[Reprinted from the Boston Medical and Surgical Journal of March 30, 1899.] 
MEDICAL EXPERT TESTIMONY.1 
JOHN C. IRISH, M.D., LOWELL. 
This article is offered, in the main, as a defence of the medical expert 
and of medical expert testimony as it is presented in our courts to-day. It 
is also offered as a protest against the scathing criticisms that this kind of 
testimony has so often received of late at the hands of many lawyers, and, I 
regret to say, of many members of the medical profession as well. In 
fact, I am not sure but that these criticisms have come fully as much from 
physicians as from lawyers. For the last few years the various medical pub- 
lications have been teeming with articles sharply criticising the character of 
medical expert testimony, and, at the same time, suggesting various modes 
of improvement in the securing of this class of evidence. The general trend 
of this criticism, both by lawyers and doctors, has been to characterize this 
class of evidence as confusing, misleading, valueless, mercenary and false, and 
an unbiased reader knowing nothing of the facts in question would be 
irresistibly led to the conclusion that a large proportion of medical gentle- 
men, when they were placed upon the stand as experts, become unscrupulous 
partisans and oftentimes untruthful contestants in the case. And I especially 
protest against this misrepresentation coming from members of the medical 
profession, nearly all of whom, at one time or another, have occasion to be 
employed as expert witnesses in our courts. 
When we recall the high standard of honor by which the conduct of the 
great mass of our profession is regulated in every other relation of life, 
through all the cities and villages of New England, and recall, too, the uni- 
versal confidence and respect reposed in them by the communities in which 
they live, and that in all matters of business, education and health that engage 
the attention of public-spirited citizens we find the members of our pro- 
fession always in the lead, and always active in every movement that makes 
for the well-being of our citizens at large, it would indeed be very strange 
if in one single relation this great body of men, so honorable and so honored, 
should become mercenary and untruthful as medical experts in our courts. 
The whole fact is that when we sift this vituperation down, and get really 
at the bottom of the ground for it all, we simply find that it rests upon this 
one fact, that medical experts very frequently, in the trial of a particular 
cause, give very different and oftentimes conflicting opinions. Now, we 
will all agree that in the trial of very many causes, and in fact all those 
causes that have to do with the physical and mental condition of the litigants, 
1 Read before the Massachusetts Medico-Legal Society, February 1,1899, Medical Expert Testimony. 
medical expert testimony is a necessity. If we could thoroughly scan,that 
broad realm of medical jurisprudence in which medical expert testimony 
necessarily plays an important part we would find that many seeming con- 
tradictions of the different expert witnesses would be reconciled, and we 
would see, too, that the irreconcilable conclusions arrived at were in no 
way inconsistent with the perfect integrity and honestness of purpose of the 
men who have testified; but the necessarily narrow limits of this article will 
allow us to cover only a few examples here and there, yet I am sure these 
will be enough to show that the medical expert is usually unjustly assailed. 
I do not mean to say that there are no physicians who as medical experts 
are mercenary and untruthful, but I do maintain that their number is exceed- 
ingly small, and that the appearance of such men in our courts, bringing 
disgrace to medical expert testimony, is of infrequent occurrence. 
For the past twenty-two years the Commonwealth has relied, in the main, 
for its expert testimony in its prosecution of criminals charged with man- 
slaughter and murder upon seventy-two expert witnesses, most of whom are 
members of this Society, and in the great number of prosecutions during this 
long time I do not know of a single instance in which one of these experts 
of the Government, in his statement of facts, or in the giving of his opinion 
as an expert, has ever been accused, or suspected, of swerving from the 
exact truth for the aid of the prosecution, or for the harm or benefit of the 
accused. 
Turning now to the civil courts, we come to that broader field of judicial 
inquiry which requires the aid of the medical expert. Here we encounter 
in great numbers and endless variety those suits for redress for every kind of 
personal injury, and in the trial of these cases the medical expert is an indis- 
pensable adjunct. Taking as an example one of those suits for personal in- 
jury in which the plaintiff is asking for compensation, let us look for one 
moment at the kind of testimony that is sought from the expert witnesses 
of both plaintiff and defendant. We find, as a general rule, that the medi- 
cal experts are giving their testimony in two very distinct directions ; that 
is, we find them testifying both as to matters of fact and questions of opinion. 
The medical gentlemen called will usually consist of the doctor who has at- 
tended the patient, and the several medical experts on each side, who have also, 
on one or more occasions before the commencement of the trial, examined 
the plaintiff. Therefore, all of them are in a position to testify, to a greater 
or less extent, as to matters of fact. 
First, the attending physician presents the facts in the case, giving, for 
instance, the history of the patient’s condition from the time of receipt of 
the accident, the treatment he received, and his condition as he has gone 
along, up to the time of the trial; that is, he is asked to give all these facts, 
and then, as an expert, too, to give his opinion as to the seriousness of the ac- 
cident, the effect that it has had upon his sufferings up to that time, and also 
his opinion as to the future damages the patient may sustain. The medical 
experts on both sides are also asked to testify as to the existing conditions Medical Expert Testimony. 
8 
they found upon examination ; and there is one thing particularly noteworthy, 
namely, that in all these questions of fact as to the condition of the patient 
we find the expert witnesses practically agreeing. When one leg measures 
in length two inches more than the other, or is that less in diameter, when one 
knee is swollen to twice the size of the other, a joint anchylosed, muscles 
atrophied, limbs distorted and tendon reflexes impaired, we never see, on 
the part of these experts, a disagreement as to the existence and extent of 
these injuries; that is, it is especially important to note the substantial agree- 
ment that we always find in all these things. In short, the palpable, per-, 
ceptible facts of the case are always stated with the utmost fairness. 
There is never any disagreement in the testimony of the experts between 
one side and the other. The attending physician, in spite of all the sympathy 
and interest that he has in his patient, as you will note, is very faithful in 
his testimony as to these patent facts in the case. 
But the moment the scope of inquiry changes from the lesions which the 
patient presents, and which are patent to our eyes and our touch, and passes 
on to matters of opinion, then wide differences become apparent. Not only 
will the opinions oftentimes be very different but absolutely conflicting. It is 
simply that the witnesses have passed from a field of exact knowledge into 
one more or less involved in conjecture and theory. For instance, the plain- 
tiff may come before the experts presenting no physical signs of injury what- 
ever. There has been no injury of a limb; no scar of any wound on the 
body ; no evidence of any injury of the spinal column ; no paresis of any 
muscles; no fault of tendon reflexes; in short, no lesion upon which we can 
place our fingers. Still, the patient has received a fall, or a concussion; 
shows anemia, a lowered vitality, complains of severe headaches, loss of 
memory, fault of vision, pains in the back, weakness of muscles, loss of sleep, 
and numerous other symptoms (frequently inconsistent with each other) that 
the neurasthenic often presents. To the one physician, this imaginary patient 
of mine presents a typical case of concussion of the spinal cord. He is per- 
fectly certain that such an accident is possible and that it has happened in this 
case, and he may even go so far as to believe and explain that at the time of 
the accident there occurred a disturbance of the ultimate molecules of the 
spinal cord, and that the present condition of the patient is absolutely typical 
of such an accident, and that her future recovery is a matter of very great 
doubt. Believing this, he will probably go on and explain to the jury that 
this aforesaid disturbance of the ultimate molecules has actually occurred, 
and if he believes this theory at all he will be very certain of the correct- 
ness of it, although, of course, there is not one iota of evidence that such 
a thing did occur, or ever can. While to another expert, this same pa- 
tient, without the slightest evidence, from the crown of her head to the soles 
of her feet, of having ever received any injury, so far as her physical ex- 
amination goes, presents simply the type of the hysterical woman, and, in 
view of the circumstances surrounding the case, in his mind is probably a 
malingerer. 4 
Medical Expert Testimony. 
Between these extreme and irreconcilable opinions as to the character of 
the case will be presented perhaps as many others as there are different 
men to express them, the latter less radical, but as inconsistent with each 
other as the two that I have indicated. As we candidly and impartially con- 
sider this case, no one of us would doubt for a moment that this conflicting 
and irreconcilable testimony was given by the various medical experts per- 
fectly honestly and conscientiously. In fact, these differences of opinion, so 
far as they show anything, tend to establish the absolute good faith and 
integrity of the witnesses, and really, who in the world can say, in the midst 
of these differences, where the truth lies ? Is there_any diagnostician among 
us of such wisdom and such experience that he can aid the jury in elucidating 
the exact truth ? While it is very desirable to the cause of justice that this 
snarled skein of fact and theory should be unravelled and the truth separ- 
ated from the error, yet there is no source from which this assistance can 
come. The fact is that justice is asking an exact opinion from a very inexact 
science, and the medical experts have given all of knowledge they have and 
all of theory that they have constructed to elucidate the complex condi- 
tions that surround the case. They have simply given the best they had, and 
that is very far from any precise conclusions. 
In support of my contention, a very eminent lawyer and judge of New 
Hampshire, with many years of experience in court and on the bench, ex- 
presses himself in the following terms : 
“ This bias, or inclination, in favor of the party by whom the witness is 
employed is probably the most frequent complaint of all against the expert 
witness, and the inclination, or partiality, is often characterized by terms in- 
dicating dishonesty and corruption. But it is my belief, resulting from the 
observation and experience of many years, that there are few instances in 
which the scientific witness permits himself to testify, or to be engaged on a 
side contrary to his convictions derived from a careful examination of the 
case.” 
I suppose another cause for these irreconcilable differences of opinion may 
be found in the mental characteristics of physicians, themselves, as a class. 
For the most part, they are men of strong convictions. They are much in the 
habit, in the absence of exact knowledge, of framing theories and tracing back 
causes from effects, or following out effects from causes. An endless field of 
speculation is presented to them in the study of the influence of the mental and 
moral conditions upon physical disturbances, but most of all in the study of the 
functional deviations of the nervous system from the standard of health. This 
opens a very wide field for speculation and theory, which is very little guided 
by actual and precise knowledge. Physicians are, therefore, very prone to 
form all sorts of theories, and, when once formed, they adhere to them with a 
pertinacity that would even do credit to members of the clerical profession. 
Hence, when we descend to the practical arena of the court room, these pet 
theories of ours are sure to come out and stand forth in clashing inconsistency 
with each other, and the strict honesty of the experts simply emphasizes the Medical Expert Testimony. 
5 
contradictions that appear. It is just this condition of things that is com- 
plained of in the matter of medical expert testimony. 
Now, is it certain that the cause of justice would be promoted if we could 
all agree in our theories instead of having different ones ? Is it at all certain 
that an agreed theory would bring the jury any nearer to a just appreciation 
of the case than they have now reached in sifting the conflicting testimony as 
it has been presented? It is true that this condition of things is unsatisfactory 
to court, lawyers and physicians themselves, but is there any remedy for it ? 
It seems to me that the character of the testimony asked for and the character- 
istics of the men giving it make these differences inherent and irremediable. 
A supposed remedy, however, has been suggested, and that is that in the trial 
of these causes the judge should appoint some disinterested and capable expert 
to testify in the case, while allowing the litigants to call their respective ex- 
pert witnesses, as is now done. This course of procedure seems to me to be 
open to some very grave objections. In the first place, we have no reason to 
suppose that the physician, or surgeon, so selected, would be markedly more 
competent than other experts who would be employed, while the known fact 
that he was thus selected to instruct the jury would give his theories in the 
case almost the weight of judicial authority. Yet, as a matter of fact, he 
would be quite as likely to be wrong in his theories and conjectures as the 
other experts employed. So, while he might further the cause of justice, there 
would still be a very great danger, on account of the weight of authority that 
would thus be given his opinions, that he might work far greater injustice to 
either defendant or plaintiff than would be the case with the present procedure. 
That is, simply his official position in the court would give to his opinions a 
weight and importance that could in no way justly attach to them. Were it 
possible to select a single man so markedly above his confreres in experience 
and ability that his testimony in a given case would be entitled to the greater 
authority the court would give him this selection might be a remedy for the 
difficulties we are considering. If the man selected were not superior in abil- 
ity and judgment to his confreres in the case his testimony would acquire a 
fictitious and unjust importance. Therefore, I believe that the selection of 
such an expert in such a manner would be a hindrance to the cause of justice 
rather than a remedy to the conditions complained of. For the best selection 
possible of such an expert to be made, it would have to be made by our pro- 
fession. When made by the judge it is a selection of a layman, so far as the 
medical profession is concerned, and it would be just as absurd, in case some 
lawyer were to be appointed to the bench, to leave the selection of that lawyer 
to medical men as it would be to have a member of the legal profession, even 
if he were a judge, select the most competent expert from among physicians. 
Now, personally, if I were going into court asking justice for some injury re- 
ceived, I would go about among my professional brethren and select those ex- 
perts who entertained the same opinion as to the extent of my injuries, the 
amount of damage I had received and was going to suffer, as I believed my- 
self, and I would call these men as medical experts. On the other hand, I 6 
Medical Expert Testimony. 
should expect the defendant corporation to select those experts who enter- 
tained the view of my condition that accorded with theirs, who, in short, be- 
lieved exactly as they did, and we would present our case before the jury. I 
certainly should seriously object to an expert employed by the court testifying 
in this case of mine, simply because I should feel that his testimony would 
acquire a weight and importance to which the ability of the man would not 
entitle it, and I believe that the jury, listening to the testimony of my experts 
on the one side and that of the defendant corporation on the other, would be 
more likely to reach a just conclusion in the case without, rather than with, 
the assistance of the court expert. 
In conclusion, I will say that in this matter of the employment of expert 
testimony Ido not believe there is so very much to correct. I hold that the 
great mass of medical experts, which includes our entire profession, are con- 
scientious and honest, with very rare exceptions, in the evidence they give, 
and that, so far as the testimony of experts in regard to fact is concerned, they 
always agree, and in so far as their testimony is an expression of opinions, 
they will often very widely disagree, and there is no remedy for that. And 
whatever improvement the future may have in store for this kind of evidence 
must simply come through the medical profession itself. The greater ad- 
vances we make in science, the greater our ability, the better we understand 
the laws that govern the mental, moral and physical natures of our being, the 
less erratic and the more uniform and reconcilable our theories will become. 
And outside of this advancement there is no remedy for the faults of medical 
expert testimony, if to any great extent such difficulties now exist.