¹ The term is absent in Souter, A Glossary of Later Latin, Oxford, 1949. It is also absent in A. Blaise, Dictionnaire latin-français des auteurs chrétiens, Strasbourg, 1954.

² Sir Thomas Heath finds an anticipation of the Newtonian law of the equality of action and reaction even in Aristotle's De Motu Animalium (c. I. 698a). Cf. Mathematics in Aristotle, Oxford, 1949, p. 281-282.

³ The formula, which is traditional, is here that of Bonamici quoted by A. Koyré, Etudes galiléennes, Paris, 1939, t. I, p. 19.

⁴ Quoted in the article "reaction" by Chambers, Trevoux, L'Encyclopédie.

⁵ G.-J. Vossius, De vitiis sermonis, IV, 20. Quoted as the only example by DuCange, Glossarium ad scriptores mediae et infimae latinitatis, article "reactio." Paris, 1734, t. V.

⁶ Littré however, indicates an older usage which has the notable advantage of revealing the presence of the term in the vocabulary of alchemy:

As fire acts in air, Thus air reacts on water, And water acts in air When fire wants to wage war.

This text is at verses 460-467 of the Complainte de Nature à l'alchimie errant. The author of this text is most probably the painter Jean Perréal (about 1460). We have been unable to find other examples of the verb réagir (to react) in France before the Physique of Champeynac (1610).

⁷ Such as it is affirmed by Thomas Aquinas, from Augustine and Aristotle, in the Summa Theologica, Ia. LXXIX, 2, 3.

⁸ The example of the water and fire is that proposed in 1644 by Sir Kenelm Digby in his Natural Bodies (XVI, 141): " If fire doth heate water, the water reacteth againe…upon the fire and cooleth it" (in OED, article react). The example is derived from the medieval tradition.

⁹ The dictionary of Féraud (1788) makes a state of a mode: reaction, to react "are used in writings on all sorts of matters." The beguiling efficacy of the lexical pair action/reaction is never felt more than in the cosmosophic specu lations of the end of the 18th century and the beginning of the 19th century. One need only name Goethe, Schelling, Edgar Poe (Eureka). Edgar Poe's specul ation will find a late echo in the Art Poétique of Claudel.

¹⁰ In 1771 the theologian Wesley evokes " a continual action of God upon the Soul and a re-action of the Soul upon God" (Works, 1872, t. V., p. 232). The example is quoted by OED, article "reaction."

¹¹ Montesquieu, Considérations sur les causes de la grandeur des Romains et de leur décadence, chap. IX.

¹² One grasps the passage from the concept "of universal reciprocal action" to that of "dialectic" in its essence in the Anti-Düring of Engels, (Introduction, chap. I): "nature is the testing ground of dialectic."

¹³ Cours de linguistique générale, Genève, 1916, second part, chap. IV.

¹⁴ For these new meanings and these derived terms, cf. F. Brunot, Histoire de la langue française, des origines à 1900, t. IX, 2, p. 837 n., and p. 843-844.

¹⁵ For Needham and his reference to the concept of " action and reaction" see Jacques Roger, Les Sciences de la vie dans la pensée française du XVIII siècle, Paris, 1963, p. 504-520.

¹⁶ Buffon, Oeuvres complètes, Paris, Duménil 1836, t. IV, p. 364-365. For the role of the image of explosion in the formation of the notion of reflex cf. Georges Canguilhem, La formation du concept de réflexe… Paris, P.U.F., 1955.

¹⁷ P.-J.-G. Cabanis, Rapports du physique et du moral de l'homme, onzième mémorie, Ch. I.

¹⁸ "Life is a series of impressions received and reactions performed by the different sensitive centers," writes Delpit in the article "reaction" of the Dictionnaire des Sciences Médicales, Paris, Panckoucke, 1820. " Just as we live ceaselessly under the influence of physical stimulations and mental affections, it follows that outside the time of sleep, we live under the rule of continual reaction," states Bricheteau in the article "reaction" of the Encyclopédie Méthodique (Médecine) t. XII, 1827. Later on, in 1874, Bernheim recognizes that " the word reaction has taken on such a large sense…that it can no longer be defined, that it no longer bears a precise meaning" (article "reaction" of the Dictionnaire Encyclopédique des Sciences Médicales, Paris, 1874, troisième série, t. II).

¹⁹ Cabanis, Rapports du physique et du moral de l'homme, deuxième mémoire, Histoire physiologique des sensations, paragraph VI. A few lines later Cabanis goes on to say "that sensibility acts like a fluid whose total quantity is determined and which, every time it casts itself in greater abundance in one of its channels, diminishes proportionately in the others." On the role of this metaphor in the history of psychiatric thought and on the image Freud makes of it cf. our study "Sur les fluides imaginaires," in La relation critique, Paris, 1970, p. 196-213.

²⁰ This will be affirmed later by empiricists like E. Mach (Die Analyse der Empfindungen, 3rd ed., Jena, 1902, p.245-246). In the Cahiers (2 vol., Paris, 1973) of Paul Valéry, we find the peremptory affirmation: "The notions of thought, knowledge, etc. must be discarded. Those of act and reaction must replace them." (I, 954). The psychology of Jean Piaget, which insists on action, assimi lation and accommodation seems aimed entirely at resuming and surpassing, in a decidedly active sense, all that the long dominant concept of reaction led to believe about the necessary link between the individual and the surrounding world: knowledge is a constructed response.

²¹ J. Capuron, Nouveau dictionnaire de médecine, de chirurgie, de physique…, Paris, 1806. Capuron's definition is repeated unchanged by M.-L. Hanin, Vocabu laire médical, Paris, 1811, and again in the first edition of the Dictionnaire de médecine of P.-H. Nysten. For the spiritualism of Capuron (an old Oratorian) and the vitalism of Nysten (disciple of Bicchat), cf. Marcel Florkin, Médecine et médecins au pays de Liège, Liège, 1954, p. 169-190.

²² Réflexions physiologiques sur la vie et la mort, 1880, première partie, article 1.

²³ For another physiologist fifty years later the concept of reaction intervenes once again in a fundamental definition. But for Moritz Schiff, it is not longer a question of defining life in general: it is a question of the speciality of animal life. And reaction is no longer conceived as a response to an external environment; it establishes the solidarity of the parts. "There exists…in the animal a reciprocal reaction of all the parts in which one can respond to the irritation of the other. This reciprocal unity gives the animal a kind of individuality that is lacking in plants." Moritz Schiff, Recueils des mémoires physiologiques, Lausanne, 1894, I, p. 464.

²⁴ Dictionnaire des sciences médicales, t. 47, Paris, Panckoucke, 1820. Article "réaction." J.F. Delpit. This doctor, doctor at the University of Montpellier, was the friend of Maine De Biran with whom he founded the Medical Society of Bergerac in 1806. Cf. Maine de Biran, Journal, complete edition published by Henri Gouhier, 3 vol., Neuchâtel, 1954.

²⁵ Encyclopédie Méthodique, Médecine, t. XII, Paris, Agasse, 1827, article "reaction." Isidore Bricheteau (1789-1861) was doctor at the Necker hospital and member of the Academy of Medicine.

²⁶ Among historians the term has led to confusion. There is a great difference to be established between cosmic sympathies, postulated by the paracelsian doctors of the 16th and 17th centuries and physiological sympathies for which the theory was developed in the 18th century by the school of Montpellier and especially by Barthez. It will be demonstrated that the system of sympathy developed concurrently with the system of reaction and that both were supplanted at the same time by the recognition of reflex movements.

²⁷ Dictionnaire des sciences médicales, t. 47, Paris, 1820, article "réaction."

²⁸ Encyclopédie Méthodique. Médecine, t. XII, Paris, Agasse, 1827, article " réaction."

²⁹ Cf. Aubrey Lewis, "'Psychogenic': a Word and Its Mutations." Psychological Medicine, vol. 2, n. 3, August 1972, p. 209-215.

³⁰ H. de Balzac, Adieu, in La Comédie Humaine, Paris, Ed. du Seuil, l'Inté grale, t. VII, p. 58. The principal text of Balzac is Louis Lambert: the theory of will as it is developed by the hero of this novel is a doctrine of action and reaction. We have devoted more thorough attention to this in "La vie et les aventures du mot ‘reaction'," Modern Language Review, October 1975, vol. 70, n. 4.

³¹ Delpit, loc. cit.

³² Cf. in particular the treatises Du Médecin and De la Bienséance. These two treaties are found in the t. IX of the Littré edition.

³³ Dictionnaire des sciences médicales, t. 47, Paris, 1820, article "réaction."

³⁴ Article "réaction" of the Dictionnaire encyclopédique des sciences médicales, troisiéme série, t. 2, Paris, 1874.

³⁵ On his role in the scope of modern psychiatry, cf. Henry F. Ellenberger, The Discovery of the Unconscious, New York, 1970, p. 85-89 et passim.

³⁶ For Claude Bernard "the most superficial examination of all that happens around us shows us that all natural phenomena come from the reactions of bodies upon each other" (Introduction à l'Etude de la Médecine expérimentale, II, I, VII). Research will only become exact when it will apply itself to intercepting the determinism that governs " the reciprocal and simultaneous reactions of the internal environment on the organs and of the organs on the internal environment " (II, II, 3).

36 Studien über Hysterie, Vienne, 1895.

³⁷ Karl Jaspers. Allgemeine Psychopathologie, 5th edition, Berlin and Heidel berg, 1948. Second part, chap. ii, sect. II, I, p. 319-327.

³⁸ Cf. Aubrey Lewis, "'Endogenous' and ‘Exogenous': a useful dichotomy?," Psychological Medicine, vol. I, n. 3, May 1971, p. 191-196.

³⁹ The principal articles of Adolf Meyer have been collected in Alfred Lief, The Commonsense Psychiatry of Dr. Adolf Meyer, New York, Toronto, London, 1948. See in particular pages 193-206.

⁴⁰ On the precautions to take in the evaluation of the influence of determinant factors cf. Brian Cooper and Michael Shepherd, "Life change, stress and mental disorder: the ecological approach," in Modern Trends in Psychological Medicine, 2, Ed. J.-H. Price, 1970, p. 102-130.

⁴¹ This study is the completed and considerably revised version of what appeared on the same subject in Confrontations psychiatriques, n. 12, 1974.