HISTOLOGY OF INFLAMMATION.
INFLAMMATIONS of the various tissues assume different forms as far
as the gross appearances are concerned, but the underlying condition
is precisely the same. The various types of inflammations that are
produced by one and the same process are of considerable scientific
interest, but to the practical and inquiring reader, whose principal
object is to obtain sufficient information to be able to cure herself,
it would be confusing were I to attempt a description of their
differences.
There is no word that is so often employed as _inflammation_, as a
designation of disease, and when we learn that there is only one kind
of inflammatory process, whether of the brain, the lungs, liver,
kidneys or bowels, the entire subject of inflammatory diseases at once
becomes greatly simplified, because if you understand one you must
understand all.
I will in the subsequent chapters speak only, or principally, of
inflammatory affections of the different organs that come within the
province of this specialty, and I am convinced that if the reader will
bear with me, so that I may take sufficient time and space to explain
the most advanced scientific views of inflammatory processes, she will
be more than compensated, by a clearer understanding of what will be
said in succeeding pages.
Inflammation comprises a series of phenomena, which partly take place
in the vascular apparatus or blood vessels and partly in the tissues
comprising the structure of the organ. Inasmuch as inflammation is
not a single process, a definition of a few words is insufficient to
convey to the mind its real meaning. If I were simply to describe the
peculiarities of the circulation, that characterize the inflammatory
process, we should only have an incomplete idea of the changes that
were taking place.
Since the time of Galen, who lived two hundred years after Christ,
_inflammation_ was recognized by four cardinal symptoms, namely
redness (RUBER), _swelling_ (TUMOR), _pain_ (DOLOR) and the increased
temperature (CALOR). To these modern pathologists have added a fifth
symptom, which is lessened or diminished function (FUNCTIO LÆSA).
The above five cardinal symptoms can be established in the majority of
the acute stages of inflammation: in the chronic or subacute variety,
one or the other symptom may be absent, or so obscured as to escape
notice.
The nature and structure of the tissue materially modify some symptoms
and exclude others, so that redness, pain and even perceptible swelling
may be absent. Galen already in his time attributed the redness to an
increased blood supply and the swelling to an exudation of lymph or
serum, through the walls of the blood vessels: this was as near the
truth as scientists arrived, until within our own time. The discoveries
in this field of science have been greatly enriched in the last twenty
years through the researches of the German school. Various theories
have been advanced from time to time, as to the probable causes or
processes that are going on in the tissues while inflammation is
active. One observer believed that he had found the solution of the
inquiry in a supposed spasmodic contraction of the capillary blood
vessels, another in their paralysis, while still another adhered to the
belief of a neurotic affection. Professor Virchow, the father of the
modern school of pathological science, ascribed the conditions of the
tissues to an irritable state of the inflammatory process, inducing an
exaggerated cell growth; while his former pupil, Cohnheim, through an
extended series of newly-devised experiments, has conclusively proved
that none of the theories advanced are supported by demonstrable facts.
Our present thorough knowledge of the combined disturbances and
phenomena, that play their part in the vessels and tissues, of the
body during the inflammatory action in living tissue is due to the
unremitting toil of Professor Cohnheim. He was the first to speak from
facts, as they presented themselves to his eye under the microscope. It
was he who had the genius that suggested the examination of the whole
process of inflammation, in the living tissues under the microscope.
This he accomplished by narcotizing a frog, and while alive, but
insensible to pain, a portion of the peritoneum or mesentery, which
is almost transparent, so that the circulation may be plainly seen,
was fastened with pins upon an ingeniously-devised rack or stage. The
inflammation is now excited by etching the membrane with a little acid
and a sharp needle, and then the object is placed under the microscope.
If the operator is careful, so as not to tear or crush the vessels
or tissues, and preserves the moisture, by spraying with warm water
from time to time, the circulation and the abnormal processes of
inflammation that are going on, may be observed and studied with great
exactness for several hours. I will now describe what may be seen in
the field of the microscope.
The first change to be observed is in the vascular system and within
the vessels themselves; this begins with a widening of the small
arteries, then of the smaller capillaries and veins. This increases the
current of blood with greater velocity through the widened vessels.
Sooner or later this rapidity of the current lessens; there is a
marked slowness to be observed in the stream. The single or separate
blood cells, which in the beginning of the observation could not be
distinguished, can now be distinctly seen, especially in the veins and
small capillaries, in which, from the slowness of the current, the
blood accumulates. In the veins there now appears at the periphery
of the current a pellucid plasmatic layer, in which there are white
blood cells, that have separated themselves from the main current; the
white cells either float slowly along or adhere to the walls of the
vessels. This phenomenon the Germans term “Randstellung der Farblosen
Blut Körperchen,” which means, bordering of white blood corpuscles.
Not long after the “bordering” of white cells, a change takes place in
the cells themselves, that is very interesting. The white cells become
elongated and spear-shaped at one extremity, which pierces the wall of
the vessel, and after a little while the sharp extremities will appear
on the outer surface of the wall of the vessel, and a little later
on, indeed, the entire protoplasmic cell will have emigrated into the
tissue, outside of the vessel. Or, in other words, the colorless blood
cells will have passed through the walls of the vein or capillary, and
this constitutes an _extravasation_.
The first extravasated cells will soon be followed by others in great
quantity, so that in six to eight hours veins and capillaries are
surrounded with white corpuscles. In their normal destination these
become organized into fibrous or granulation tissue; and for this
reason, an organ that is the seat of chronic inflammation becomes
immensely enlarged from this inflammatory accretion. We can now readily
appreciate why the womb, liver or kidneys become augmented in size from
inflammatory processes. Indeed, this applies to all growths and even
to bone, and if a part is injured by a cut, accident or disease of
some sort, precisely the same processes are at work to repair the lost
tissue. It cannot fail to become apparent at once, that to understand
the phenomena of inflammation is to possess the key that opens to
our understanding the operations not only of most diseases, but of
the healing processes of wounds and injuries. In the course of the
experiment we see also red blood corpuscles transude, which are always
accompanied with more or less fluid or plasma.
The above detailed account seems to explain in a clear manner the
different cardinal symptoms that have become recognized features of
inflammation since the time of Galen. The great vascular activity
explains the redness, swelling and increased temperature. The pain can
be traced to the pressure from the exudation, to which the delicate
nerve filaments were exposed, while lessened function would be the
natural result of nerves or tissues so compromised.
I made an attempt to initiate the reader into the science of
inflammatory processes and if I have succeeded in making myself
understood, then I am satisfied with having imparted a most useful
lesson, because there is no process in the entire field of disease that
is so general; it is almost safe to say that with the exception of
functional diseases, there is perhaps no class of diseases with which
an inflammatory process is not more or less associated. This is true
of consumption, which is an inflammatory process excited by and around
the bacilli or micro-organisms, and these inflammatory nodules are
called tubercles. The growth of a cancerous tumor is associated with an
inflammation. The development of a common boil is an illustration of
an inflammation, breaking down or destroying part of the tissue which
is inflamed. It is the same in inflammation of the lungs or pneumonia
as it is in ordinary catarrh; the differences that are presented to
the eye are only modifications of degree and peculiarities that are
due to the difference of the tissues of which the organ or membrane is
composed.