EXPERIMENTS 
WITH 
LIVING HUMAN BEINGS.’ 
By GEORGE M. BEARD, M. D. " 
[Reprinted from The Popular Science Monthly, March and April, 1879.] 
I. 
MR, JOHN STUART MILL, in the preface to his work on “Logic 
and the Principles of Evidence,” observes that while in the 
search for truth we may be able, in some cases, to avoid errors in- 
stinctively and successfully, although unable to formulate the method 
by which we do so, yet it is an advantage not to be dispensed with 
to have a rational understanding of the philosophy of reasoning, so that 
we shall not be forced to depend alone on blind and irregular instinct. 
In experimenting with living human beings there are six sources of 
errors wdiich instinctively phj'siologists and physicians sometimes guard 
against and allow for, but which ought to be and can be, as I contend,, 
and shall here aim to prove, reduced to a positive science. As these 
elements of error come in the main from the nervous system, their 
study belongs preeminently to neurology, or the study of the nervous 
system in health and disease ; and it is because of the backwardness 
of this specialty that the subject has been thus far passed by. 
The deficiencies of our knowledge of this subject were forced on 
1 An abstract of a portion of this paper was read before the American Neurological 
Association at New York, June, ISYS. This essay relates to questions suggested in my 
series of papers on “ The Scientific Study of Human Testimony,” published in the May, 
June, and July (1S78) numbers of the “Monthly,” and may be of service to those who are 
interested in that subject. This department of science is of especial interest at the pres- 
ent time, Avhen the experiments of Charcot and the criticisms upon them are exciting so 
much attention. 2 
my attention several years ago, when I was engaged in the study of the 
physiology of mind-reading, and making experiments in mental thera- 
peutics ; and in essays published on those topics I briefly noted these 
errors, which I was obliged to study out,- and without any theoretical 
guide or precedent. I found that the whole matter—the importance 
and interest of which were of the very highest, practically as well as 
scientifically—was as unexplored as central Africa, and that it was 
necessary to hew one’s way clear of infinite obstructions at every 
step. 
From the elevation of this subject to a positive science these three 
practical benefits must flow : 
1. The world will be spared the reports of such experiments as those 
of the physician who examined into the condition of the hysterical girls 
that were the cause of the Salem witchcraft epidemic, and of the com- 
mittees of the French Academy, of Gregory and of Elliotson and others, 
with clairvoyance and mesmeric trance; of Crookes with Home, of 
Wallace and Zollner with Slade, and, latest of all, of Parkhurst and 
others with Mollie Fancher; of Charcot, Westphal, and their coadju- 
tors with metalloscopy and metal-therapeutics; and will at the same 
time be able to reach the solid truth that lies behind all such accredited 
phenomena. These experiments and these reports are often made by 
strong and earnest men ; indeed, the abler the experimenter in the 
present state of the subject, the worse his experiments and his reports 
of these experiments : instead of arriving at the truth of many ques- 
tions of physiology, we get farther and farther from it the more we 
study them. 
2. There will be more precision to all our investigations in regard 
to the action of remedies, and especially of new remedies. At the 
present time we know not whether to believe or reject any report of 
the virtues of any’ new medicine or mode of treatment, how’ever high 
the authority for the reports, for we feel instinctively the elements of 
error which those who introduce new remedies and modes of treatment 
ought to know, and in time will know and rationally provide for. 
3. Men of narrow or but limited ability will be able to attain accu- 
rate results in experimenting with living human beings where now 
the strongest scientific geniuses of the world are every day failing 
abjectly and humiliatingly. Sir William Hamilton, in his work on 
“ Logic,” remarks most truly that the proud boast of Bacon that, by 
the system of inductive philosophy, it would be possible for ordinary 
men to make discoveries in science, has been strictly fulfilled : every 
day under the light of the inductive method very commonplace minds 
are finding new and important facts that go to swell the current of sci- 
ence. Genius of the first order is rare, and in every field of knowledge 
the details of cultivation must be worked out by the average man ; the 
bulk of the work is done, always has been done, and probably always 
will be done, by talent rather than by genius. 3 
The elements of error in experimenting with inanimate objects 
were indicated, in a general way, by Bacon, under the strange headings 
“Idols of the Tribe,” “Of the Den,” “Of the Forum,” “ Of the The- 
atre”; and later writers on evidence and the principles of science have 
repeated or assumed the Baconian formulas ; but the special elements 
of error in experimenting with living human beings have escaped con- 
scious and exhaustive analysis. To have formulated these elements of 
error much sooner than the present time would have been quite impos- 
sible, for our knowledge of the involuntary life—one of the most im- 
portant factors—was far too limited. 
The science and art of experimenting with living human beings is 
indeed now in precisely the same state as the general philosophy of in- 
duction prior to the time of Bacon. Before the era of the Baconian 
philosophy, indeed in all eras, men had instinctively employed the in- 
ductive method, but the principles of that method had never been for- 
mulated ; consequently, when philosophers reasoned or attempted to 
reason on the subject, they almost always went wrong. The philosophy 
of Bacon applies only to inanimate nature; of the art of seeking truth 
through experiments on living human beings—of the six sources of 
error in all such experiments and the means of guarding against them 
—he knew nothing, and evidently suspected nothing; and that branch 
of philosophy—of such vast import in biological investigations—has re- 
mained to this day unstudied and almost unthought of; hence, although 
some experimenters are saved through their instincts, others—and those 
the very ablest scientific geniuses of the age—never attempt to reason 
on the subject without falling into serious error. 
In experimenting with living human beings there are, as above 
stated, just six sources of error, all of which are to be recognized and 
systematically and, if possible, also simultaneously guarded against if 
our results are to command the confidence and homage of science. To 
be guilty of overlooking, in any research, even one of these six possi- 
bilities of error, is to be guilty of overlooking all, and practically to 
vitiate all the results of our labors. 
These six sources of error are as follows : 
First Source of Error: The phenomena of the involuntary life 
in both the experimenter and the subject experimented on.—Under this 
head are embraced trance, with all its manifold symptoms, and all the 
interactions of mind and body that are below the plane of volition or 
of consciousness or of both. Without a knowledge of this side of 
physiology, scientific experimenting with living human beings is impos- 
sible. It is a want of this knowledge that makes most of the experi- 
ments of scientific men in this department during the past century so 
unsatisfactory and so ludicrous. 
Second Source of Error ; Unconscious deception on the part 
of the subject experimented on.—This unconscious deception comes 4 
through the involuntary life—the mind of the subject acting on the 
body—and producing results which, it is to be noted, are as decided, as 
uniform, and as permanent as when produced by powerful objective 
influences. This element of error slips into all the ordinary experi- 
ments with new remedies and supposed new forces in the animal body, 
thus corrupting science at its very sources. The neglect of this 
element of error would of itself, even though all the other errors were 
guarded against, destroy entirely the scientific value of all such experi- 
ments, for example, as those of the committees of the French Academy 
with clairvoyants and mesmerism ; it is because physicians of experi- 
ence instinctively feel this element of error, that reports of cases 
wrought by novel and strange and especially by imposing methods of 
treatment are so frequently discredited. Under this head come also 
all the so-styled miracles of healing, whatever may be the paraphernalia 
through which they are accomplished. 
I know not where can be found a better single illustration of the 
effect of this element of error, alone of itself, in scientific research, 
when all the other elements of error seem to be provided for, than in 
the experiments on animal magnetism of the late Dr. J. K. Mitchell, as 
recorded in the volume of his miscellaneous writings. Dr. Mitchell 
was an original thinker, an observer of patience and care, and a clear 
and logical writer, who suggested more than he told, and his chapter on 
animal magnetism was incomparably the best essay ever written on that 
subject down to the date of its publication. This paper—which con- 
sisted of a record of independent, careful, and many times repeated 
experiments on living human beings, with remarks thereon—shows that 
the author not only had the courage and the powder to do his own think- 
ing and experimenting, but that he recognized some of the chances of 
error in experiments of this kind, and fortified himself against them ; 
while of the errors that enter through the doors of the involuntary life— 
the unconscious deception of the subject experimented on—he knew, 
and apparently suspected, little. His essay is therefore at once a 
model and a warning: a model for thoroughness and precision up to a 
certain point, or within a limited area ; a warning as demonstrating the 
worthlessness of all experiments with human beings when any one or 
two of the six sources of mistake are overlooked. So accurate and 
scientific were these experiments, in certain directions, that they have 
furnished an important contribution to our knowledge of some of the 
symptoms of mesmerism, in spite of the fact that the author failed, 
like hundreds of able men in science before him, to solve the problem 
of the nature of trance. By not understanding and taking into account 
the phenomena of the involuntary life, of which in his day very little 
was known, and of trance, of which nothing was known, this acute and 
philosophic observer allowed the subjects on whom he operated to con- 
stantly deceive themselves and deceive him, and to drive him to the 
logical but absolutely false conclusion that the mesmeric trance was an 5 
objective state induced by a supposed fluid, or force, or influence, tben 
and now known as animal magnetism. 
In order to be able always to guard effectively and absolutely against 
these two sources o£ error that I have thus far specified, just two things 
are necessary for the experimenter : 
1. A general knowledge of the phenomena of the involuntary 
life, including both the action of mind on body and of body on mind, in 
health and in disease, and especially of the real nature and philosophy 
of trance, the state in which the involuntary life culminates. 
2. The subject experimented on must always be deceived in the 
experiments in such a way that this involuntary action of his mind 
or bod}' can not come in and destroj7 the experiment. The subject may 
be successfully deceived in three different ways, which I shall presently 
specify. 
Burq, Charcot, Westphal, and their coadjutors in the now well-known 
metalloscopy experiments, failed on both of these points. Many of the 
critics of those experiments, as Althaus, Reynolds, and other physicians 
in England, also failed to comprehend these points, hence the incon- 
sistency and unsatisfactoriness of the discussions to which these experi- 
ments gave rise. The claim of Burq and Charcot and Westphal in 
regard to the temporary relief of hysterical and sometimes of organic 
anaesthesia by the local application of metals might be entirely true, but 
thus far they have failed, in a scientific sense, to prove it to be true. 
I do not deny their results—indeed, there is a possibility that some of 
them may be genuine—although in my own experience with the same 
method I fail to confirm their claims; it is in the manner in which the 
experiments were conducted, without regard to the results, that the non- 
expertness of these experimenters appeared. The criticism I have to 
make on Charcot is that, in his elaborate lectures on this subject, he 
nowhere gives evidence of a full appreciation of the power of the 
involuntary life, particularly in hysterical conditions, or of the true and 
only method of systematically and successfully guarding against it. 
The experiments now going on under the same superintendence in the 
hospital of Salpetriere with mesmeric trance, and with the effects of 
magnets and lights on catalepsy and kindred conditions, are all open to 
the same criticism. 
If some savage fresh from the jungles were put on board of an 
engine, and told how to open the valves, he might very naturally infer 
that his own feeble strength caused the train to move ; in like man- 
ner, scientific experimenters with living human beings attribute the 
phenomena that follow the application of metals and magnets and 
passes and flummeries soleß to the objective influence of these appli- 
ances, whereas in truth these and similar performances but serve to let 
on the potent forces of the subject’s own mind. The mistake of these 
philosophers is indeed quite analogous to that of the little boy who, 6 
when placed on the front seat of the carriage, pleases himself with the 
fancy that he is guiding the horse, when all the time his strong father 
behind him is quietly holding and pulling the reins. In all experiments 
with living human beings, as in the special branch that we call thera- 
peutics, it is oftentimes not what we do, but how we do it, that deter- 
mines the results. 
As regards this first point—the action of mind on body—I may say 
that, by a series of experiments not yet published, but a brief abstract 
of which has been twice presented to this Association, it has been 
proved that, by properly turning the mind of the patient on his body, 
through excitations of the emotions of wonder and special expectation, 
it is possible not only to relieve for the time various functional dis- 
eases, but in many instances to perfectly and permanently cure them; 
and it was also shown that organic or structural diseases may be 
relieved in the same way, in some cases, more satisfactorily than by any 
objective medical treatment whatever. The method by which the emo- 
tions are to be acted upon for the purposes of mental therapeutics are 
now so far organized into a science that any one who will make himself 
practically familiar with the subject can obtain the same results. The 
first mistake of Charcot and his coadjutors in France, and his followers 
in England and in Germany, was in assuming that such effects as the 
orderly, uniform reappearance of the sense of the different colors in 
hysterical women, and the symmetrical transference of sensory phe- 
nomena from one side of the body to the other, under the local appli- 
cation of metallic disks in hemiansesthesia, could not be produced 
subjectively by the mind of the patient. Such an assumption would 
never have been made by any one who had performed or witnessed the 
experiments in mental therapeutics of which I have spoken ; for, again 
and again, not cnly in hysteria, but in other forms of disease, and in 
conditions not distinctively nervous, I have obtained results which, in 
definiteness, in quantity, and in permanence, are far more imposing, 
proving beyond question that, when all the sources of error were con- 
sidered and provided for, the results were entirely independent of any 
objective power in the means employed—were, in short, subjective 
purely ; applications of metals, or wood, or paper, or no applications at 
all, provided the subject expected them, being equally effective. 
Science is not a matter of opinion ; its very essence is demonstra- 
tion ; and the question whether, in any given experiments, the results 
are subjective or objective, can be brought entirely out of all discussion 
and all opinion, provided the elements of error are understood and 
avoided. Indeed, all discussion in scientific matters must be, in logical 
strictness, unscientific: if we know anything, there may be need for 
statement, of explanation, of illustration, but nonq for discussion ; if we 
do not know, the course of wisdom is to keep silence until we do. 
With the formulated six sources of error before them, and the methods 
of protecting themselves against them, the experiments of Charcot 7 
would never have been discussed, even for a moment, in any scientific 
body. 
The three methods of deceiving the subject by which alone the 
element of error from mind acting on body can be eliminated, and the 
results of experiments with living human beings transferred from the 
realm of opinion to science or positive knowledge, are these : 
1. By doing something when the subject experimented on believes 
that we are doing nothing. 
2. By doing nothing when the subject believes that we are doing 
something. 
3. By doing something different from what the subject believes is 
being done. 
In experiments of importance, as where radical and overwhelming 
discoveries in science are claimed to be made, all of these methods of 
deceiving should be used ; and it is because they are not used in the 
experiments of scientific men that we are constantly compelled to face 
and listen to the claims of “ animal magnetism,” of “ odic force,” of 
“spiritism,” of “cundurango,” of “blue glass,” and, during the past 
year, of “ Mollie Fancher,” of “ metalloscopy,” and “ metal-therapeu- 
tics.” 
A classical example of one method of deception in experiments of 
this character was afforded by the expose of the performances of mes- 
merized or professedly mesmerized girls by Mr. Wakley, of the Lon- 
don “ Lancet.” A good example of neglect of this deception, as well 
as of ignorance of the relation of mind to body, is found in the experi- 
ments of Dr. Vansant with magnets, as published by him a few years 
ago. This writer gives an immense number of differential symptoms 
that, as he claims, are produced by the north and south poles of the 
magnet; his experiments were in the same line with the famous Per- 
kins tractors, though apparently more scientific ; the same criticism 
applies to the researches that are now being made in the Salpetriere 
Hospital in Paris, where, according to the testimony of experts who 
have witnessed them, and the statements of the experimenters them- 
selves, no systematic deception is employed or even suggested. 
That even the strongest leaders in physiology are not fully armed 
against the errors that beset experimental research, when living human 
beings are the subjects, is shown in the not long ago published Lowell 
Lectures of Professor Brown-Sequard, wherein that master in experi- 
mental study through the processes of vivisection declares that the 
claims of telling of time through the back of the head are authentic. 
Deductive reasoning for ever disproves this claim, which any inductive 
research, properly conducted, must always confirm ; but any test to be 
of value must, at every step, shut out absolutely all the six avenues of 
error ; and the report of any te§t, in order to be worth reading, must 
clearly state and show that all such errors were so excluded. 8 
Experiments in physics are likewise, in some instances, conrplicated 
with experiments with living human beings. Thus in the “ Keely 
motor ” and “ Winter motor ” claims, and in other like devices for the 
overthrow of the law of the conservation of energy, the apparatus for 
generating power was in the hands of interested non-experts, who 
might be capable of either willful or self-deception—for the purposes of 
science it matters not which—and no satisfactory experiment could be 
made unless these possibilities of error could be eliminated. 
The temporary success of cundurango was almost entirely the re- 
sult of self-deception of those who, under the mingled emotions of hope, 
despair, and expectation, availed themselves of it. It is impossible to 
introduce any drug or system of treatment for cancer, or any other 
grave disorder, amid great pomp and noise, and under the patronage 
of honored names, without at least relieving, for the time, a certain 
proportion of cases ; and practically it is of little import what the drug 
or remedy may be, if only the confidence of the sufferers is assured. 
Men not only of general but of special experimental ability are con- 
stantly going far out of the way in scientific research through want of 
simple knowledge of the laws and phenomena of the involuntary life— 
a branch of physiology which, though of extreme interest and overflow- 
ing in suggestion, is so young and recent in its development that it is 
not yet taught in colleges or schools. The published monographs of 
the late Mr. Braid, of Manchester, show indisputably that their author 
was not without a certain genius for scientific research ; but in all his 
philosophizing on the effects of fixed attention and straining of the 
eyes in the production of what has been known as hypnotism he missed 
utterly the discovery, or even the suspicion, of the great fact that 
trance, of which hypnotism is bat one of numberless phases, was a sub- 
jective not an objective condition—existing in the subject’s own brain 
—and that the manoeuvrings by which he was wont to excite it were 
but one of infinite devices for acting upon the mind ; thus Mr, Braid 
failed to solve the problem of trance. Similarly Professor Czermak— 
one of the inventors of the laryngoscope—though he made many ex- 
periments in the production ot liypnotism in animals, likewise con- 
founded the subjective with the objective, and did not arrive at the 
true explanation of his own experiments. Indeed, from the time of 
Mesmer down, all or nearly all the scientific studies and attempted scien- 
tific studies of trance, in any of its multiform phases, have been made 
valueless by this same non-recognition of the involuntary life, of which 
trance is the extreme expression. Confounding the subjective with the 
objective vitiates nearly all human philosophy. 
Similarly Mr. Edison, in his experiments with those highly interest- 
ing phenomena that he supposes to indicate a new force, was so far 
misled by the muscular contractions of the tongue when applied to a 
block of iron, through which the suspected force was passing, as to 
conclude that an objective influence was acting, whereas, after the ele- 9 
ment of error from the expectation of the experimenter was eliminated, 
it was quickly shown that the contractions were entirely subjective, Mr. 
Edison, I may say, is not only an inventor of phenomenal genius, but 
likewise a skilled and practiced experimentalist, and, as I found when 
making these and similar investigations with him, extraordinarily fertile 
in resources of method and device for wresting the secrets from na- 
ture, and usually alert against subtile sources of error ; but, when drawn 
into the province of the involuntary life, he found himself, like men 
of science in general, insufficiently equipped with knowledge to even 
surmise, not to say provide for, the errors that may arise from the un- 
conscious or involuntary action of mind on body. 
In some instances the reverse mistake is made, and phenomena of 
the involuntary life are supposed to be volitional. In the case of the 
“ Maine jumpers ” or so-called “ jumping- Frenchmen ” of Canada and 
the Maine woods—the incredible performances of which I have elsewhere 
described—it had for years been assumed, both by men of science and 
by the lait}7, that the movements were intentional, and within control. 
This conclusion, though most erroneous, was quite a natural one for 
those who have no knowledge of the relation of mind to its physical 
substratum. 
An illustration of the second method of deception—doing nothing 
when the subject supposes we are doing something—is professing to 
apply electricity, putting the electrodes in position, and going through 
the motions, when no current is running, or when the connection is 
broken ; in this way I have several times proved that patients were 
mistaken in inferring that electrical applications injured them; and, 
conversely, I have been able in one striking case to prove that the pa- 
tient was right, and that a certain symptom was temporarily aggravated 
by the application. 
Third Source of Error : Intentional deception on the part of the 
subject.—This element of error is so obvious that it would seem to be 
quite needless to refer to it ; and yet it is constantly overlooked even 
in researches conducted by physiologists. To assume, as is often or 
usually done, that the subject on whom the experiment is made is hon- 
est in his relation to that experiment, because he has a general charac- 
ter for honesty, is always unscientific; and all experiments where such 
assumption is made must be ruled out of science. 
Intentional as well as unintentional deception on the part of the 
subject can only be scientifically met by deception on the part of the 
experimenter. The methods of deceiving already described suffice to 
guard against all deception on the part of the subject, whether inten- 
tional or unintentional. 
It is clear proof of the non-expertness of Zollner, Wallace, Charcot, 
and Westphal, that in their published accounts of experiments with 
living human beings they assumed that, if the subjects were honest, the 10 
results of the experiments must be accepted by science. Scientifically 
it makes no difference whether the subject on whom any such experi- 
ment is performed is honest or dishonest; the experiments are to be 
made without any reference to the moral character of the subject. 
Fourth Source of Error : Unintentional collusion of third par- 
ties.—By third parties are meant audiences, witnesses, bystanders, or 
assistants seen or unseen. 
The best illustration of error from this source is the aid which audi- 
ences in the mind-reading experiments give to the performer by their 
silence, when he wanders away from the object looked for, and by their 
murmurs and applause when he approaches or reaches it. This is quite 
analogous to the cry of “ hot ” or “ cold ” in the game of “ blind-man’s- 
buff.” So natural is it for errors from this cause to enter these inves- 
tigations that I found it necessary, in all my researches in that depart- 
ment, to send all witnesses from the room, or to insist on their being 
absolutely silent, and even motionless, at every stage of the experiments. 
Fifth Source of Error : Intentional collusion of third parties. 
—Under this head comes the aid which assistants, known or unknown, 
designedly give to the subject experimented on. This, in the abstract, 
is one of the more readily suspected of all the six sources of error, but 
in the concrete very difficult to guard against, or even to detect, as is 
so brilliantly illustrated in the conjuring tricks of Houdin and Heller, 
and, it may be added also, in the operations of so-called “ confidence- 
men.” 
The best and most mystifying tricks of illusionists, and sleight-of- 
hand performers of all kinds, are almost always done through some form 
of collusion, the time, and method of which are so artfully arranged that 
only those of unusual acuteness or expert skill can at once detect them. 
The astounding success of clairvoyants and mediums in telling people 
what they already know, but which they suppose can not be known to 
the witch they are consulting, is oftentimes explained by this fifth 
source of error. 
Intentional, deliberate deception, where no money is to be gained by 
deception, is much more common among the better classes than those 
who have not specially studied this subject would be willing to believe : 
it is an instructive fact in the psychology of lying, that some persons 
—usually, though not always, women—whose general character is of the 
highest, are in some special direction absolutely systematically untruthful 
all their lives long. An old merchant of New York once told me that a 
clerk in his employ, trustworthy in all business affairs, exact, scrupulous, 
just, had a habit of telling large stories in regard to what he had seen 
and done so firmly fixed that it was organically impossible for him to 
restrict himself to the facts, and that his statements in regard to matters 
outside of business were worthy of absolutely no credence. 
I was once requested by a valued medical friend to aid him in some 
experiments with a case of alleged sixth sense, or the asserted power of 11 
reading without the use of the eyes. The subject who made the claim 
was a lady of education, culture, and social position, universally and justly 
respected. In answer to the request, I stated that by deductive reason- 
ing it wTas established as firmly as the Copernican theory, or the law of 
the persistence of force, that no human creature could have any such 
power, and that therefore it would be unscientific to investigate any such 
claim ; but as an amusement, and for the sake of determining whether 
the deception was intentional or unintentional, I would suggest and pre- 
pare some tests in which all the six sources of error would be excluded. 
This was done. The tests were of course not taken, but the result of 
the investigation was to demonstrate the interesting psychological fact 
that for years a graceful and agreeable lady had been deceiving not 
only strangers and friends, but even her own husband, by means of the 
very old and familiar “ballot-trick,” and a not especially adroit method 
of performing it. The puzzling cases of starving girls, of invalid clair- 
voyants, of mediumship, that are constantly infesting and astonishing 
civilized society, are in many instances to be similarly explained. The 
“mind-readers” were originally self-deceived, since the physiological 
interpretation of that phenomenon is too complex and profound to be 
suggested, not to say comprehended, by the mass of those who are ac- 
customed to practice that art. But at the present time the public per- 
formers probably understand, in a general way, the philosophy of their 
success, at least enough to know that their claims of a sixth sense are 
baseless. 
Lying, like stealing, may become a passion, and, in like manner also, 
may concentrate all its force in some one direction, for folly as well as 
wisdom has its specialties and hobbies : there is a monomania for de- 
ceiving, where naught is gained save its own gratification ; one who is 
in all other directions honorable and just may become an inebriate of 
falsifying, and be half his days intoxicated thereby. 
11. 
IN experimenting with living human beings, deception, whether vol- 
untary or involuntary, can only be scientifically met by deception ; it 
must be beaten with its own weapons. No experiment of this kind in 
which the results depend in any way on the honesty of the subjects ex- 
perimented on can be of any value in science; and those who assume 
that, because the subjects of these experiments are members of great 
churches, and move in high society, they are therefore incapable of un- 
truth, would do well to resign the task of investigations of this sort to 
those who are better endowed with the scientific sense. Systematic, 
orderly, exhaustive deception, on the part of the experimenter, as here 12 
suggested, will, in ail cases, exclude both intended and unintended de- 
ception on the part of the subject or bystanders. 
Sixth Source of Error : Chance and coincidences.—The subject 
of chance and coincidences seems never to have received the attention 
from men of science that its direct and practical bearings on experiment- 
al research and the principles of evidence would long ago have demand- 
ed. On the mathematical side the philosophy of chance has been inves- 
tigated and discussed by various writers, and with not a little intelligence 
and skill ; but with the effect also of misleading many amateur experi- 
menters and reasoners, who have thereby been tempted to employ mathe- 
matical estimates in departments of science where they are sure to guide 
into error. No forms of error are so erroneous as those that have the 
appearance without the reality of mathematical precision. Of this sort 
are the blunders of those physiologists who, at various times and under 
various guises, have sought to solve physiological problems by experi- 
ments half built up on rigid mathematical calculations, the other half 
having no foundation at all; for the average non-expert observer is awed 
and overpowered by the very sight of figures, and assumes that an 
investigation into which addition, subtraction, and multiplication enter 
must inevitably lead to precise and unerring results, forgetting that, as 
quantitative truth is of all forms of truth the most absolute and satis- 
fying, so quantitative error is of all forms of error the most complete 
and illusory. Figures, to be of any value in science, must go all around 
the subject and thoroughly embrace it, else they fail to master it and 
become its possessor : for, while the truth is apparently shut in on one 
side, it is all the time stealthily escaping at the other. Thus it is that 
the most acute calculators, most logical reasoners, and most accurate 
observers as well, are so often cheated out of the truths to the search 
for which their lives are devoted; the instincts of the plow-boy often 
outstripping the wisdom of the philosopher. 
Among this class of scientific blunders is the custom of applying 
the calculations of chances to experiments with living human beings. 
Thus in the now well-known mind-reading performances it was averred 
that by a mathematical calculation there would be but one chance in 
several hundred thousand of finding any object in a house or hall or 
assemblage ; hence it was inferred that a new force, or manifestation of 
force, had been revealed to the world. The fallacies in this philosophy 
do not require a very long search ; of the many objects in any house, or 
indeed in any public building, but a small minority would be accessible 
in any mind-reading test, and of these few only a limited number are 
of a sufficiently positive nature and description to be thought of by the 
subject of such experiments ; then, in addition, are all the errors that 
come from intentional and unintentional assistance of audiences and by- 
standers. 
Practically the only way to eliminate, in a scientific manner, the 
error of chance or coincidence in all experiments of that, character, is by 13 
making comparative experiments in the same line, with all the sources 
of error closed except chance, and to repeat these a sufficient number 
of times to make an absolute demonstration. In this way it was shown 
that mind-reading, so called, was really muscle-reading. In these and 
in all studies of like character it is to be recognized that coincidences 
of the most extraordinary and astonishing nature are liable to occur at 
any instant, and that they are as likely to occur on the first trial as on 
the last of a long series. To determine whether any conjunction of 
events is simple coincidence, or the result of some new fact or law in 
science, is possible oftentimes only through a series of comparative ex- 
periments. In the researches which I made in muscle-reading it was 
shown over and over that by pure chance alone—every other element 
of error being excluded—the blindfold subject would, under certain 
conditions, find the object looked for in one case and sometimes in two 
cases out of twelve. 
It would seem that the errors from chance and coincidence were the 
most patent of all the errors that complicate and confound scientific in- 
vestigation, and so clear even to the unskilled and unthinking mind, that 
trained investigators would never be deluded by 7 them. But in practice 
it vitiates the research and the philosophizing of educated men, even more 
perhaps than any other of the six, excepting the involuntary action of 
mind on body which, as we have seen, has been the stone of stumbling 
for physiologists ever since physiology was introduced into science. 
Hay-fever, for half a century and more, has supplied an unusual 
richness of material for false reasoning of a similar type. An English 
physician, a victim of this disorder, notices that he is worse as he 
crosses a field of grass, and concludes that at last he has found the one 
source of the mystery, and so gives the affection a misleading name 
which it can never lose ; Helmholtz, a leader both in physics and physi- 
ology, puts the nasal secretions under the microscope, discovers some 
unexpected infusoria that are killed by quinine, and announces to the 
world in one breath a theory of the disease and a specific for its cure, 
without apparently suspecting, what is now known, that the presence of 
infusoria might be a coincidence or effect and not a cause. 
To all this it may be said that practically we do find out the true 
value of medicines and their objective action on the human body with- 
out systematically eliminating any of the six elements of error here 
pointed out. This is to be allowed ; but the admission of the fact re- 
quires also an explanation of the way in which these errors are in prac- 
tice actually eliminated, although unintentionally and unsystematically, 
and I may say also, most unscientifically. 
It is by an immense number of experiments or trials on a large vari- 
ety of cases, at different times, by different observers, and under vary- 
ing conditions, that medical science has been able, after centuries of 
doubt and struggle, to arrive at some few real scientific facts in regard 
to the action of medicines. If these six elements of error had, from the 14 
first, been everywhere recognized and comprehended and systematically 
guarded against, the process of finding the truth in this department 
might have been abridged by hundreds of years. The method by which, 
in practice, physicians learn the action of any new remedy, is to give it 
to a number of cases, and then to watch and report the results ; another 
physician repeats the experiments on a different set of cases ; he also 
notes the results: and this process goes on perhaps for years, until in 
lapse of time the profession, without being able to give precise and con- 
vincing reasons for their faith, slowly and instinctively settles down to 
the persuasion that the effects claimed for the remedy are genuine, and 
act accordingly. 
In many instances they are right in this conclusion ; but how awk- 
wardly and in what a roundabout way, and through what useless and 
wearying toil, have they, in doubt and distrust and suspicion, finally 
reached that goal ! All the trials with the remedy, from beginning to 
end, have been impaired in scientitic value by some one or all of the six 
elements of error ; but through the immensity and variety of the experi- 
ments, extending through a long period, these errors have been uncon- 
sciously and unwittingly eliminated, so that only the solid fact is left. 
This unconscious elimination or rather leaving behind of errors, after 
the analogy of the formation of the universe according to the nebular 
hypothesis, takes place in this manner: In the first hundred cases 
treated there will be perhaps one or two, or more, who have no faith in 
and no expectation from it, good or bad ; these few obtain the real ob- 
jective effects of the remedy, while all the others deceive, more or less, 
themselves and their physician. In subsequent experiments by other 
observers, some of whom perhaps are less hopeful than the original inves- 
tigator, the same unconscious and irregular elimination takes place, until 
the objective power of the remedy may for all practical needs be regard- 
ed as established. Such is the history and philosophy of medical experi- 
mentation in all ages and with all schools of medicine I claim that by 
the rigid following out of the principles here taught it will be possible 
for even the humblest member of the profession to take any new remedy, 
and, if a sufficient number of cases be provided, to accurately determine 
some points at least of its therapeutic value, if it really possesses any 
that are capable of being demonstrated to the senses or reason of man. 
It is the unconscious or unformulated apprehension of these errors in 
the working up of remedies that causes so many of the profession to take 
at certain periods of their lives the extreme and unscientific view that 
all medication is a mistake—that drugs have no power outside of the 
mind of the one who takes them—and consequently, and logically, to 
trust only to the forces of nature and hygiene. 
In relation to this branch of our theme, it is worthy of note that 
there are certain modes of treating disease which from the very nature 
and manner of their employment can not be experimented with in a 
truly scientific way ; it is impossible to use them so as to deceive the 15 
patient on whom they are used; of necessity, therefore, they must be 
developed by the process of successive eliminations already described. 
Among the medical procedures of this class are hydro-therapeutics or 
hydropathy, electro-therapeutics, and massage, or systematized rubbing, 
kneading, and manipulation ; none of these remedial operations can be 
used without the patient’s knowledge; none of them can be used in a 
different way from wdiat the patient supposes they are being used ; they 
are open, in clear sight, and affect the various senses so strikingly that 
satisfactory deception is impossible; patients know when they are 
being galvanized or faradized; they know when they are washed or 
showered; they know when they are rubbed and kneaded; no art or 
device of the physician can avail to so deceive them as to absolutely 
eliminate the error that comes from the hope or fear or expectation of 
what the treatment is to accomplish. The practical value of these 
methods of treatment—and they are all of undoubted value—could only 
be ascertained, as it has been ascertained, by the immense variety of 
the experiments that have been made with them, wherein through the 
process of time the six sources of error have been little by little elimi- 
nated. 
In all new remedies and systems of treatment the aim of the scien- 
tific physician should be to make the deception so thorough that what- 
ever effects are obtained must be known positively to be the objective 
action of the treatment or of nature. The criticism which I make on 
Burq, Charcot, and others, who have recently experimented with the 
action of metals of different kinds on the anaesthesia of hysterical pa- 
tients, is that they left the question open when, by a systematic, or- 
derly, and thorough provision against these six sources of error, they 
had it in their power, with the vast material at their command, to have 
absolutely closed it ; if they could not determine with certainty whether 
the temporary disappearance of the anaesthesia on the application of 
plates of copper or silver or.gold was the result of feeble electrical cur- 
rents excited, or of simple mechanical pressure, or of absorption, they 
could surely have answered, to the satisfaction of scientific men, the 
question whether it was to be explained subjectively or objectively; 
but this, through want of appreciation of the sources of error, or from 
want of a formula to guide them in their elimination, they failed to do. 
Even though it should be proved, as it may be, that some of these phe- 
nomena observed by Burq, and Charcot, and Westphal are objective, 
and independent of the expectation of the persons operated on, the 
validity of this criticism is thereby not at all affected. To attempt to 
build up a practice of metal-therapeutics on the basis of metalloscopy 
as that claim now stands, is like putting up a house before we are sure 
of our foundations. The first question to decide is whether metal-thera- 
peutics is or is not really mental-therapeutics. 
In the illustrations for this essay I have chosen, by preference, the 
experiments of scientific men of skill, honor, and distinction, and for 16 
the same reason that Blair, in his work on rhetoric, refers, for examples 
of incorrectness, inelegance, and carelessness of style, only to the writ- 
ings of the greatest masters of style in the language : if these things 
be done in the green trees, what shall be done in those that are utterly 
dry? The average scientist, the every-day physician, the followers, the 
gleaners and popularizers of knowledge, are expected to blunder and 
teach but half truths, if not positive error ; but if all those who should be 
our experts fail us, where can we look for clear ideas ? It is no overplus 
of enthusiasm, no fancy of rhetoric, to say that if these six sources of 
error and the true methods of providing for them had been mastered 
half a century ago, the history of scientific experimenting during that 
time would have been radically different from what it now is. 
On this subject no nation, can throw stones at another ; in all the 
great centers of modern civilization the strongest leaders of science 
and scientific thought have been and are constantly demonstrating their 
non-expertness in the art of experimenting with living human beings ; 
the history of science, or the demonstrably true, and the history of de- 
lusions, or the demonstrably false, run in the same channels ; but in the 
minds of the French there appears to be some psychological peculiarity 
that, while it urges them to undertake, at the same time unfits them 
to succeed in researches of this character, their very genius for sci- 
ence, as it relates to inanimate nature and the lower forms of life, pre- 
disposing them to all error when dealing with living human creatures ; 
hence the paradox of history that France is at once the home of 
science and the home of delusions. Now, for almost a century, the 
ablest philosophers and experimenters of France have been wrest- 
ling with the problem how to experiment with living human beings ; 
from the first committee of the French Academy on mesmerism, 
through Perkinism and Burqism, down to the very latest bulletin of 
Charcot on metalloscopy, it is one uniform, unbroken record of per- 
severing non-expertness and failure : Science constantly baffled, beaten, 
utterly overthrown, yet as often returning to the hopeless contest, 
where delusions always compel a drawn battle, if they do not posi- 
tively win ; experiments without number that have the form of pre- 
cision without its substance ; all truth, or even the suggestions of truth, 
submerged in vast floods of error ; the faith that belongs to religion 
and emotion carried into the realm of science and intellect ; all along 
the line of strong endeavor an obvious want not only of the philosophy 
but even of the instinct of seeking truth from living human beings—in 
the whole history of folly one shall not find a more instructive chapter 
than this; were there no other proof of the limitations of the human 
brain, sufficient could be found in this fruitless searching after truth on 
the part of the most intellectual leaders, of the most intellectual of 
nations, in the most intellectual era of the world. Not only during the 
past year, in the hospital of Salpetriere, but, by recurring intervals, 
during the past century, the best science of France has been on its 17 
knees before hj'sterical women, and there it must remain until it has 
mastered the true philosophy of trance and the involuntary life, and 
learned by heart the sources of error. • 
The time must come when it shall be well understood that experi- 
ments with living human beings, in which the elements of error are un- 
recognized, are not only unscientific but are a satire on science ; bear- 
ing the same relation to the true method of investigation in this special 
department of physiology that the dreams of the mediaeval sages sus- 
tained to the general philosophy of induction. The philosophy of the fu- 
ture will be that the laws of nature are not to be put on the market, and 
can not be bid off at auction, and that the long-standing and unaccepted 
financial prize of the French Academy for the one wbo should prove to 
be endowed with clairvoyant or mind-reading power is as unscientific 
and as puerile as to attempt the bribery of the law of the conservation 
of force, or to hire the sun to rise in the west instead of the east. 
During the past few years it has been my destiny to have been fre- 
quently requested to carry out or to plan for others various experi- 
mental researches with living human beings ; these requests have some- 
times come from professional and scientific men who, in all dealings 
with inanimate objects, are amply competent, both by instinct and by 
reflection, to guard against all illusions and deceptions. It is my hope 
and belief that this formal attempt-ill perfected as it may be—will so 
reduce this subject to a science as to bring it within the power of all 
physiologists to plan and to complete all such experiments for them- 
selves, with ample confidence that the results will invariably be in har- 
mony with the truth. The above analysis, in spite of its necessary con- 
densation, will, it is hoped, make clear even to those who do not follow 
all its details, that in this, as in every other realm of knowledge and 
acquirement, success need not be the result of any special acuteness, or 
cunning, or wusdom, but can be made the possession of any sober and 
well-trained mind that has a sufficient endowment of the scientific sense 
to recognize and submit to the inevitableness of law in all mental as in 
all physical phenomena, and to subordinate, even in scientific research, 
all feeling and emotion to intellect and reason. 
The relation of this subject to delusions is also of much interest, both 
psychological and practical ; during the present century especially the 
prevailing follies of civilization have received an unusual and unpre- 
cedented dignity and strength from the non-expert experiments of sci- 
entific men with living human beings. It is a part of the inconsistency 
of ignorance, and one of the effects of long breathing the atmosphere 
of superstition, that the apostles of the demonstrably false, while they 
uniformly dread and oppose the advance of their natural enemy, organ- 
ized knowledge, yet pray for and welcome all mistakes of scientific men, 
either in experiment or philosophy, as so much addition to their capi- 18 
tal; the weapons with which delusionists of every name prefer to fight 
their battles are forged in scientific armories; trace any one of the rank 
and overrunning superstitions of our day to its utmost radicle, and it 
will surely lead to sources where we are wont to look for light and truth 
—to some great discovery which our chemists, our naturalists, our as- 
tronomers, of fair and noble fame, have evolved, or are believed to have 
evolved, out of experiments that they have made, or tried to make, with 
living human beings; to the laboratory of some physiologist even, who 
forgets that the chief fact in human life is the involuntary life; to some 
logician and philosopher, who has yet to learn that the habit of trusting 
the senses, though endorsed and inculcated in all the universities of the 
world, is the source of half the ignorance and not a little of the suffering 
of mankind.