awakening from this lethargy began to show themselves. The first steps,
naturally, were along preparatory lines, and for those we are largely
indebted to the physicists, the chemists, and the botanists. Gross
anatomy became better known, owing for the most part to more enlightened
legislation on the subject of the dissection of the human body; minute
anatomy (histology) sprang into existence as the result of improvements
of the compound microscope. Physiology took on something of the
experimental; and medication was rendered far less gross and repulsive
by the isolation of the active principles of medicinal plants. But it
was long after all this that the telling strides were taken. Up to
within the memory of many men who are now living, "peritonitis" tortured
its victims to death, said "peritonitis" being often interpreted as a
manifestation of rheumatism, for example, and no well-directed
interposition was attempted against it, whereas we now know perfectly
well that the vast majority of cases of peritonitis are due to local
septic poisoning and for the most part quite readily remediable by the
removal (with a minimum of danger) of the organ from which such
poisoning arises--almost always the vermiform appendix. "Appendicitis,"
of which we hear so much nowadays, is no new disease; it is simply the
"peritonitis" that killed so many people in former times. But while no
well-informed person would now maintain that this disease was a new one,
there are many, and those, too, among the best instructed, who find it
difficult to avoid the conclusion that, if not new, it must at least be
of far more frequent occurrence than formerly. It must be borne in mind,
however, that in the great majority of instances in past years it ended
spontaneously in recovery and was forgotten.
Two features of the progress in medicine in the Nineteenth Century,
negative as they may seem to have been, were undoubtedly potent in the
promotion of advance. They were the recognition of the fact that many
dangerous diseases are self-limited, and the experiment of the so-called
"expectant treatment." The result of the first of them was to teach men
to desist from futile attempts to _cure_ the self-limited diseases, in
the sense of cutting them short in their course, and the "expectant
treatment" followed as a natural consequence. It was a method of
managing disease rather than attempting to cure it. There was no
interference save to promote the patient's comfort, to nourish him as
thoroughly as might be without unduly taxing his powers, and to meet
complications as they arose. It was stooping to conquer, perhaps, but it
was a policy that conduced greatly to the well-being of the sick,
improved their chances of recovery, and enabled physicians to study
disease more accurately by reason of its course not being rendered
irregular by meddlesome medication. It has never been dropped, and it
never will be, save as such directly curative agents as the antitoxines
are made available.
In the early part of the century, except for gross anatomy and operative
surgery, medicine was taught almost wholly, so far as the schools were
concerned, by means of didactic lectures. The "drawing" capacity of a
professor was proportionate rather to his rhetorical powers and to the
persuasiveness with which he inculcated the views peculiar to himself
than to the amount of real information that he conveyed to the students.
Although the apprentice system--for that was what the practice of
students' attaching themselves to individual practitioners, whom they
called their preceptors, virtually amounted to--in many instances made
up more or less completely for the lack of systematic clinical teaching,
yet in the great majority of cases it amounted to little more than the
preceptor's allowing the student the use of his library and occasionally
examining into the latter's diligence and intelligence, in return for
which he, the preceptor, required an annual fee and exacted from the
student such minor services as his proficiency enabled him to render. It
is true the students "walked" the hospitals, drinking in some great
man's utterances, but they did it in droves, not a moiety of them being
able to get a good look at a patient, unless it was such a passing
glance as might tell them that the patient was jaundiced. By clinical
teaching we understand teaching, not in glittering generalities, but in
the concrete, either at the bedside, as the word _clinical_ originally
implied, or at least with the patient actually present to illustrate in
his person the professor's descriptions and the success or failure of
the treatment employed. The clinic is now firmly established, and has
been for years, but it was long before this grand result was attained.
Experimental methods of study gradually came into vogue, particularly in
the domain of physiology. In this sphere Dr. William Beaumont, of the
United States Army, was a pioneer. His historic experiments on Alexis
St. Martin, a soldier who had been wounded in the stomach and recovered
with a permanent opening into that organ, will ever rank among the most
important of the early experimental studies of digestion. It was not
long before Claude Bernard extended similar inquiries to the other
functions of the body, notably those of the nervous system; and since
his time there has been a long array of brilliant investigators of
physiology and of other branches of science tributary to medicine.
Experiments on living animals were almost the only means of carrying on
these researches. In the early days the animals employed were doubtless
put to a great deal of pain--perhaps in many instances to unnecessary
suffering--and an altogether laudable feeling of humanity has led good
people to band themselves together for the purpose of putting a stop to
vivisection, or at least of greatly restricting the practice and of
freeing it from all avoidable infliction of pain. These praiseworthy
efforts have in some instances been carried so far, unfortunately, as to
seriously hamper scientific investigation--investigation which has for
its object the alleviation of human suffering and the saving of human
life. We may earnestly deprecate and strive to prevent wanton
reiteration of painful experiments for purposes of demonstrating anew
that which is unquestioned, and we may resort to all possible means to
render necessary experiments free from actual pain (from the anguish of
trepidation we can seldom relieve the poor animals), but let us not
block the wheels of scientific progress.
At the dawn of the Nineteenth Century, to examine a sick person's
pulse, to inspect his tongue, to observe his breathing, to interrogate
his skin by our sense of touch, and to try to make his statements and
those of his friends fit in with some tenable theory of the nature of
his ailment, were about all we could do. Possibly it was because he
realized to an uncommon degree the tremendous impediment of this narrow
limitation that Samuel Hahnemann, the founder of Homoeopathy, cut the
Gordian knot in sheer rebelliousness, and proclaimed, as he virtually
did, that a diagnosis was not necessary to the successful treatment of
disease, but that one only needed to know empirically how to subdue
symptoms, meaning mainly, if not solely, what we term "subjective"
symptoms--those of which the patient complains, as opposed to those that
we ourselves discover. But the physical examination of the sick, before
extremely meagre in its sphere and restricted in its possibilities, was
destined to expand before many years into the minute and positive
physical diagnosis of the present day.
In the year 1816 a French physician, Réné Théophile Hyacinthe Laennec,
achieved undying fame by publishing to the world an account of his
labors in the application of mediate auscultation and of percussion to
the diagnosis of the diseases of the chest. It is true that no less a
personage than the "Father of Medicine," Hippocrates, is reputed to have
practised succussion as a means of diagnosis; that is, the shaking of a
patient, as one would shake a cask, to ascertain by the occurrence or
non-occurrence of a splashing sound if the person's pleural cavity was
distended partly with water and partly with air. It is probable that
Hippocrates and many others after him carried the physical examination
of the chest still further, for it is difficult to imagine, for example,
that so simple a device as that of thumping a partition to make out the
situation of a joist by the sound evoked should not early have been
applied to the human chest. But, be this as it may, to Laennec belongs
the great credit of having laid a substantial foundation for the
physical diagnosis of the present time, and, more than for laying a
foundation, for constructing a fairly complete edifice. He who should
now undertake to practise general medicine without having first made
himself proficient in the detection and interpretation of the sounds
elicited by auscultation and percussion in diseases of the heart and
lungs would foredoom himself to failure.
It was not until many years later, early in the second half of the
century, that the clinical thermometer came into general use, but it
soon showed most strikingly the superiority of the "instrument of
precision" to the unaided senses of man. Who would think now of trying
to estimate the height of a fever by laying his hand on the patient's
skin, or who, even among the laity, would be satisfied with such a
procedure? "Doubtless," said the present writer in a former publication
("New York Medical Journal," Dec. 29, 1900), "the use of the thermometer
has occasionally given rise to needless alarm, but almost invariably it
may be interpreted with great certainty. Often it dispels unnecessary
anxiety as in a twinkling by its negative indication, and surely it is
to be credited with being distinctly diagnostic in those diseases of
which it has itself established the 'curve.'" By the thermometric
"curve" of a disease is understood the general visual impression made by
the graphic chart of a temperature record--the course of a zigzag line
connecting the points indicated by the various individual observations.
Numerous other instruments of precision are now in constant use, among
the most wonderful of which perhaps is the ophthalmoscope, whereby we
are enabled to subject the retina and the intervening media of the eye
to minute visual examination. There is not an organ of the body that is
not now interrogated daily in the way of physical diagnosis, and we even
examine separately the secretion of each of the two kidneys. In
addition, there are multitudinous specific signs of which we were not
long ago in complete ignorance. To cite only one of these, there is
Widal's agglutination test, by which the bacteriologist can usually make
a diagnosis of typhoid fever far in advance of the time at which it
could otherwise be distinguished. The use of the Röntgen rays in
diagnosis was one of the crowning achievements of the century, and now
we seem about to enter upon a course of their successful employment in
the treatment of disease--even some forms of cancer--as well as in its
detection.
Beyond the vermin that infest the skin and the hair, tapeworm, and a few
other intestinal worms, little if anything was known of morbific
parasites before the Nineteenth Century; but the labors of Van Beneden,
Küchenmeister, Cobbold, Manson, Laveran, and others have now established
the causal relationship between great numbers of animal parasites--gross
and microscopic--and certain definite morbid states. This has led to a
great increase in our knowledge of the connection between the parasites
of the lower animals and grave disease in human beings, and on this
knowledge rest many of the precautions that we are now able to take
against the spread of such disease. From the consideration of animal
parasites as the direct causes of disease, we naturally come to the
contemplation of the subject of insects as the carriers of disease. The
later years of the century have witnessed the demonstration of the fly's
agency in the transmission of malignant pustule and typhoid fever, and
that of certain mosquitoes in the conveyance of yellow fever and
malarial disease. We now know that bad air (the original meaning of the
word _malaria_) has nothing to do with fever and ague, and that swamps
are not unwholesome if they are free from infected mosquitoes. The
mosquito does not originate the malarial infection; it simply serves as
the temporary host of the micro-organism (_Plasmodium malarioe_) which
is the cause of the disease, having obtained its transient "guest" from
some human being. Consequently, marshy districts that are full of
mosquitoes are not malarious unless the mosquitoes are of the kinds
capable of lodging the plasmodium, and unless there is or has recently
been present in the neighborhood some person affected with malarial
disease. Moreover, the most virulently malarious region is a safe place
of residence for human beings, provided they protect themselves
absolutely against the bite of the mosquito. This has been strikingly
demonstrated in the case of the Roman Campagna.
From the disease-producing animal parasites we come now to those that
are believed to be of vegetable nature. Under the general name of
_bacteria_, there are multitudes of micro-organisms having pathogenic
powers, each giving rise to some definite specific disease, and certain
associations of different bacteria causing particular morbid conditions.
Generations ago physicians had a glimmering of what we now term the germ
theory of disease, as was shown by their use of such expressions as
_materies morbi_ and morbid poisons. Even the definite relationship of
special microscopic organisms to individual diseases was foreshadowed by
Salisbury nearly fifty years ago. But it was not until years after those
conceptions, and in no wise descended from or led up to by them, that an
intelligible and satisfactory germ theory of disease was formulated.
It is to Pasteur, the immortal chemist, that we owe this theory, as well
as that of the attenuation of viruses--both of more than theoretical
import, since they have given us aseptic surgery, the power of
frequently preventing hydrophobia, the antitoxine treatment of
diphtheria, and the ability to stay the hand of Death in the form of
many a stalking pestilence. Every infectious disease is now held to be
due to its own particular micro-organism, and many diseases that were
not until recently thought to be infectious are now classed as such
because they have been proved to be caused by living germs. Conspicuous
among these diseases is pulmonary consumption. In the case of almost
every one of these diseases we have discovered the specific germ and are
able to demonstrate its presence, either by its microscopical
appearance, by its behavior on contact with certain stains, or by the
forms that cultures of it assume. The micro-organism of small-pox and
that of cancer (the existence of which is assumed) have not yet been
isolated. Some of these germs, like that of tetanus (lockjaw), gain
entrance to the system only through a wound; others, like those of
typhoid fever and cholera, are swallowed; others, like that of
pneumonia, are inhaled; still others, like that of tuberculous disease,
are either swallowed or inhaled. Some are believed to be transmissible
to the unborn child; and a few are ordinarily harmless parasites,
becoming pathogenic only when they accidentally gain access to other
parts of the system than those which constitute their natural habitat.
These microscopic organisms do not by their mere presence set up
disease, unless indeed they are in such overwhelming numbers as to block
the capillary blood vessels mechanically. Some of them are carried
broadcast in the blood current, while others remain at the point of
entrance; in either case they elaborate certain products, termed
toxines, which act, either locally or through the circulation, to cause
the disease. These toxines eventually kill the micro-organisms that
produced them, quite as an animal may be smothered in its own
exhalations; or at least they would do so if the "host" survived long
enough for the completion of the process. Meantime, they have either
killed the "host" or been defeated by certain very interesting natural
processes. But before either of these occurrences has had time to take
place, fortunately, in the great majority of instances, save those of
exposure to the most deadly of infections, the vital power of the
invaded individual has coped successfully with the invaders at the very
point of attack--has repulsed the attacking party without appreciable
impairment of its own force--and no illness results. For example,
practically all of us inhale the germ of consumption repeatedly, but
most of us suffer no harm from it simply because the fluids which bathe
the surface on which the germ effects a lodgment are endowed with
properties which either kill the germ or rob it of its power for harm;
but these properties suffice only when the general health is unimpaired.
In case the attack is not successfully repelled at the outset, what
happens? There begins a struggle between the invaders and what may be
called the reserves of the organism, consisting of the white blood
corpuscles, which undergo a great augmentation in number. These
corpuscles are endowed with the faculty of amoeboid movement; that is to
say, they may shoot out projections from their substance, and even
convert themselves for the time being into traps, seizing upon the
pathogenic bacteria, incarcerating them within their own mass, and
carrying them away to be thrust out of the system by organs whose
function it is to eliminate extraneous matter. These corpuscles are,
indeed, said figuratively to _eat_ the malign micro-organisms, whence
they have been termed phagocytes (from [Greek: phagein], to eat, and
[Greek: kutos], a cell); also because they carry away refuse and
noxious material, they have been called "the scavengers of the system."
By means of their amoeboid movement they are enabled to worm themselves
through inconceivably minute apertures in the blood vessels, and attack
and devour peccant matter wherever it may have effected a lodgment.
These white corpuscles are also known as leucocytes, and their increase
in number when they are called upon to resist bacterial invasion is
spoken of as hyperleucocytosis. The discovery of their protective
function is to be credited to Metchnikoff, a Russian physician now
teaching in Paris. When they migrate from the blood vessels in great
numbers they finally, after having fulfilled their office as phagocytes,
degenerate into the corpuscular elements of pus, which is the creamy
liquid contained in an abscess. Their migratory power was discovered
by Cohnheim.
But as a general thing the phagocytes do not succeed in making away with
all the pathogenic germs, or even with enough of them to prevent the
illness which they tend to produce. The further combat is between the
poisonous products, termed toxines, engendered by the bacteria and
certain antidotal substances, called antitoxines, newly created in the
watery portion of the blood by some wonderful provision of Nature that
is not yet well understood. Each infective disease has its special
toxine, and for the destruction of each the blood prepares its
particular antitoxine; possibly, however, some of the antitoxines may be
efficacious against more than one kind of toxine, for there are
physicians who are convinced that vaccination is a temporary preventive
of whooping-cough. But the elaboration of an antitoxine takes time, and
the result in any given case, whether in recovery or in death, seems to
be settled by the ability or inability of the vital powers of the
individual to hold out until they are relieved by the evolution of the
necessary amount of antitoxine.
In the long run, provided the sick person survives, more antitoxine is
generated than is required to save life. The excess remains in the
system for a greater or lesser length of time, and this fact explains
the individual's subsequent immunity to the disease from which he has
recovered; any fresh invading force of the microbes of that disease
finds that defensive preparations have been made in advance. In the case
of some diseases this acquired immunity is usually lifelong, as in that
of small-pox; in others, of which influenza is a notable example, it is
as a rule very transitory; and there are all gradations between the two.
It is thought that this acquired immunity to some diseases may be
transmitted to the offspring, for it is quite certain that there are
many people who are from birth insusceptible to scarlet fever, no matter
what may be the extent of their exposure to that disease.
The recognition of Nature's elaboration of protective antitoxines has
led to their artificial cultivation in the lower animals, and, thus
produced, they have been used with brilliant results in the prevention
and cure of at least one formidable disease, diphtheria. The immense
reduction of the mortality from this disease that has followed the
introduction of the treatment with the artificial antitoxine we owe to
Behring, of Germany, and Roux, of France. Omitting unnecessary details,
we may describe the process of obtaining diphtheria antitoxine as
follows: A certain amount of diphtheritic poison (of the bacteriological
sort, prepared by cultivating the diphtheria microbe) is injected into
the circulation of a horse--sufficient to make the horse sick, but not
enough to endanger his life. The horse's system straightway begins to
elaborate the protective antitoxine, and there results from this one
injection a sufficient amount of it to save the horse, although far too
little to make the serum of his blood potent enough for medicinal use.
Hence, after the lapse of a suitable interval, he is again injected with
diphtheritic poison, and for the second time his blood begins to
generate the antitoxine. And the process is repeated again and again,
the virulence of the poison being increased each time, until the horse's
blood is fairly reeking with antitoxine. Then blood is drawn freely from
the horse, and it is allowed to separate into clot and serum, the
latter alone being the part destined for use. This serum is tested on a
small animal that has been inoculated with a deadly dose of the
diphtheritic poison; if it saves the little creature from death, it is
assumed to be potent enough for use on human beings, and, handled with
all possible precautions against putrefaction or any contamination with
pathogenic bacteria, it is furnished to physicians, its degree of
potency being designated in "units."
If in this brief article, which does not purport to be more than a
sketch of the tremendous strides made by medicine in the Nineteenth
Century, so much space has been given to the germ theory of disease, it
is because the demonstration of the truth of that theory has been
absolute, and has constituted the very marrow of almost all the medical
progress of the century that has been the outcome of continuous thought
and study as opposed to chance discovery.
Such results as the germ theory has now led to in the treatment of
diphtheria it had already accomplished in the field of surgery as a
consequence of that strict asepticism which, originating with Joseph
Lister (now Lord Lister), and rapidly carried by him to a condition
verging on technical completeness, was soon taken up by surgeons all
over the world and brought wellnigh to perfection, so that the mortality
of wounds of all sorts has been tremendously reduced, and many surgical
operations are now practised frequently--indeed, whenever the occasion
for them arises--that before the days of Listerism would have been
looked upon as almost tantamount to the patient's death-warrant. More
particularly is this the case as to operations which involve opening
into the abdomen, the chest, or the cranium. So little risk now attaches
to such operations, properly performed, that the opening of the
abdominal cavity for the mere purpose of ascertaining the condition of
its contents--"exploratory laparotomy," as it is called--is a matter of
constant occurrence. Curiously enough, in some way not yet
satisfactorily explained, that procedure in itself, without anything
further being done, has in many instances resulted in decided
amelioration of a morbid condition, if not in its cure. A striking
example of this is seen in the benefit that often results in cases of
one form of "consumption of the bowels," namely, tuberculous disease of
the membrane that lines the abdominal wall and invests the abdominal
organs. This is not the only operation that does good mysteriously; that
of cutting out a bit of the iris in a form of deep-seated eye disease,
glaucoma, that tends toward complete blindness, is hardly more
explicable; neither is an incision of the capsule of the kidney for
certain forms of Bright's disease, each of which stays the progress of
the trouble in a goodly proportion of instances.