CLAUDE BERNARD: NEURONS & SYNAPSES

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CLAUDE BERNARD (1818-1878)

Science Issues
Neuro History

C BERNARD

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Claude Bernard was born on 12 July 1813 in Saint-Julien de Villefranche, in the French
region of Beaujolais.

After a first course of private studies, he attended the Jesuits’ colleges of
Villefranche and Thoissey, where he was taught literature but no physics or natural
sciences. Due to family financial problems, he had to abandon his studies and was hired by
a Lyon chemist. At this time he also started an intense literary activity that led first
to the writing of a vaudeville entitled Rose du Rhône and subsequently of a historical
tragedy, Arthur de Bretagne. Determined to pursue his literary ambitions, Bernard moved to
Paris, where he hoped that the editor Saint-Marc Girardin, a fellow Burgundian, would
publish his work. Girardin, however, advised the young dreamer to learn a job: thus
started the career of the man who eventually changed physiology and medicine for ever!
Bernard began medical studies and a few years later he came into contact with François
Magendie and soon became his favourite préparateur (research assistant). He became a medical doctor in 1843, but failed the
examination that would have qualified him to teach in the medical school and was forced to
earn a living in the private laboratory of Dr Theodore-Jules Pelouze, a friend of
Magendie. So that he could continue his reasearch, he married the daughter of a wealthy
woman, Marie-Françoise Martin. From 1847 his scientific life became a continuous
succession of studies, publications and honours.

Bernard’s physiology rests on three conceptual pillars: determinism, the rejection of
teleology and metaphysics, and the overcoming of dependence on anatomy. Bernard inherited
determinism from the two preceding centuries and placed it at the heart of his physiology.
His determinism was “absolute”, first because it concerned both inanimate
objects and living organisms; secondly because a phenomenon will not occur differently
given the same conditions; and thirdly because it also applied to the psychic sphere.
Bernard thus appropriated the teachings of natural sciences and laid the foundations of
much of the subsequent evolution of life sciences. Bernard’s absolute
determinism entailed relinquishing the teleological
and metaphysical tendency of physiology, and transformed it from the science of seeking
the “whys” into that of studying the “hows”. By shrinking the scope of
physiology, Bernard paved the way for the century and a half of extraordinary progress
that so profoundly affected both scientific knowledge and medical practice. The concept
that physiological phenomena depend on physico-chemical causes inevitably entailed the
overcoming of the concept of physiology as “anatomy in motion” (anatomia
animata) and a radical shift in perspective. From these considerations stems Bernard’s
concept of milieu intérieur: he emphasized that an animal’s life depends on the internal
environment, that is, on the plasma (extracellular fluids), which provides the
physico-chemical conditions for the correct functioning of cells. Bernard reasoned that if
correct cell functioning depends on optimal physico-chemical conditions, then these must
be constant and, inevitably, there have to be mechanisms that allow such conditions to be
maintained.

More than sixty years later, Walter Cannon was to broaden this concept and call it
homeostasis.

Since then, a large portion of life sciences has been pivoting on this concept, and it
is difficult to imagine any function of the organism without making reference to
homeostatic mechanisms. In Bernard’s opinion, the “new” life sciences needed to
penetrate the internal environment and investigate its regulation if they were to study
living organisms. To him, this meant animal experimentation (Figure 2). Although animal
experiments had been done since antiquity, Bernard established them as an essential tool
in the acquisition of physiological and clinical data. His conviction that the study of
living creatures is a precondition of understanding the functioning and dysfunction of
organs and organisms influenced generations of scientists and physicians and greatly
contributed towards one of the richest periods in the history of biomedical sciences.

The name of Bernard is inextricably linked to the experimental method, which is
discussed in his well-known Introduction à
l’etude de le médecine experimentale (Figure 3). Although this
association is not entirely correct, and Bernard himself rejected the attribution of its
discovery, it is nonetheless true that he crowned the experience of the two previous
centuries and added two characteristic elements of his epistemological creed: the emphasis
on the concept of hypothesis and fallibilism. According to Bernard, the experimental
method rests on the sequence of events from observation through hypothesis to experiment.
Observation and experiment are not different in nature, but for their position within the
sequence. The experiment is an observation performed with a view to verifying a
hypothesis: by providing facts to the experimenter it becomes in turn an observation (and
the starting point of another sequence). Thus, the logic of experimental reasoning is
circular. Like nobody before him, Bernard emphasized the need for experiments to rest on
experimental reasoning deriving from a hypothesis. But Bernard, educated at the school of
the empiricist François Magendie, knew that a researcher often has to deal with things
about which he knows no “fact” beforehand. In such cases, an “exploratory
experiment” (expérience pour voir) needs to be done. This becomes the starting point
for advancing a hypothesis, which is then subjected to experimental verification. A
fundamental feature of Bernard’s methodological conception is the fallibility of all
theories.

Bernard’s neurological studies have been collected in the Leçons sur la Physiologie et la Pathologie du Système Nerveux (Figure 4), and
in the Leçons sur les Effets des Substances Toxiques et Médicamenteuses. Bernard carried out the bulk of his early neurological studies along the lines
traced by Magendie and shared both Magendie’s experimental approach (ablations, lesions,
use of poisons) and conceptual bases (close bonds with clinical and pathological studies).
An example is his research into recurrent sensitivity: Magendie had observed that pinching
or cutting the ventral roots in dogs resulted in pain-like responses and that resection of
the appropriate dorsal root abolished these responses, a phenomenon for which he coined
the term “recurrent sensitivity” (which seems to depend on unmyelinated fibres
of the ventral root that carry nociceptive information to the dorsal horn through the
dorsal root). Recurrent sensitivity became a popular subject of investigation and
generated many controversies; Bernard performed many experiments on it and resolved its
ostensible contradictions by researching in great detail the experimental conditions
required for its expression.

At least two of Bernard’s neurological contributions have had a crucial influence in
shaping our understanding of the brain’s functions: the emphasis on the role played by the
central nervous system in the regulation of vital functions and the curare studies.

Life and the brain. In his opening lecture of the 1856-1857 Course at the Collège de
France, Bernard stated that he considered the regulation of vital functions (the first
chapter of his Leçons sur la Physiologie et la Pathologie du Système Nerveux) as
the foremost function of the brain. He wrote: “It is [the brain] that activates and
regulates not only all the phenomena of our everyday life, but also influences all the
events of organic life, all the acts related to nourishment, secretion, heat production,
etc . . . There is no longer any doubt today of the truth of this role: in fact, by acting
on the nervous system we can modify not only the actions of everyday life, but also the
phenomena of secretion and thermogenesis; these, though being physico-chemical phenomena,
are closely influenced by the nervous system.” (It was in the course of these
investigations that Bernard noted an appreciable temperature increase in the affected
region following resection of the cervical sympathetic chain: this resulted in the
attribution to him of the discovery of vasomotor fibres, even though his initial
interpretation of this phenomenon was in fact incorrect.) In this context, it is
fascinating to consider that, historically, the relationship between life and nervous
system function has tended to be neglected or considered at best of secondary importance.
However, according to recent theories, it is in the sum of the nervous mechanisms
governing the regulation of the milieu intérieur that neural patterns of functions,
organs and also of body delimitation become organized during evolution (creating the self)
and thus where the origin of consciousness should be sought.

The action of curare. Bernard showed that electrical stimulation
of a motor nerve in a curarized frog does not elicit muscular contractions even if the
muscle is still capable of contracting if stimulated directly; that curare has no action
on sensation; that stimulating a sciatic nerve soaked in curare provokes normal muscular
contraction if the muscle is outside the curare bath, whereas stimulating the sciatic
nerve lying outside the curare bath does not elicit contractions if the muscle is soaked
in the curare bath; and that injection of curare into the artery supplying a muscle (Figure 5) provokes its
paralysis. His numerous curare experiments contributed to the hypothesis that some
structure exists between the nervous motor fibres and the striated muscle fibres with properties differing from those of either.
Bernard had indeed some intuition of the existence of such a structure as he wrote:
“curare must act on the terminal plates of motor nerves” and “Curare does
no more than interrupt something motor which puts the nerve and the muscle into electrical
relationship for movement; “motor” is not quite clear but probably refers to the
activating agent, the one we now call “motor nerve impulse”.

The neuromuscular synapse was eventually described in the early 1860s by a former
student of Bernard’s, W. F. Kühne (1837-1900), and by W. Krause (1833-1910), and more
exhaustively in Kühne’s 1888 Croonian Lecture. By forging new ideas regarding
cell-to-cell communication, as well as by its direct influence, this discovery paved the
way for the foundation of the neuron doctrine and heralded the “synaptic era”.

A little-known article by Bernard entitled Des
Fonctions du Cerveau appeared in the 15 March 1872 issue of the
periodical Revue des Deux Mondes (Figure 6), in which he
elaborated some concepts addressed in his Discours pour la reception in the Académie
Française three years earlier. At variance with many of his Leçons, which are not an
easy read today, Des Fonctions du Cerveau is exceptionally modern in both content and language. In essence, Des fonctions
deals with a refusal to accept the view that thought, intelligence and higher brain
functions are beyond the realm of experimentation. As a physiologist convinced of the
power of experimentation and direct observation, Bernard rejects the idea that brain
function will not yield to experimental research.

Fiorenzo Conti
Istituto di Fisiologia Umana
Facoltà di Medicina e Chirurgia
Università di Ancona
Italy

Favourite Sentences:

1. On determinism:
“To us, physiology is thus the science that aims at studying the phenomena of living
beings and at defining the material conditions that determine their manifestation . . .
once the conditions determining a phenomenon are known, the same phenomenon must be
reproducible by the experimenter at will . . . This is an absolute principle governing
both living organisms and inanimate objects” (Bernard, 1865).

2. On “why” and “how”:
“The nature of our spirit drives us to seek the essence or the reason of
things, so we tend to look farther than the object of our quest . . . Yet, we cannot go
beyond the how, that is to say beyond the near causes or the conditions of the existence
of phenomena . . . What is true is that the nature or the very essence of all phenomena,
be they vital or mineral, will forever remain unknown to us . . . Science has precisely
the privilege of making us know what we ignore, substituting reason and experience to
feeling, and showing clearly the boundaries of our present knowledge. But, by virtue of a
wonderful compensation, as science humbles our pride, it strengthens our power . . . To
sum up, if our feeling daily asks “why”, our reason shows that only
“how” is within our reach; for the present, it is thus only the how that
interests the scientist and the experimenter” (Bernard, 1938).

3. On anatomy:
“Galen performed both
corpse dissections and experiments on live animals, a demonstration that he too perfectly
understood that the former are interesting only insofar as they can be compared with the
latter . . . The humoral or physico-chemical part of physiology, which cannot be dissected
and constitutes what we define as our internal environment has been neglected and
overlooked . . Indeed, when an anatomist observes in a part of the body some muscle
fibres, he concludes that there is muscle contraction; when he observes gland cells he
concludes that there is secretion;when he sees nerve fibres that there is sensitivity and
movement. But how did he learn that muscle fibres contract, gland cells secrete and nerves
are sensory or motor if not by studying living organisms?” (Bernard, 1865).

4. On the constancy of the milieu intérieur:
“The constancy of the internal environment is the element conditioning free,
independent life: the mechanism that makes it possible is in fact the same that ensures
the maintenance in the internal environment of all the conditions required for the life of
the elements” (Bernard, 1878-1879).

5. On the experimental method:
“The complete scientist is one who masters both theory and experimental practice. 1,
he observes a fact; 2, he conceives an idea with reference to this fact; 3, on the basis
of this idea he pursues a line of reasoning, plans an experiment and imagines and
organizes its material conditions; 4, this experiment produces more phenomena that shall
be subjected to observation and so on. In a sense, the scientist’s mind is always between
two observations: one is the starting point of the reasoning, the other its
conclusion” (Bernard, 1865).

6. On the fallibility of
theories:
“The main characteristic that a scientist studying natural phenomena must have is
complete freedom of the spirit based on philosophical doubt . . . When we conceive a
general scientific theory, the one thing of which we can be certain is that – speaking in
absolute terms – all such theories are false. They are but partial and provisional truths
that we need, like steps on which we rest, to advance in our investigation.” And
“If an idea arises, we should not reject it only because it does not agree with the
logical consequences of a dominant theory” (Bernard, 1865).

7. On the experimental medicine:
“I consider hospitals as the anteroom of scientific medicine; they certainly are the
first field of observation for the physician, but the sanctuary of medical science is the
laboratory: it is here that by means of experimental analysis the researcher seeks the
explanations on the nature of vital phenomena in normal and pathological conditions”
(Bernard, 1865).

8. On the brain:
“How can it be that physiologists are able to explain the phenomena that
take place in all of the body’s organs but only a fraction of those that happen in the
brain? It is impossible for such distinctions to exist among the vital phenomena.
Admittedly, these phenomena are endowed with different degrees of complexity, but either
they are all accessible, or they are all inaccessible to our study, and the brain, however
wonderful the metaphysical manifestations of which it is the seat appear to us, can
certainly not be the sole exception” (Bernard, 1872).

9. ” . . . brain physiology must be inferred from anatomical
observations, physiological experiments, and the knowledge of pathological anatomy exactly
like that of all the other body organs.” And, “If we now consider the organic
and physico-chemical conditions essential for life and the
execution of functions, we can see that they are identical in the brain and in all the
other organs” (Bernard, 1872).

10. “Diseases, which ultimately are nothing more than vital
perturbations brought about by nature rather than the hand of the physiologist, affect the
brain according to the common laws of pathology, that is to say, by giving rise to
functional disturbances that are always connected with the nature and the site of the
lesion” (Bernard, 1872).

11. “We believe that the advances of modern science do allow us to
take on the physiology of the brain” (Bernard, 1872).

12. “Physiology demonstrates that, accounting
for the different and more complex nature of the relevant phenomena, the brain is the
organ of intelligence exactly like the heart is the organ of circulation and the larynx is
the organ of voice” (Bernard, 1872).

13. The best:
“I am convinced that when physiology shall be
sufficiently advanced, the poet, the philosopher and the physiologist will understand each
other” (Bernard, 1865).

Bibliography

Bernard, C. (1857) Leçons sur les Effets des Substances Toxiques et Médicamenteuses,
Paris: Baillière.

Bernard, C. (1858) Leçons sur la Physiologie et la Pathologie du Système Nerveux, 2
Vols, Paris: Baillière.

Bernard, C. (1864) Etudes physiologiques sur quelques poisons américains. I. Le
Curare, Revue des Deux Mondes XXXIV (Seconde période), 53: 164-190.

Bernard, C. (1865) Etude sur la physiologie du coeur, Revue des Deux Mondes, 1 mars,
236-252.

Bernard, C. Introduction à l’Etude de la Médecine Expérimentale, Paris: Baillière.

Bernard, C. (1872) Des Fonctions du Cerveau, Revue des Deux Mondes XLII (Seconde
période), 98: 373-385.

Bernard, C. (1878-1879) Leçons sur les Phénomènes de la Vie Communs aux Animaux et
aux Végétaux, 2 Vols, Paris: Baillière.

Bernard, C. (1938) Philosophie: Manuscrit indenit, Paris: Haitier Boivin.

Conti, F. (2001) Claude Bernard: primer of the second biomedical revolution, Nature
Reviews Molecular Cell Biology, 2: 703-708.

Conti, F. (2002) Claude Bernard’s Des Fonctions du Cerveau: An ante litteram manifesto
of the neurosciences? Nature Reviews Neuroscience, 3: 979-985.

Cowan, W. M. & Kandel, E. R. (2001) in W. M. Cowan, T. C. Südhof & C. F.
Stevens (eds), Synapses, Baltimore, The Johns Hopkins University Press, 1-87.

Fessard, A. (1967) in F. Grande, & M. B. Visscher, (eds), Claude Bernard and
Experimental Medicine, New York: Schuman, 105-123.

Grande, F. & Visscher, M. B. (1967) Claude Bernard and Experimental Medicine, New
York: Schuman.

Holmes, F. L. (1974) Claude Bernard and Animal Chemistry: The Emergence of a Scientist,
Cambridge, MA: Harvard University Press.

Lesch, J. E. (1984) Science and Medicine in France: The Emergence of Experimental
Physiology, 1790-1855, Cambridge, MA: Harvard University Press.

Olmsted, J. M. D. & Harris Olmsted, E. (1952) Claude Bernard and the Experimental
Method in Medicine, New York: Schuman.

Shepherd, G. M. (1991) Foundations of the Neuron
Doctrine New York: Oxford University Press.

Claude Bernard (July 12, 1813 – February 10, 1878) was a French physiologist. He was called by Prof. I. Bernard Cohen of
Harvard University, “one of the greatest of all men of science” in his Forward
to the Dover edition (1957) of Bernard’s classic on scientific method, An Introduction to the Study of Experimental Medicine (originally published in 1865).

Life

Bernard was born in the village of Saint-Julien near
Villefranche-sur-Saône. He received his early
education in the Jesuit school of that town, and then proceeded
to the college at Lyon, which, however, he soon left to become
assistant in a druggist’s shop. His leisure hours were devoted to the composition of a vaudeville comedy, and the success it achieved moved him to
attempt a prose drama in five acts, Arthur de Bretagne. At the age of twenty-one he
went to Paris, armed with this play and an introduction to Saint-Marc Girardin, but the critic dissuaded him
from adopting literature as a profession, and urged him rather to take up the study of
medicine. This advice he followed, and in due course became interne at the Hotel Dieu. In this way he was brought into contact with the
great physiologist, François Magendie, who was
physician to the hospital, and whose official ‘preparateur’ at the Collège de France he became in 1841.
In 1845 he married Françoise Marie (Fanny) Martin for
convenience; the marriage was arranged by a colleague and her dowry helped finance his
experiments. In 1847 he was appointed his deputy-professor at the
college, and in 1855 he succeeded him as full professor.

Some time previously Bernard had been chosen the first occupant of the newly-instituted
chair of physiology at the Sorbonne. There no
laboratory was provided for his use, but Louis
Napoleon, after an interview with him in 1864, supplied the
deficiency, at the same time building a laboratory at the Muséum national d’Histoire naturelle
in the Jardin des Plantes, and establishing a
professorship, which Bernard left the Sorbonne to accept in 1868,
the year in which he was admitted a member of the Académie
française. When he died he was accorded a public funeral – an honour which had never
before been bestowed by France on a man of science.

Works

Claude Bernard’s aim, as he stated in his own words, was to
establish scientific method in medicine. He
dismissed many previous misconceptions, took nothing for granted and was relying on
experimentation. Unlike his contemporaries he insisted that all living creatures were also
bound by the same laws as inanimate matter.

Claude Bernard’s first important work was on the functions of the pancreas gland, the juice of which he proved to be of great
significance in the process of digestion; this achievement won him the prize for
experimental physiology from the French Academy
of Sciences. A second investigation – perhaps his most famous was on the glycogenic
function of the liver; in the course of this he was led to the
conclusion, which throws light on the causation of diabetes
mellitus, that the liver, in addition to secreting bile, is the seat of an internal
secretion, by which it prepares sugar at the expense of the elements of the blood passing
through it. A third research resulted in the discovery of the vaso-motor system. While engaged, about 1851, in examining the effects produced in the temperature of
various parts of the body by section of the nerve or nerves belonging to them, he noticed
that division of the cervical sympathetic gave rise to more active circulation and more
forcible pulsation of the arteries in certain parts of the head, and a few months
afterwards he observed that electrical excitation of the upper portion of the divided
nerve had the contrary effect. In this way he
established the existence of vaso-motor nerves, both vaso-dilalator and vaso-constrictor.

Milieu intérieur, internal environment, was the original
concept of Bernard that to this day is of utmost importance. Conditions in the world
around us constantly change, but delicate balance of internal characteristics of our
bodies is not affected. It is achieved through what we call it today homeostasis.

The study of the physiological action of poisons was also a favourite one with him, his
attention being devoted in particular to curare and carbon
monoxide gas.

Bernard practiced vivisection to the disgust of his
wife and his daughter. He firmly believed that the advancement of medicine and the relief
of human suffering justified the suffering of animals but his wife was not convinced, the
couple were officially separated in 1869 and his wife went on to actively campaign against
the practice of vivisection.

On his passing, Claude Bernard was interred in Le Père Lachaise Cemetery in Paris.

An Introduction to the Study of Experimental Medicine (1865)

[Note: All page references refer to the Dover edition of 1957. See
“References” below.]

In his major discourse on scientific method, An
Introduction to the Study of Experimental Medicine (1865),
Claude Bernard describes what makes a scientific theory good and what makes a scientist
important, a true discoverer. Unlike many scientific writers of his time, Bernard writes
about his own experiments and thoughts, and uses the first person.

Known and Unknown. What makes a scientist important, he states, is how well he or
she has penetrated into the unknown. In areas of science where the facts are known to
everyone, all scientists are more or less equal—we cannot know who is great. But in
the area of science that is still obscure and unknown the great are recognized: “They
are marked by ideas which light up phenomena hitherto obscure and carry science
forward” (p. 42).

Authority vs. Observation. It is through the experimental method that science is
carried forward–not through uncritically accepting the authority of academic or
scholastic sources. In the experimental method, observable reality is our only authority.
Bernard writes with scientific fervor:

“When we meet a fact which contradicts a prevailing theory, we must accept the fact
and abandon the theory, even when the theory is supported by great names and generally
accepted” (p. 164).

Induction and Deduction. Experimental science is a constant interchange between
theory and fact, induction and deduction. Induction, reasoning from the particular to the
general, and deduction, or reasoning from the general to the particular, are never truly
separate. A general theory and our theoretical deductions from it must be tested with
specific experiments designed to confirm or deny their truth; while these particular
experiments may lead us to formulate new theories.

Cause and Effect. The scientist tries to determine the relation of cause and
effect. This is true for all sciences: the goal is to connect a “natural
phenomenon” with its “immediate cause.” We formulate hypotheses
elucidating, as we see it, the relation of cause and effect for particular phenomena. We
test the hypotheses. And when an hypothesis is proved, it is a scientific theory.
“Before that we have only groping and empiricism” (p. 74).

Verification and Disproof. Bernard explains what makes a theory good or bad
scientifically:

“Theories are only verified hypotheses, verified by more or less numerous facts.
Those verified by the most facts are the best, but even then they are never final, never
to be absolutely believed.” [P. 165].

When have we verified that we have found a cause? Bernard states:

Indeed, proof that a given condition always precedes or accompanies a phenomenon does
not warrant concluding with certainty that a given condition is the immediate cause of
that phenomenon. It must still be established that when this condition is removed, the
phenomen will no longer appear…. [P. 55]

We must always try to disprove our own theories. “We can solidly settle our ideas
only by trying to destroy our own conclusions by counter-experiments” (p. 56). What
is observably true is the only authority. If through experiment, you contradict your own
conclusions—you must accept the contradiction–but only on one condition: that the
contradiction is PROVED.

Determinism and Averages. In the study of disease, “the real and effective
cause of a disease must be constant and determined, that is, unique; anything else would
be a denial of science in medicine.” In fact, a
“very frequent application of mathematics to biology [is] the use of
averages”—that is, statistics—which may give only
“apparent accuracy.” Sometimes averages do not give the kind of information
needed to save lives. For example:

A great surgeon performs operations for stone by a single method; later he makes a
statistical summary of deaths and recoveries, and he concludes from these statistics that
the mortality law for this operation is two out of five. Well, I say that this ratio means
literally nothing scientifically and gives us no certainty in performing the next
operation; for we do not know whether the next case will be among the recoveries or the
deaths. What really should be done, instead of gathering facts empirically, is to study
them more accurately, each in its special determinism….to discover in them the cause
of mortal accidents so as to master the cause and avoid the accidents. [Page 137]

Although the application of mathematics to every aspect of science is its ultimate
goal, biology is still too complex and poorly understood. Therefore,
for now the goal of medical science should be to discover all the new facts possible.
Qualitative analysis must always precede quantitative analysis.

Truth vs. Falsification. The “philosophic spirit,” writes Bernard, is
always active in its desire for truth. It stimulates a “kind of thirst for the
unknown” which ennobles and enlivens science—where, as experimenters, we need
“only to stand face to face with nature” (p. 221). The minds that are great
“are never self-satisfied, but still continue to strive” (p. 222). Among the
great minds he names Priestly
and Blaise Pascal.

Meanwhile, there are those whose “minds are bound and cramped” (p. 37). They
oppose discovering the unknown (which “is generally an unforeseen relation not
included in theory”) because they do not want to discover anything that might
disprove their own theories. Bernard calls them “despisers of their fellows” and
says “the dominant idea of these despisers of their fellows is to find others’
theories faulty and try to contradict them” (p. 38). They are deceptive, for in their
experiments they report only results that make their theories seem correct and suppress
results that support their rivals. In this way, they “falsify science and the
facts”:

They make poor observations, because they choose among the results of their experiments
only what suits their object, neglecting whatever is unrelated to it and carefully setting
aside everything which might tend toward the idea they wish to combat. [P. 38]

Discovering vs. Despising. The “despisers of their fellows” lack the
“ardent desire for knowledge” that the true scientific spirit will always
have—and so the progress of science will never be stopped by them. Bernard writes:

Ardent desire for knowledge, in fact, is the one motive attracting and supporting
investigators in their efforts; and just this knowledge, really grasped and yet always
flying before them, becomes at once their sole torment and their sole happiness….A
man of science rises ever, in seeking truth; and if he never finds it in its wholeness, he
discovers nevertheless very significant fragments; and these fragments of universal truth
are precisely what constitutes science. [P. 22]

References

• This article incorporates text from the Encyclopædia Britannica Eleventh
  Edition, a publication now in the public domain.
• Bernard, Claude. An Introduction to the Study of Experimental Medicine, 1865.
  First English translation by Henry Copley Greene, published by Macmillan & Co., Ltd.,
  1927; reprinted in 1949. The Dover Edition of 1957 is a reprint of the original
  translation with a new Forward by I. Bernard Cohen of Harvard University.

External links

Wikiquote has a collection of quotations related to: Claude Bernard

• Works
  by Claude Bernard at Project Gutenberg
• Picture, biography, and
  bibliography in the Virtual Laboratory of the Max Planck Institute for the
  History of Science

http://en.wikipedia.org/wiki/Claude_Bernard