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“The Newton of the Grass-Blade”

Alain PROCHIANTZ
p. 60-62

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Pre-war bronze statue of Claude Bernard, requisitioned by the Germans in 1941 and replaced in 1946 by the current stone replica, ARR

1Claude Bernard was born in 1813, and we are celebrating his 200th birthday. The celebration seems timid compared to the value of the work
of the inventor of physiology.

  • 1 Claude Bernard, An Introduction to the Study of Experimental Medicine, Macmillan & Co, 1927 [1865].
  • 2 Georges Canguilhem, Knowledge of Life, Fordham University Press, 2008 [2003].

2It is true that Bernard had the bearing of a man of dis­tinction and that, if my memory serves me right, his Introduction to the Study of Experimental Medicin1, as it was fed to several generations of high school pupils, probably did not help to make him appealing. Fortunately, reading Georges Canguilhem2, among other philosophers, reconciled us with this work and, more generally, with all of the physiologist’s writings.

  • 3 Claude Bernard, Lectures on the Phenomena of Life Common to Animals and Plants, Thomas, 1974 [1878- (...)

3Pierre Corvol adequately set the scene in the pages above for us to claim outright that Bernard entered physiology through the mouth. That is, through nutrition. The washed-liver experiment (was it really a dog or a rabbit?) and the two discordant measurements of the liver sugar content set him on the trail of the liver glycogenic function, and thus of the capacity of animals to accumulate sugar reserves in the form of glycogen and to release them in the form of glucose (glycose at the time). Animal glycogen is like plant starch and Bernard was later to draw the physiological parallel between the two kingdoms of nature, in his lectures at the Muséum d’histoire naturelle, which he delivered in 1878, the year of his death3.

4This is obviously very important, though surely not as much as the concept of milieu intérieur born from this experiment, which was also the transposition in the life sciences of the concept of milieu in physics, or rather of the post-Newtonian physicists’ notion of ether. The concept of force – also transposed from Newtonian physics –, along with that of regu­lation, comes with it, as the organisms’ milieu intérieur has to remain constant or more or less so, and in any case has to adapt dynamically, in order to ensure survival.

  • 4 Alain Prochiantz, Claude Bernard. La révolution physiologique, Paris, Presses universitaires de Fra (...)

5Without seeking to revive timeworn ideas4 it seems import­ant to me to consider this work along two main lines. The first is that of method, with which we are most familiar since it brings back to mind our final year of high school. What is at stake, however, is not a Discourse on Method, a sort of “how to reason?” or “how to find?”, that could have a universal value. Bernard is not the Descartes of the nineteenth century. Rather, his approach is pragmatic, in that it defends the right to delve into the milieu intérieur of live animals, through the use of vivisection and of poisons, beyond philosophical considerations. It refers to a very concrete endeavour, as is now the concrete manipulation of genomes, the pathway to the modification of the milieu intérieur.

  • 5 Claude Bernard, Principes de médecine expérimentale, Paris, Presses universitaires de France, 1987 (...)

6Nutrition is the second theme of reflection on the physi­ologist’s contribution. The passage through reserves, then the release of the basic nutrients (sugars, amino acids, fatty acids, etc.) through the bloodstream and through the interstitial milieu so as to reach each cell of the organism clearly departs from a Lavoisierian conception, where nu­trition is reduced to an energy balance sheet between what the organism absorbs and what comes out of it. Nutrition is no longer simply an organic combustion. It also becomes an organogenic or morphogenetic process given that the organs and the organisms retain their forms, that is, also their physio­logical functions, despite the renewal of nutrients. Although nineteenth-century physiologists could not explain the origin and the evolution of forms, nor their development or their maintenance in adults, Claude Bernard believed that this would be possible in the future5:

“I am perfectly willing to accept the fact that when physiology will have sufficiently advanced, physiologists will be able to make new animals and plants, just like the chemist produces bodies which have the potential to exist, but that do not exist in the natural state of things… But physiology will have to act scientifically… for it will know the intimate laws of the formation of organic bodies, just as the chemist knows the laws of the formation of mineral bodies. Experimental biological science therefore acts with knowledge of the law of formation of organized bodies…”

7This citation (which I have often used – may my colleagues and readers forgive me for this), brings us to the mainten­ance of forms in adults, their “silent embryogenesis”, to use the Bernardian expression. Underpinning the idea of organogenic nutrition is the on-going renewal of structures. This is what the bringing together of the two aphorisms “life is creation” and “life is death” means. Far from contradicting each other, they are complementary, the two movements of death and creation compensating for each other, as Bernard contended in the Lectures on the Phenomena of Life Common to Animals and Plants.

  • 6 Xavier Bichat, Physiological Researches upon Life and Death, Philadelphia, Smith & Maxwell, 1809 [1 (...)
  • 7 Léon Brillouin, Vie, matière et observation, Paris, Albin Michel, 1959.
  • 8 François Jacob, La logique du vivant, Gallimard, 1970.

8This marks a clear break away from Bichat for whom “life is the assemblage of the functions which resist death”6. Furthermore, it veers away from a thermodynamicist vision of life and death, whereby life is order and death is an increase of the disorder that precedes the tilting over into organic nothin­gness. Hence, after having broken with Lavoisier and the first principle of thermodynamics, Bernard, with his conception of nutrition, also distanced himself from Carnot, the father of the second principle. This point seems important to me, given that, to a large extent, contemporary biology made a detour through information theory and cybernetics, which we know are closely linked to the second principle of thermodynamics7.This was particularly the case for bacterial genetics, to which we owe many of the concepts that are still used in our biological disciplines8.

  • 9 Erwin Schrodinger, What is life? Cambridge University Press, 2012 [1944].

9Bernard’s work is therefore isolated from the thermodynamicist conception of living forms that precedes it, but also from the one that followed it and that was well illustrated by the scientific and ideological role that Erwin Schrödinger’s “what is life?” came to play9. This can partly explain that a scholar, who played an equally important role in nineteenth-century physiology as Darwin did for evolutionism, underwent a relative purgatory. In both cases, however, and as Canguilhem pointed out, there is a question of milieu and adaptation, as well as evolution, given that physiological adaptation relies on a renewal of living forms which is not necessarily their exact reproduction, even if their function must be preserved.

  • 10 Alain Prochiantz, Qu’est-ce que le vivant ? Éditions du Seuil, 2012.

10 In conclusion, I would like to suggest that physiology is on the way to becoming Bernardian again. This is so first in view of our ability to “make new animals and plants” by acting directly on genomes, in line with Bernard’s visionary pre­diction. But it is also (or perhaps especially?) the case given our con­temporary understanding of living forms. I recently talked about this and I am here doing so again only to highlight the fact that life is unstable at all levels10. Although at the level of species, or of individuals, instability is obvious because it is visible; instability and the renewal associated with it (“life is creation” and “life is death”) is the rule at all structural levels: genomes, membranes, cells, etc. Physiology is embedded in this permanent renewal of forms, which is the basis of re­generative medicine. Likewise, in it we find the etiology of pathologies, which may now be discovered in what derails during a morphogenetic process that ceases only with death. Here is yet another Bernardian reference, as Bernard was the first to teach us that there is not one physiology for the normal and another for the pathological.

11“Physiological, pathological and therapeutic phenomena are all explained by the same evolutionary laws and differ only in particular conditions, through particular determinism”.

12- Claude Bernard?

13- Claude Bernard of course (Principes de médecine expé- rimentale).

14Claude Bernard, Pioneer of Experimental Medicine

While the term “experimental medicine” may seem paradoxical at first, as patients cannot a priori be considered as experimental objects, Bernard’s fundamental scientific contribution was to envisage medicine as a research subject in a radically new way. This fundamental theoretical advance, which from then on gave doctors the dual function of practitioner and researcher, can be characterized by three key dates attached to Bernard’s name:

• 1865: Bernard published Introduction to the Study of Experimental Medicine.

• 1958: the Debré reform of University Hospitals was the first to introduce clearly the notion of “doctor researcher”.

• 1988: the Huriet-Sérusclat law set a legal framework for clinical trials and experiments on patients.

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Notes

1 Claude Bernard, An Introduction to the Study of Experimental Medicine, Macmillan & Co, 1927 [1865].

2 Georges Canguilhem, Knowledge of Life, Fordham University Press, 2008 [2003].

3 Claude Bernard, Lectures on the Phenomena of Life Common to Animals and Plants, Thomas, 1974 [1878-1879].

4 Alain Prochiantz, Claude Bernard. La révolution physiologique, Paris, Presses universitaires de France, 1990.

5 Claude Bernard, Principes de médecine expérimentale, Paris, Presses universitaires de France, 1987 [1947].

6 Xavier Bichat, Physiological Researches upon Life and Death, Philadelphia, Smith & Maxwell, 1809 [1799].

7 Léon Brillouin, Vie, matière et observation, Paris, Albin Michel, 1959.

8 François Jacob, La logique du vivant, Gallimard, 1970.

9 Erwin Schrodinger, What is life? Cambridge University Press, 2012 [1944].

10 Alain Prochiantz, Qu’est-ce que le vivant ? Éditions du Seuil, 2012.

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Table des illustrations

Légende Pre-war bronze statue of Claude Bernard, requisitioned by the Germans in 1941 and replaced in 1946 by the current stone replica, ARR
URL http://lettre-cdf.revues.org/docannexe/image/2041/img-1.png
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Alain PROCHIANTZ, « “The Newton of the Grass-Blade” », La lettre du Collège de France [En ligne], 8 | mars 2014, mis en ligne le 12 août 2015, consulté le 22 juillet 2017. URL : http://lettre-cdf.revues.org/2041

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Alain PROCHIANTZ

Morphogenetic Processes

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