conclusions, as well as his premises,
may be assailed. Cases of conflict are to be determined, not by the
number of witnesses, but by the weight of their testimony, and though
the opinion of an expert of high character may be entitled to great
respect, yet if questioned, its authority must ultimately rest upon the
truth, material and formal, of the reasoning on which it depends.”
Judge Davis, of the Supreme Court of Maine, in Neil’s case (cited
in Wharton and Stille’s “Medical Jurisprudence,” Vol. I., Section
294), said: “If there is any kind of testimony that is not only of no
value, but even worse than that, it is in my judgment that of medical
experts. They may be able to state the diagnosis of a disease more
learnedly, but upon the question whether it had at a given time reached
a stage that the subject of it was incapable of making a contract, or
irresponsible for his acts, the opinions of his neighbors, of men of
good common sense, would be worth more than that of all the experts in
the country.”
Such stinging criticisms as these, and others which might be cited,
of a like character, may not be always merited. It is certain that
medical experts’ opinions, if fully enlightened by scientific research
and free from partisan bias, ought to occupy a position like that
of judicial opinions in weight and decisiveness upon the questions
submitted to them. Such was the position occupied in the public
estimation, and in that of judges and counsel, by the great Dr. Caspar
in Germany, and Foedere or Pinel, and others since their time, in
France. But this position was acquired chiefly because of the fact
already mentioned, that under the system of administration of justice
which prevails in those countries these great men were regarded, and
acted, as a component part of the judicial system. They were called
in as officers of the law to assist the court in forming a judgment,
and determining disputed questions of fact, in cases involving life
and death, or the devolution of property, where scientific experience,
knowledge and skill, not possessed by judges or by counsel, was
necessary for the determination of the questions involved. The root
of the evil in America is, as already pointed out, to be found in
the system which allows parties to retain and pay their own experts
without any substantial restrictions. Sooner or later, among the other
reforms in our judicial system, it will be found necessary to reform
this evil by the enactment of laws requiring that the witnesses in
medico-legal cases, particularly those in which a crime is alleged
to have been committed, shall be designated by the court, or by some
public authority, and paid from the public treasury instead of by
the parties. Such experts would then occupy their proper position of
special counsel, advising and assisting the legal counsel and the
court, but they would not be taken out of this sphere and put in the
utterly inconsistent one of witnesses. Their status and their duties
would be as clearly distinguished from that of expert witnesses as now
known, as the status and duty of the lawyer are from the status and
duty of the judge. The present system has been said to be very much
like putting a lawyer, who has just argued his client’s case, on the
bench to decide it. Whether experts should be appointed as permanent
government officials, like our judges, or should be selected specially
for each case like juries, referees, or arbitrators, and in the latter
event whether they should be nominated by the parties and selected by
the court from such nominees, or otherwise, are all questions of detail.
Our judges and lawyers seem slow to recognize the fact that the duties
of experts are judicial, or at least quasi-judicial; to pass upon
certain facts which neither the court nor the jury can understand
without their aid. But, as we have seen from the citations just given,
judges and lawyers have fully recognized the unreliability of expert
testimony, produced as it now is in England and in this country at
the whim and selection of the parties and paid for, much or little,
according to the means of the parties.[181]
_Method of Preliminary Examination of Experts—On Medical Questions a
Licensed Physician Presumed Competent._—As the system exists here, the
only power that the court has over the selection of an expert, is to
determine, in advance of his testimony and of the elucidation of his
opinions, whether or not he is competent as an expert. But this power
affords little or no check or restriction, because in the effort to get
all the light that is possible upon the questions under consideration,
and to avoid unduly interfering with counsel in the conduct of the
case at bar, the practice has become universal, and is recognized in
the decisions and text writers, of permitting any medical man who has
a license to practise his profession, to testify as an expert, and to
give his opinion as such on any question cognate to his profession.
This is so without regard to the amount of study and experience he
may have had in the particular matter under consideration. The naked
fact that he is licensed to practise is enough. He then—that is,
after testifying that he is a practising physician—is clothed with
the garment of authority. The only way in which his knowledge can be
tested is by cross-examination as to his experience and skill, and
possibly by contrasting him as he appears upon the witness-stand and
his history as he gives it, with other and more or less experienced and
skilful men who follow him.
The rule is, that when a witness is produced to give an opinion on a
medical question, he is interrogated by the counsel who produces him
as to his qualifications. At this point, before he is allowed to give
his opinion, it is proper and customary that the counsel upon the other
side of the case should be allowed an opportunity to cross-examine
as to his competency, and then the court determines whether or not
he is a competent witness. If the court pronounces him competent, a
hypothetical question is put to him stating the facts of the case, as
the counsel interrogating him claims them to be established by the
evidence, and the expert is then asked to give his opinion on the
question at issue, based upon an assumption that the facts stated are
truly stated. Then the opposing counsel has the right to cross-examine,
and to ask his views and opinions upon the same question at issue, but
assuming as true other and different facts or premises, as he claims
them to be established by the evidence. This often involves a test of
wit and intelligence, and of forensic acumen, between the counsel and
the witness, which serves very little useful purpose, except perhaps to
elucidate more strongly than has been here stated the defects of the
system which now obtains. It is also not unusual, and in fact is the
result of the workings of human nature, that under the manipulations of
counsel skilled in cross-examination, skilled in methods of indirection
in stating facts, and armed with the powerful weapon of the rule
which permits them to insist upon a categorical yes-or-no answer to a
question, the jury and the court become confused, the witness loses
his temper, or becomes affected more strongly than ever before by bias
against his persecutors, as he feels them to be, and the examination
ends in a farce. This is not always the case, and the illustration
given is an extreme one. Like the citations from judicial criticism of
expert testimony which have been given, these matters are only adverted
to here as danger signals, a warning to both professions, and with an
earnest suggestion of the necessity of reform.
EXPERTS, HOW SUMMONED INTO COURT.
_They Must Obey the Summons and Appear and be Sworn. In General they
need Not Give their Opinions unless Duly Compensated._—An expert
witness is brought into court like an ordinary witness by the usual
process of the court. This process is, under the American system, an
ordinary subpœna, and, being process of the court, whether or not he
has been paid or promised compensation for giving his opinion he must
obey the process to the extent at least of appearing in court when
called, to be sworn. Interesting questions have been raised as to his
obedience to the subpœna to the extent of testifying when he has not
been compensated. It has been argued, and the argument is sustained
by the decisions of courts of high authority in some States, that
his knowledge and skill, acquired by study and by experience, is his
property, of which he cannot be deprived without just compensation,
under his constitutional rights guaranteed to him by the organic law
of this country. On the other hand, in some other States it has been
held that he is so far a necessary part of the judicial system that he
may be called upon to give the results of his experience, knowledge,
and skill forming his opinion, without payment other than the ordinary
compensation to witnesses. It is believed, however, that the better
opinion is the former; that he does not stand on the same footing as
an ordinary witness, whose province it is to testify solely to matters
of observation of fact, but that he stands in the position of one who
has something to give; something to impart in the way of knowledge or
experience, which is his property as much as any other thing movable or
immovable of which he is possessed.
A somewhat different question has arisen in the case of a witness who,
like a family physician or attending physician, has learned facts
and has been paid for his attendance, or who exacts payment for his
attendance, as a physician from his patient, and this question is;
when such a professional man has been called upon to testify to the
information he thus attained, whether he can be asked for, and required
to give, opinions based on those facts? Necessarily, having learned the
facts by observation, such as the appearance, symptoms, and actions of
the patient, he is, when testifying as to these matters, nothing more
or less than an ordinary witness, because he is testifying to matters
of observation. As to these matters public policy requires, except so
far as it has been modified, or rather extended, by our statutes which
forbid testimony as to privileged communications, that he must testify,
the same as any other witness. But suppose that, having so testified to
the facts, he is asked to give his opinion; for example, in an insanity
case, whether the symptoms that he found in his patient led him to the
belief as a professional man of experience and skill that his patient
was sane or insane. The question is, Can he be compelled to give that
opinion, if he chooses to decline to give it without the promise or
assurance of further compensation than the mere _per diem_ fee and
mileage of an ordinary witness? The best authority is to the effect
that he must so testify, the reasoning of the court being that his
opinion is only a part of what he derived from his original relation of
physician to his patient. Wright _v._ The People, 112 Ill., 540; same
case, 33 Alb. L. J., 79.
_Same Rule in Civil and Criminal Cases._—The rule is the same whether
the professional man is called to testify as an expert in civil or
criminal cases. In either one he is not obliged to give an opinion as
such, independent of a personal knowledge of the facts in the case,
without being paid or assured reasonable compensation therefor. His
proper course of conduct is, when he has obeyed the subpœna and is in
the presence of the court and has been sworn, and the questions put
by counsel disclose that the object of his examination is to elicit
from him an opinion, to state to the court that he has not been paid
any other compensation than that of an ordinary witness, and that he
respectfully declines to give an opinion in the case as an expert,
without compensation proportionate to the value of his opinion.[182]
_Whether Witness Competent a Question for Court in Limine._—After
the expert is placed upon the stand, as we have seen, the counsel
upon the side of the case by which he is summoned interrogates him
as to his capacity, the purpose of the interrogation being that his
answers shall qualify him and show him to be an expert. Whether or
not he is an expert so as to permit the giving of his opinion as
part of the case to go to the jury, is for the court to decide _in
limine_, that is, at the threshold, and as a matter of discretion, and
the exercise of that discretion, if fair and reasonable, will not be
disturbed upon appeal by the higher court. It is permissible, but also
discretionary, after the counsel calls the witness and has apparently
qualified him, for the counsel upon the other side to cross-examine
the witness as to his qualifications before he is examined in chief,
with a view of determining whether or not there are limitations upon
those qualifications which should prevent the court from permitting him
to testify as an expert. The general rule is as stated by Greenleaf
in his work on Evidence, Sec. 440, that it is not necessary that the
medical expert should have actually practised his profession. Nor is it
essential that the witness should belong to any particular school of
medicine. The law does not undertake to pass upon conflicting theories
of medical practice, in determining the question of the qualification
of a medical expert. It is proper, however, for counsel to inquire as
to what school of medicine the witness is an adherent, because of its
importance in weighing the value of his testimony after it has been
given.
_Persons Not Duly Licensed Sometimes Held Not Competent._—It has
also been a mooted question in those States where it is necessary, in
order to enable a person to practise physic or surgery, that he should
be licensed, whether a person practising without a license, however
extensive his reading and practice, would be considered qualified as
an expert witness in a court of justice. This point, so far as diligent
examination discloses, has not been determined in any reported case,
although it has been suggested at _nisi prius_ and has been, in one
instance within the knowledge of the writer, decided that he is not
to be considered an expert in matters involving medical knowledge and
skill. The reasoning of the court was that the policy of the State
is to prohibit persons not possessing the qualifications required
to obtain a license, from acting in any capacity as professors and
practitioners of medicine or surgery. If the witness is a member of
the profession, legally qualified as such, it has been held that he is
sufficiently qualified as an expert if he shows that he possesses the
average ability of members of his profession. Hall _v._ Costello, 48
N. H., 176; Tellis _v._ Kidd, 12 Ala., 648; Wharton on Evidence, Sec.
446; Rogers on Expert Testimony, Secs. 17 and 18; Slocovich _v._ Orient
Mutual Ins. Co., 108 N. Y., 56.
As to the question whether it is necessary that the witness should
actually have practised his profession, see the last-cited text-writer,
Secs. 43 and 44, who seems to have entertained views opposite to those
stated by Professor Greenleaf.
Wharton on Evidence, Sec. 439, states the rule as follows: “He must
have special, practical acquaintance with the immediate line of inquiry
more than a mere vague, superficial knowledge. But he need not be
acquainted with the _differentia_ of the specific specialty under
consideration.... A general knowledge of the department to which the
specialty belongs would seem to be sufficient.”
_Interested Persons may still Testify as Experts._—Since the law
forbidding interested persons from being witnesses has been changed,
it has been suggested that an interested person although otherwise
qualified might not be a competent witness to give an opinion as an
expert. But the established doctrine is that he may give such an
opinion; the weight of it, however, would be for the jury to determine.
Greenleaf on Evidence, Redfield’s edition, Sec. 440, citing Lockwood
_v._ Lockwood, 2 Curtis, 309; Dillon _v._ Dillon, 3 Curtis, 96, 102.
See also Dickinson _v._ Fitchburg, 13 Gray, 546.
_Testimony of Expert, how Impeached._—Sometimes, on cross-examination
or otherwise, the fact becomes known that the witness who is proposed
as an expert has expressed an opinion on the subject in hand contrary
to that which he has given upon the witness-stand, and the question has
been raised as to establishing that fact at the outset and before his
testimony goes before the jury, in order to enable the trial judge to
determine whether he is competent. The rule in that case is that the
testimony as to his prior expression of opinion is not to be received
at that time, but will come properly up as rebuttal, he having been
asked upon his cross-examination, giving time and place, whether he
has made the statements attributed to him. An expert witness may in
other respects be impeached like any other witness, that is, by the
oaths of persons who know him and have known his reputation, and who
testify that his reputation for truth and veracity is bad and that they
would not believe him under oath. He may also be impeached by producing
witnesses to prove that his special knowledge or technical skill is
not reliable or adequate to the undertaking which he has assumed. But
this testimony must be from personal knowledge of the man and not
from general reputation. Wharton on Evidence, Sec. 437; Le Rose _v._
Commonwealth, 84 Pa. St., 200.[183]
_General Rule as to Required Amount of Skill and Experience
Stated._—The general rule may be stated thus, as derived from these
and other authorities:
The extent of the previous study and investigation, and the amount of
skill and information which must be shown, will depend upon the facts
of each particular case. But some special and peculiar knowledge or
skill must be established, the amount of it to be determined by the
trial judge in his discretion. The possession of such knowledge and
skill is presumed in medico-legal cases if the witness is a licensed
practitioner.
_Some Practical Suggestions as to Conduct of Witnesses on the
Stand._—In this preliminary examination, the conduct and demeanor
of the witness are of no little importance, because it is then and
there that he makes his first impression upon the court and jury.
He should be perfectly open and unreserved in stating his means of
special information, in explaining what are the limits of his personal
experience and the extent of his reading; but, at the same time, it
would be well for him to avoid all appearance of self-glorification
and all tendency to exaggerate his individual acquirements. Often has
it occurred that expert witnesses of undoubted capacity and honesty,
who are unfortunately grandiose and self-assertive in their manner,
have, however honest and able they might be, lost entirely their weight
with the court and jury by undue self-complacency and exaggeration of
their personal qualifications, during their preliminary examination.
This is a matter requiring tact and judgment and nerve, and should be
fully understood between counsel calling him and the witness, before
the witness is placed upon the stand. In that event, it will be quite
safe for the witness to closely follow the questions of counsel by his
answers, and to volunteer little or nothing. If his answers are not
full and complete enough, counsel can renew the question in the same or
in other form or carry the matter into greater detail. If, on the other
hand, his answer is too full or he appears too eager, he may create
a prejudice against him which nothing can overthrow, and which the
art of counsel upon the other side in cross-examination and in making
comments upon his testimony when summing up before the jury, will very
effectually use to destroy his weight as an expert.[184]
_Scope and Extent of Examination of Expert Witnesses._—Having stated
how experts may be summoned and qualified, it remains to consider the
scope and extent to which they may be examined.
The advancement of the sciences and the progress of research in special
fields of knowledge have made expert testimony of large importance
during the present century. The basis of its admission is the fact
that there are certain processes of reasoning which an ordinary jury
is incapable of performing, even with the assistance of courts and
lawyers. Oftentimes in the administration of justice in our courts,
proof is given of circumstances which although admitted would have
little or no significance in the mind of an ordinary juror, and
which he would be unable to contrast and compare with other facts,
successfully, without the aid of those more familiar with scientific
matters and the inductive process of reasoning than he is. In such
cases it is necessary that the jury should be specially enlightened
by persons who have, through training, skill and experience, acquired
the power to enlighten them. A common instance and illustration of
this matter is to be found in the case of homicide by poisoning. A
human body is found dead; externally there may be no _indicia_ to
show positively the cause of death. Under such circumstances the
laws of all civilized countries permit what is called a post-mortem
examination by skilled physicians, who, finding no external evidences
of the cause of death, are permitted by the officers of the law to
remove the internal portions of the body for special and careful
examination. If this discloses traces of inflammation or of lesions of
an abnormal character, further power is vested in the authorities to
have at the expense of the State a chemical examination of the internal
organs. If this examination, which is necessarily long and excessively
technical, results in the discovery of any poisonous substance, such
as would produce death, and if it is found in sufficient quantities to
produce death, these persons who made the post-mortem examination and
discovered the outward indications of the administration and effects
of the poison, and the chemists who discovered the poison itself in
the tissues of the body, in sufficient quantities to produce death,
are called as experts before the jury. The post-mortem examiners
explain what the appearance of the body was, as distinguished from the
appearances of the body of an individual who had died from natural
causes. The chemist describes his course of experimentation, the
various deductions which he made from his experiments, the tests which
he applied in his investigation in discovering poison, and is then
allowed to testify that the poisonous substance was found in sufficient
quantities to produce the physical appearances which the post-mortem
examiners have described, and to accomplish the death of the human
being in whose body the poison was found. It is obvious that the power
of observation and the skill, which the skilled chemists and physicians
used as the basis of their reasoning in this case, were such as an
ordinary man, unskilled and inexperienced, would not possess, and the
ability to use them must have come from the study of treatises on
such subjects, and from teaching and experience, to such an extent as
to entitle the persons so testifying to be considered by the courts
as qualified to express an accurate and sound opinion on the matters
and things under investigation. Thus it appears how, in such cases, a
departure became essential to the successful administration of justice,
from the strict rule that witnesses shall testify solely to matters of
fact and observation, and why it has long been considered that some
witnesses must be allowed to testify to opinions and conclusions.
Again, in a like case, a body is found bearing evidences of wounds or
bruises. The question to be determined is whether they were inflicted
before or after death; if before death, whether they were sufficient to
cause death. Some wounds and injuries might be sufficiently apparent
and dangerous so that the common, inexperienced eye would at once
detect that they were sufficient to cause death. But in most instances
this is not the case, and in such instances the testimony of experts
is required by the necessity of the case, to show that the wounds and
injuries were sufficient to cause death.
_The General Rules Stated as to Subjects for Expert Testimony._—Hence
the general rule is, that wherever the facts to be investigated
are such that common experience and knowledge of men do not enable
them to draw accurate conclusions, but are such that the study and
experience of specialists do enable such specially endowed persons to
draw accurate conclusions, then the inferences and deductions they
have drawn can be testified to by those who qualify themselves before
the court as persons having sufficient skill and experience as such
specialists to entitle them to give opinions. The cases in which expert
testimony is permitted to be given are set forth in Rogers on Expert
Testimony, Sec. 6, quoting from Jones _v._ Tucker (41 N. H., 546), as
follows:
“1. Upon questions of science, skill, or trade, or others of like kind.
“2. Where the subject-matter of inquiry is such that inexperienced
persons are unlikely to prove capable of forming a correct judgment
without such assistance.
“3. Where the subject-matter of investigation so far partakes of the
nature of science as to require a course or previous habit of study in
order to the attainment of knowledge of it.”
So also Chief Justice Shaw of the Supreme Court of Massachusetts, in
New England Glass Co. _v._ Lovell (7 Cushing, 319), said:
“It is not because a man has a reputation for sagacity and judgment
and power of reasoning that his opinion is admissible in testifying
as a witness. If so, such men might be called in all cases to advise
the jury, and it would change the mode of trial; but it is because a
man’s professional pursuit, or his peculiar skill and knowledge of some
department of science not common to men in general, enable him to draw
inferences where men of common experience, after all the facts have
been proved, would be left in doubt.”
To the same effect see Muldowney _v._ Illinois Central R. R. Co., 36
Iowa, 472; Wharton on Evidence, Sec. 436; Greenleaf on Evidence, Sec.
441.
_Qualifications of this General Rule._—The extent to which an expert
witness can go in giving his opinion is limited to matters of science
and skill, and does not extend to the expression of views on matters
of legal or moral observation, or the manner in which others would
probably be influenced if the parties had acted in one way rather than
in another. Campbell _v._ Richards, 5 B. & Ad., 345.
So it has been held that the question whether a physician has honorably
and faithfully discharged his duty in a given case, either to his
medical profession or to his patient, is not a question of science but
of pure ethics, upon which the jury is as competent to decide as any
one else, and in such a case an opinion would not be allowed to be
given either by another medical practitioner or by a professor in the
science of morals. Rogers on Expert Testimony, Sec. 11, citing Ramadge
_v._ Ryan, 9 Bing., 333.
There are also some matters of fact which apparently transcend the
dividing line between common experience and judgment and scientific
experience and judgment, as to which expert testimony is not
receivable, but the jury and court must weigh the facts and draw the
inferences for themselves. An interesting example of this is found in
the case of Manke _v._ The People, 78 N. Y., 611 (17 Hun, 410), cited
in Stephens’ “Digest of the Law of Evidence,” p. 107, note H, decided
in the New York Court of Appeals a few years ago. In that case one
Adolf was killed by a gunshot, and pieces of paper were found near the
scene of the homicide bearing certain marks. An expert was called upon
to say whether they were powder-marks, and whether the condition of the
paper was such that in his opinion it was wadding which had been fired
from a gun. This evidence was held to be inadmissible by the General
Term of the Supreme Court, and this decision was affirmed by the Court
of Appeals. These courts held that the question as to whether this was
a wad fired from a gun was a matter which the jury was as competent to
judge of as the witness. In delivering the opinion at General Term,
Presiding Justice Talcott said that this case was very close to the
border line, but in his judgment it was beyond the province of experts
and within the province of jurors.
Nevertheless, in that case the evidence of chemists who had examined
the wadding, and had discovered the marks on it which were said to
be powder-marks, and upon analysis had determined that they were
powder-marks, or that they were marks of powder which had exploded,
would have been clearly admissible.
The subjects concerning which medical men may be called upon to
testify as experts are as numerous as the diseases, injuries, mental
and physical conditions of the human race which fall within the range
of the practice of medicine and surgery. It is therefore practically
impossible to give them in detail.[185]
_Practical Suggestions and Admonitions Embodied in Rules._—It
is deemed advisable that the following practical suggestions and
admonitions to physicians, concerning their duties as expert witnesses,
shall here be given.
First: A physician should refuse to testify as an expert unless he is
conscious that he is really qualified as an expert.
Second: After accepting the responsibility, his first duty should be
to make a diligent examination and preparation for his testimony,
unless it is upon a subject with which he is familiar and which he
is satisfied that he has already exhausted, by reading the best
authorities that he can find, and by careful reflection upon particular
questions as to which his opinion will be asked.
Third: Where he is to make an examination of facts, such as the
post-mortem examination of a body, a chemical analysis or an
examination of an alleged insane person, he should insist upon having
plenty of time and full opportunity for doing his work thoroughly. He
should take particular pains to make his examination open and fair,
and, if possible, should invite opposing experts to co-operate with him
in it.
Fourth: He should be honest with his client before the trial in
advising him and giving him opinions, and upon the trial should
preserve an absolutely impartial attitude, concealing nothing,
perverting nothing, exaggerating nothing.
Fifth: On the preliminary examination as to his qualifications as a
witness he should be frank and open in answering questions. He should
state fully the extent and the limits of his personal experience and of
his reading upon the subject, without shrinking from responsibility,
yet without self-glorification.
Sixth: He should be simple, plain, and clear in his statement of
scientific facts and principles, avoiding the use of technical
language, and trying to put his ideas in such form that they will be
grasped and comprehended by men of ordinary education and intelligence.
Seventh: He should avoid stating any conclusions or principles of which
he is not certain, but having an assurance that he is right he should
be firm and positive. He should admit the limitations of his knowledge
and ability. Where a question is asked which he cannot answer, he
should not hesitate to say so; but he should refuse to be led outside
the subject of inquiry, and should confine his testimony to those
scientific questions which are really involved in the case, or in his
examination of the case.
Eighth: And finally, he should always bear in mind that at the close
of his testimony an opportunity is usually given to him to explain
anything which he may be conscious of having said, which requires
explanation; and partial statements which need a qualification to make
them a truth. This is the physician’s opportunity to set himself right
with the court and with the jury. If the course of the examination has
been unsatisfactory to him, he can then, by a brief and plain statement
of the general points which he has intended to convey by his testimony,
sweep away all the confusion and uncertainty arising from the long
examination and cross-examination, and can often succeed in producing
for the first time the impression which he desires to produce, and can
present the scientific aspects of the case briefly and correctly.
Probably no man was ever so gifted as to be able in practice to carry
out all of these principles in giving medical testimony. If he could,
he would be the ideal expert witness. But the principles are, after
all, simple and easily followed in the main. Any physician who knows
his subject and who has a clear head and the ordinary faculty of
expression, by observing these principles can make himself invaluable
as an expert witness. There is no branch of the profession which brings
a broader fame, greater influence, or larger emoluments than this.
There is no branch, on the other hand, in which men of real ability
make more lamentable failures.