The Nobel Prize in Physiology or Medicine 1904
Ivan Pavlov
Presentation Speech by Professor the Count K.A.H. Mörner, Rector of the Royal Caroline Institute, on December 10, 1904
Your Majesty, Your Royal Highnesses, Ladies
and Gentlemen.
The medical sciences are mutually interdependent. Progress in one
field is often closely associated with development in others. The
rise in one branch of science can often have its origin in a
recently made analysis within another sphere, and yet it may
appear at the first glance that the former is of outstanding
importance while the latter is apparently of secondary value. It
is not always such progress, as immediately are useful and
of benefit, which should be considered as especially important;
this character can also be attributed to those which are
themselves less spectacular but form the basis for the others
which are then only a further development of it.
The aim of science is the acquisition of knowledge, the value of
which should not be measured by the ease with which it can be
brought immediately into practical usefulness. Examples of this
can be seen in various accounts of scientific developments which
have given their originators a prominent place in the history of
Medicine. One may point to Vesalius and Harvey. When Vesalius, in
spite of the personal risks to which he exposed himself, through
his masterly researches opened the way to the study of human
anatomy, he was impelled by his desire to carry the torch of
science through the covering veil of prejudice and authoritarian
belie£ When Harvey through long years of investigations and
deep study was able to prove the circulation of the blood, it was
his thirst for truth which spurred him on in his work; to satisfy
it was his reward.
The importance of the activities of these men for the whole of
Medical Science must be estimated from the contributions they
gave to the advancement of knowledge - from the view which thus
became established in these sciences and has stimulated them to
new and vigorous development. It would be a very unjust
underestimation of them, if they were judged by the
immediate value of their work.
The man, whose magnificent intentions established the Nobel
Foundation was not unfamiliar with or averse to the aims and
achievements of scientific research. This can be seen from the
fact that his directions about the medical Nobel Prize linked it
with physiology. The study by the physiological sciences of
normal life processes and associated problems is in most cases of
a purely scientific nature and however important the results of
research may be in themselves, it is only exceptionally and in a
roundabout way that they emerge into practical use. The questions
of the investigator to Nature and the yearning which fires his
desire are directed in the first instance to the gaining of new
and deeper knowledge. Other factors also show that Nobel greatly
appreciated investigators who were seeking knowledge for its own
sake without considering other circumstances.
The medical Nobel Prize has this year been bestowed upon a man
whose activity falls within the theoretical branches of the
medical sciences, namely, the Professor in the Military Medical
Academy of St. Petersburg, I. P. Pavlov, for his work on the
physiology of digestion.
In the early days opinions on the course of digestion were
speculations as to what was termed as «cooking» or
«grinding» in the stomach etc. So long as the digestive
processes could not be observed or investigated directly in the
stomach no real knowledge could be obtained. An accident turned
physiological research in this field in a direction which has
later become very important. In the 1820's a young man sustained
a gunshot wound in the stomach and developed a gastric fistula
which to some extent permitted the gastric processes to be
studied. Observations were carried out on this man by the
American physician W. Beaumont. This accidental path of
investigation, allowing actual observation of processes taking
place in the digestive tract, was later followed by many workers
using animals. Technique is an important factor in such
experiments and has been perfected in a masterly way by Pavlov,
whose animals remain in good health, without any injury to the
function of their digestive tract, permitting observation and
systematic investigation over an almost unlimited period.
These methods for the study of the physiology of digestion
established by Pavlov have been taken up by various physiological
institutions, but above all much important work was performed in
his own laboratory. From this has followed a far-reaching
transformation of our knowledge in this field which has also been
enriched by new fundamental facts.
The following may be mentioned as an illustration.
The digestive canal can be influenced in various ways by the
nervous system. When we remember that the nervous system can
induce not only the secretory processes as well as the movements
of various parts of the system, but also can bring such processes
to a standstill, that it controls the blood supply to these
organs and that sensory nerves arise from them, we can get an
idea of the complexity one encounters. The complications become
still greater when it is realised that we must take into account
not only nervous pathways having their origin in the brain or the
spinal cord, but also the sympathetic nervous system, and that we
have further to pay attention to the interdependence between the
different parts of the digestive system through the nerves, so
that variations in the behaviour of one may affect that in other
organs.
It is in the nature of things that cognition of the scope and
character of the functional interdependence of the nervous system
and the digestive organs is of great importance to the knowledge
of the physiology of these organs. It is also clear that one can
only hope that answers to these complicated questions will
advance step by step by much research. In this respect Pavlov has
acquired very great merit. He has revealed new points of view and
has fruitfully stimulated the solution of these problems, and
through his methods has made it possible to reach conclusive
analysis of them.
Before Pavlov, knowledge in this field was in many respects very
imperfect. Pavlov has corrected earlier erroneous opinions which
were held even with regard to the main points within this part of
physiology. He has further enriched it with significant
data.
The detailed description of digestive physiology, to which we are
indebted to Pavlov lies outside the scope of this presentation. I
can therefore not go deeper into what we owe him with regard to
the physiology of the salivary glands, nor the clarification
which he has provided of the motor functions of different parts
of the intestinal tract, such as the stomach, gallbladder etc.
Valuable though these investigations are, I must content myself
with merely mentioning them here.
Nevertheless, I will briefly sketch his far-reaching work on the
physiology of gastric secretion.
It is well known that ingested food undergoes chemical and
physical alterations under the influence of the secretion from
the mucous membrane lining the stomach. The secretion of the
gastric juice and the recognition of its constituents is of great
importance to the normal utilization of the foodstuffs. An
elucidation of the circumstances which are significant in this
respect therefore gives important information about the
physiology, and thus also the pathology, of digestion.
Before Pavlov's work it was the general opinion that the gastric
secretion was not influenced via the nerves connecting the
stomach and the central nervous system. This conception has,
however, been shown to be incorrect. Pavlov has demonstrated that
the vagus nerve linking the brain with various thoracic and
abdominal organs contains fibres which during their activity
stimulate gastric secretion and others which have an exactly
opposite effect. In this way the secretion of gastric juice is
controlled by the central nervous system and can be influenced
from different parts of the body. It has also been found that by
this means the gastric secretion is influenced by psychic
impressions and impulses.
In this connection I will mention that Pavlov has enriched our
knowledge of the significance and functions of this important
nerve in other respects also. The vagus nerve paths are not, it
appears, the only stimulators of gastric secretion. Pavlov has
shown that it may also be influenced through the sympathetic
nervous system.
Pavlov has also demonstrated another aspect of the functional
association between the gastric mucous membrane and the nervous
system, in the specific excitability of the mucous
membrane itself. Before the work of Pavlov it was supposed that
it could be brought into activity by almost anything within the
stomach. Purely mechanical contact was considered to have this
effect. Pavlov demonstrated, however, that this generally
accepted view was incorrect. The reverse is true, the gastric
mucous membrane having a sharply differentiated excitability for
special substances with which it comes into contact. Thus there
are relationships reminiscent of the specific excitability of the
sense organs.
The eye is sensitive to light rays of such weak intensity that
they do not exert any influence on other parts of the body.
Similarly, the hearing organs are affected by vibrations in the
air. Corresponding processes are observed in the other sense
organs; they show a quite special sensitivity to certain unique
stimulators.
It is now known, thanks to Pavlov, that a similar specific
excitability is present in the mucous membrane lining the
digestive tract, even though the subject is not conscious of it,
and it acts by influencing the processes of secretion and of
motility of the canal. This mucous membrane has in fact a unique
faculty of being stimulated by certain substances present in the
food or otherwise present in the digestive tract. Many other
substances - among them some which in small amounts may exert a
marked or even strong effect on the sense of taste or on the skin
- have no or comparatively little stimulating action on secretion
when they come into contact with the gastric mucosa. Still other
substances exercise an inhibiting influence on the gastric
secretion.
As another aspect of this specific sensitivity of the gastric
mucous membrane one must consider the remarkable fact,
demonstrated by Pavlov, that the amount of gastric secretion and
its digestive strength show certain typical variations dependent
upon the quality of the food taken.
I have so far only given a short survey of Pavlov's contributions
to the knowledge of the physiology of gastric secretion and
indicated a few other aspects of the physiology of the stomach
about which he has enlightened us. His work also encompasses
other digestive organs, in some of which he has found analogies
with the stomach. In yet others he has observed differences
between various organs. Also this work has been extremely
important from several points of view but to delve more deeply
would take us to far.
Pavlov's researches into the physiology of the digestive organs
constitute a systematic series of experiments in order to shed
light on this field from different angles. He thus seeks to
investigate associated problems apart from those directly
connected with the innervation of the digestive organs; problems
related to the active constituents of the digestive fluids, thus
questions of a purely chemical nature, have also been studied.
Here Pavlov has given new points of view and impulses which
constitute very valuable contributions to this field. Since,
however, our knowledge of the substances concerned - the
so-called ferments - is still wrapped in many respects in
obscurity in spite of the careful work of many previous
investigators, I will only quote one fact, first known
through Pavlov's investigations. I refer to his extremely
interesting observation that a certain ferment or more correctly
a ferment-producing substance in the pancreatic juice acquires
the qualities which permit its activity during digestion only
after being influenced by another ferment which occurs in the
intestinal juice.
In this we find a kind of chemical co-operation between various
digestive organs. This combination has even more facets, and
other forms of mutual organ-activity have been described by
Pavlov. He has not only studied the isolated physiology of the
different digestive organs but also the whole system which they
constitute together. It can be said that the observations he has
made converge to what he has called the «efficiency of the
work of the digestive tract», by which he means the organic
correlations between its different parts. Through Pavlov's work
we have obtained a much more extensive and clearer insight than
our previous knowledge could give us. We have now a fairly
comprehensive view of the influence which the activity of one
portion of the digestive apparatus can exert on another; in other
words how the wheels of the digestive mechanism fit together for
the efficient use and advantage of the body.
If the mechanism becomes disordered, the situation can be
changed, and such conditions falling within the field of
pathology, have also been successfully studied by Pavlov by the
methods introduced by him.
Already Pavlov's work on digestion has been found to be of great
importance for the study of disease, and undoubtedly the progress
made in physiological knowledge in this case as well as in others
will lead to a transformation of the concept of diseases and
their treatment. How great such a change will be remains so far
uncertain. But this is on this occasion a question of secondary
importance, for it is for his revolutionary and reorganizing work
on the physiology of the digestive apparatus that the Staff of
Professors of the Caroline Institute has conferred on Professor
I.P. Pavlov this year's Nobel Prize in physiology or
medicine.
Ivan Petrovich. I have just announced that the Staff of Professors of the Caroline Institute has bestowed upon you the Nobel Prize in Physiology or Medicine for your work on the physiology of digestion. I hereby give you the congratulations of our Institute on the contribution you have made to the development to Physiology and the profound transformation which you have made in an extremely important region of that science.
From Nobel Lectures, Physiology or Medicine 1901-1921, Elsevier Publishing Company, Amsterdam, 1967
Copyright © The Nobel Foundation 1904
We are currently working on the web site. Please report errors or problems.
