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Helmont, Johannes (Joan) Baptista Van

Helmont, Johannes (Joan) Baptista Van

(b. Brussels, Belgium, 12 January 1579; d. Brussels, 30 December 1644)

chemistry, natural philosophy, medicine, mysticism.

Helmont was from the Flemish landed gentry. His father, Christian van Helmont, was state counselor of Brabant; his mother was Marie de Stassart, of Brussels. In 1609 he married Margerite van Ranst, of the Merode family, and through her became manorial lord of Merode, Royenborch, Oorschot, and Pellines. They had several daughters and one son, Franciscus Mercurius, who edited his father’s collected works—the Onus medicinae of 1648-and became known through his collaboration on the Kabbala denudata (edited by Knorr von Rosenroth, 1677–1684), his early attempts at teaching the deaf and dumb (1667) and orthopedic treatment of spinal deformity, his friendship with Lady Conway and Leibniz, his life as a wandering courtier and scholar, and his theosophical treatises.

Helmont’s formative years were marked by growing skepticism, dissatisfaction with the traditional syllabus, and the combination of mysticism with genuine scientific research. His unorthodox career was due partly to his Flemish family background, combined with his natural enmity to the Schoolmen and Jesuits brought to Belgium following the Spanish occupation. His first course in classics and philosophy was followed from 1594 by studies in a variety of subjects from geography to law, “reaping straw and poor senseless prattle,” especially in Martin del Rio’s discourses against natural magic and in the study of Stoicism and medical textbooks.

After receiving the M.D. in 1599 Helmont realized the need for more than book learning in medicine. He sought this knowledge on visits to Switzerland and Italy in 1600–1602 and to France and England in 1602–1605; there may have been two London visits. one dated by himself as in 1604 and the other when he “Conversed with the Queen herself,” probably at the close of 1602. In spite of some medical success—for instance, during an epidemic of plague at Antwerp in 1605—and tempting offers from Ernest of Bavaria, the archbishop of Cologne, and Emperor Rudolf II, which he declined, refusing to “live on the misery of my fellow men” or to “accumulate riches and endanger my soul,” he embarked on private research for seven years (1609–1616) at Vilvorde, near Brussels. On his journeys Helmont had learned as little as before and felt the need to explore the first principles of nature in order to rise above the “dung” of traditional learning. He hoped to overcome the prevalence of “useless logic” and entia rationis therein by “dismantling” the operations of nature and art and by promoting the seminal virtues of all things through chemistry (pyroechnia, perignem). In this and in the interest which he took in the controversy over the “weapon salve” and the magnetic cure of wounds, he was influenced by Paracelsus. This involved him in ecclesiastic prosecution for most of the rest of his life.

In 1608 Rudolf Goclenius, Protestant professor of philosophy and a believer in natural magic, published his first treatise affirming the efficacy of a pseudo-Paracelsian ointment applied not to the wound but to the weapon and acting by sympathy over long distances. Between 1615 and 1625 seven attacks and counterattacks were exchanged between Goclenius and the Jesuit Johannes Roberti, who condemned the method as “devil’s deceit.” In 1621 Helmont’s treatise De magnetica vulnerum... curatione was published at Paris, possibly at Roberti’s instigation and against Helmont’s will. His argument was naturalistic: Goclenius had been wrong in omitting the presence of inspissated blood on the weapon as essential for the sympathetic effect; on the other hand, Roberti had recourse to the field most unsuitable for assessing natural phenomena—theology and activity of the devil. Helmont considered the effect to be as genuine as those of sympathy and antipathy reported in many tall stories that he related, interlarding his account with satirical invectives against the Jesuits. In 1623 Helmont’s “monstrous pamphlet” was denounced by members of the Louvain Faculty of Medicine, probably at the instigation of his literary enemy Henry van Heers.

In 1625 the General Inquisition of Spain condemned twenty-seven of Helmont’s “propositions” for heresy, impudent arrogance, and association with Lutheran and Calvinist doctrine. The treatise was impounded the following year, and in 1627 Helmont asserted his innocence and submission to the church before the curia of Malines, which referred the matter to the Theological Faculty of Louvain. He again acknowledged his error and revoked his “scandalous pronouncements” in 1630. Helmont was condemned by the Louvain Theological Faculty in 1633–1634 for adhering to the “monstrous superstitions” of the school of Paracelsus (that is, the devil himself), for “perverting nature by ascribing to it all magic and diabolic art, and for having spread more than Cimmerian darkness all over the world by his chemical philosophy (pyrotechnice philosophando).”

Helmont was placed in ecclesiastical custody for four days in March 1634, then was transferred under high security to the Minorite convent at Brussels. After several interrogations he was released but placed under house arrest. This was finally lifted in 1636, but church proceedings against him were not formally ended until 1642, two years before his death. Also in 1642 Helmont obtained the ecclesiastic imprimatur for his treatise on fever, and in 1646 his widow received his official religious rehabilitation from the archbishop of Malines. The “monstrous pamphlet,” De magnetica vulnerum... curatione, was reprinted in the Ortus medicinae, not necessarily by Helmont’s wish; it may have been inserted by his son, who was editor of the Onus.

Helmont’s scientific method and achievement resulted from his extensive use of the balance, quantification, and experiment. Aiming at the invisible, the semina, and forces in visible objects, Helmont applied chemical analysis to the smoke that remains after combustion of solids and fluids. He found this smoke to be different from air and water vapor in that it displays properties specific to the substance of origin. He called the “specific smoke” by the “new term gas” (from chaos or perhaps gaesen, that is, to effervesce or to ferment). It was also termed “wild” (spiritus sylvestris), since it could not be “constrained by vessels nor reduced into a vistble body” Helmont described and identified a number of such gases, notably carbon dioxide and, in some cases, carbon monoxide, from burning charcoal, fermenting wine, mineral water, eructations, and the reaction of sulfuric acid and salt of tartar or of distilled vinegar and calcium carbonate. Others were chlorine gas from the reaction of nitric acid and sal ammoniac; a “gas pingue” from dung, the large intestine, or dry distillation of organic matter; sulfur dioxide from burning sulfur (a fatty and combustible phlogiston); the explosive gas from an ignited gunpowder mixture of charcoal, sulfur, and saltpeter; and a “vital” gas in the heart and the blood. Helmont is therefore remembered today as the discoverer of gas.

On the indestructibility of matter, Helmont stated that metals dissolved in acid are not thereby destroyed or transmuted but are recoverable in their original quantity; for instance, silver dissolved in nitric acid is comparable to a watery salt solution. One metal can precipitate another metal—for example, iron can precipitate copper from a vitriol solution—a process which before Helmont had been attributed to transmutation.

Helmont also designed advanced methods for the preparation of sulfuric acid, aquafortis (nitric acid), and in particular hydrochloric acid (spiritus salis marini from sea-salt and potter’s clay). He studied a variety of alkali salts and was familiar with the neutralizing effect of alkali on acid (notably, following acid digestion, in the duodenum).

Chemical medicines prescribed by Paracelsus, notably mercury preparations, were improved and widely used by Helmont. He also discussed the sedative and narcotic effects of the Paracelsian “sweet spirit of vitriol” (ether). Helmont recognized specific gravity as an important diagnostic indicator and an aid in chemical research. He determined it for metals and notably for urine, thus replacing Leonhard Thurneisser’s chemical uroscopy, Helmont devised an air thermometer-barometer, and he also used and recommended the pendulum for measuring time and for assessing the destructive powers of vacua and projectiles. In this effort he determined that the resistance of the air, the quality of the powder, the size of the bullet, and the distance of the target were significant for variations in the “swiftness, powers and proportions of motions.” He realized the significance of the length—as opposed to the weight—of the pendulum and that the duration of its swings is constant.

Helmont demonstrated acid as the digestive agent in the stomach (following up hints given by Paracelsus—his acetum esurinum [“hungry acid”]—and by Quercetanus [Joseph Du Chesne] in 1603, and the elusive Fabius Violet [Sieur de Coquerey, possibly a pseudonym for Du Chesne] in 1635). Helmont himself came close to identifying digestive acid with hydrochloric acid. He also recognized tissue acidity as the cause of pus formation. He described the rhythmic movement of the pylorus and its directing action on digestion; the important role of bile (hitherto regarded as “excremental” and noxious) in the alkaline digestive milieu of the gut; and the combination of blood with a “ferment from the air” (magnale), whereby venous blood disposes of a residue that escapes through the lungs in the form of “volatile salts.”

Helmont is foremost among the founders of the modern ontological concept of disease. Following Paracelsus, he denied the traditional view of the ancients who believed that diseases were due to an upset of hmmoral balance (dvsamia) and varied according to individual mixture of humors and qualities (temperament); there were no diseases as discrete entities, but only diseased individuals.

By contrast, Helmont regarded each disease as a morbid ens, with a specific morbid semen. The latter he believed to be “fertilized” and activated by a “program of action,” the morbid image or idea that it contained. This image or idea was “conceived” by the vital principle (archeus) of a single organ or the organism as a whole when it was irritated or perturbed by a pathogenic agent, usually from outside. Helmont visualized this agent as endowed with an archeus of its own, like any other object in nature, and hence able to penetrate another object, including the human archeus. Interaction between these archei produces the morbid ens. Although begotten by the archeus of the patient, the ens is not identical with that archeus, nor with the pathogenic irritant. The latter, however, “seals” the morbid ens. The specific disease then is the result of the conversion of the morbid idea into corporeal effects and local changes.

Through this ontological concept of each disease as a specific entity came the understanding that a variety of diseases are determined by specific pathogenic agents and by primarily local changes. Agents plus changes—the products of a complicated psychophysical interplay of vital principles—act parasitically and weaken the archeus so that it is no longer able to act for the common weal. Helmont’s rejection of the traditional explanation of all diseases in terms of the “madness of catarrh,” that is, down-flow of corrosive mucus produced by vaporized ingesta ascending and condensing in the “cold” brain, was a most conspicuous advance. He demonstrated the local nature of mucus formation and anatomical changes.

His reflections bore fruit in a number of ingenious and advanced observations, especially those concerning the various forms of asthma (the “epilepsy of the lungs”). He identified the causes of hypersensitivity in asthma, notably dust inhaled while working, food, hereditary susceptibility, climate and weather, and, above all, suppressed emotion: “A citizen being by a Peer openly disgraced and injured; unto whom he might not answer a word without the fear of his utmost mine; in silence dissembles and bears the reproach: but straightway after, an Asthma arises” (Onus [1648], p. 367). Tissue irritability, tonic and clonic muscle movement, and their independence of the brain were also carefully observed by Helmont, especially in hysteria and epilepsy, as was the association of hydrops and edema with the kidney. The changes caused by tuberculosis (cavities) were clearly recognized as the result of a local metabolic change in the air passages of the lung obstructed by inspissating (“caseous”) and, finally, calcifying local secretion. Fever he declared not to be the product of humoral putrefaction, as the ancients believed, but a movement in reaction to irritation and, thus, a natural healing process, Consequently. Helmont rejected traditional therapy (directed against humoral imbalance as a whole), notably bloodletting and purging, and replaced it with remedies specifically considering the type of disease, the organ affected, and the causative agent, since no change in blood or humors, in heat or cold, in moisture or dryness will ever achieve the removal of the “thorn.”

Helmont’s discoveries and advanced scientific and medical views are embedded in his discourses on natural philosophy, cosmology, and religious metaphysics, which are not scientific and are difficult for the modern reader to comprehend—hence the ambivalence in the assessment of Helmont by historians. He is either praised as an exponent of the scientific revolution of his century or condemned as a Hermetic and an occultist. The former view is reached by selection from his works of what seems relevant today or served as a stepping-stone toward modern results and by omission of what does not. The latter view is based on a refusal even to examine his scientific and medical work, since no merit can be expected from a mind that was capable of belief in the philosophers’ stone, the magnetic cure of wounds, spontaneous generation, and many other “Hermetic” tenets now recognized as unreal. Obviously neither of these views has a place in history. One must perform a synoptic analysis of the two components of Helmont’s work—the scientific and the nonscientific—of how they promoted each other, and of what significance must be attached to their coexistence in terms of the original meaning of concepts that have entered science in one form or another.

A revealing example is the discovery for which Helmont is still remembered in the annals of chemistry, that of gas. For Helmont, gas was bound up with his ideas on matter, its relationship to spirit and soul, and indeed his religious cosmology as a whole. When an object was converted into gas by chemical manipulation, it had lost its shape but had lost nothing essential. On the contrary, it had retained, and now displayed, its pure essence. This essence, the gas or archeus of the object, was not in the object but was the object itself in a volatile—spiritualized—form. Hence gas was matter and spirit at the same time—but not simple, inert matter, which Helmont believed to be water. It was matter specifically disposed or “sealed,” matter active and alive by virtue of form and function specific to it. It was spirit—but not one that was added, entering and directing matter from outside. In other words, gas represented what was specifically characteristic of each individual object; it was the material manifestation of individual specificity. Hence there were as many gases as there were individual objects. In this view, spirit and matter were regarded as two aspects of the same thing; this was a monistic and pluralistic view of a world consisting of monads (semina) and thus was opposed to a dualistic separation of matter and soul. Helmont believed that he had found in gas the empirical solution to the perennial problem of spirit and matter, soul and body. Seen in this light, gas was conceptually related to Aristotle’s entelecheia, but Helmont emphasized that the latter was an ens rationis, a product of human reason, whereas gas was divine truth and reality that could be visualized in the test tube.

Opposing the traditional (“heathen”) doctrine of the elements and regarding matter as water, Helmont seems to have been influenced by the biblical and Gnostic-alchemical tradition as well as by Nicholas Cusa. The latter—probably following an early Gnostic (pseudo-Clementine) source—had indicated that plants consist largely of water: the earth in which they grow fails to lose any weight in the process. This was demonstrated in Helmont’s experiment in which a willow tree weighing five pounds was planted in 200 pounds of earth. Five years later, the weight of the tree had increased to 169 pounds while the earth had lost no weight. The influence of Cusa on Helmont’s use of the balance and quantification is also shown in his examination of specific weights, a method recommended specifically by Cusa to replace the pseudo knowledge of the scholar (orator, philosophus) with the simple wisdom of the empiric (idiota, meanicus). Helmont’s general tendency to divest objects of their material cover, to “spiritualize” them, and to study the volatile nucleus reveals the influence of Neoplatonism; it is also recognizable in the vitalistic and idealistic interpretation of biological as well as chemical processes, notably of fermentation and the ens morbid as image or idea.

Helmont was also a follower of Paracelsus and can be regarded as the outstanding and most successful of the second generation of Paracelsists. He implemented and advanced Paracelsian philosophy and cosmology through a series of new observations and techniques—which did not hinder him from criticizing and deviating from it on several points. For example, he rejected the interpretation of natural phenomena in terms of astrology and analogy between macrocosm and microcosm—both fundamental to Paracelsus. Moreover, Paracelsus had been familiar with acid digestion in the stomach of some animals and its improvement through the intake of acid with certain mineral waters. Helmont demonstrated that acid is the digestive factor in all animals, and he came close to identifying it with hydrochloric acid. Paracelsus used the term “chaos” (probably the etymological root of “gas”) for a variety of ambient media, notably air, from which living beings derive their nourishment. He also spoke of an “essential spirit” in each individual object and of chemical manipulation whereby an inert substance could be made active (männisch), notably a salt that became a “violent spirit” on resolution. This may have influenced Helmont to call “certain exhalations that had been quiet before and become wild on dissolution in nitric acid or vinegar” spiritussylvestres. This terminology is found in Helmont’s early treatise on the waters of Spa (1624), in which he says that he calls these exhalations “wild” because they resist attempts at solidification, escaping from or breaking the glass if it is sealed before they develop. In subsequent treatises this behavior is said to be characteristic of gas, notably of carbon dioxide. Some remote influence of Paracelsus in this is therefore not unlikely. Yet it cannot be said that the latter had conceived of anything as consistent and scientific as Helmont’s discovery. He had at best vague premonitions of it when he emphasized the volatility and specificity of the arcana, the invisible bearers of active impulses in nature.

Like Paracelsus, Helmont was not really an alchemist, although at one time he claimed to have received a specimen of the “stone” and to have accomplished transmutation. In fact he normally practiced genuine chemistry. Contrary to Paracelsus, he opposed the opinion that precipitation of one metal from a solution by addition of another metal was due to transmutation, and he gave the proper explanation of the process in scientific terms. He also dropped most of the alchemical symbolism and retained little that was “Hermetic.” Nevertheless, Helmont was no scientist pure and simple. The blending of his interests and motives—scientific and nonscientific—is well shown in his ideas on biological time. Against Aristotle, he argued that time is not definable in terms of motion and succession; it is indivisible and devoid of succession, being essentially bound up with duration. This is shown in the life-span and life rhythm specific to each individual and given to the divine semina by the Creator. By virtue of this participation in divinity, time (duratio) was not different from eternity, as propounded in the Christian (Augustinitian) doctrine. On the other hand Helmont showed himself influenced by St. Augustine in visualizing divine semina (monads) as the essential components of the universe. His skepticism toward complacent human reasoning and the application of “useless logic” to natural philosophy has also a root in Christian religion and mysticism which is equally recognizable in his fondness for dreams and visions. In these he hoped to achieve union with the object and thus with divine truth. Setting out on the search for the divine sparks in nature, Helmont found his way paved with scientific problems that provided the inescapable challenge directing him to scientific discovery.


I. Original Works. Published in Helmont’s lifetime were De magnetica vulnerum naturali et legitima curatione contra R. P. Joannem Roberti (Paris. 1621): for bibliographical notes see A. J. J. Vandevelde (below), pt. 2, p. 720; Supplementum de spadanis fontibus (Liege, 1624); see Vandevelde, pt. 2. pp. “22 “23. including a bibliography of Henry van Heers, who believed that he was being criticized through Helmont’s treatise; Febrium doctrind inaudita (Antwerp, 1642); see Vandevelde, pt. 2, p. 724; and Opuscula medica inaudita: I. De lithiasi; II. De febribus (2nd ed. of Febrium doetrina inaudita III. Scholarum humoristarum passiva deceptio atque ignorantia; IIIa. Appendix ad tractatum de febribus sine caput XVI et XVII (not extant in 1st ed. of Febrium doctrina inaudita); IV. Tumulus pestis (Cologne. 1644); see Vandevelde, pt. 2; pp. 725 –29.

Posthumously published was Ortus medicinae. Id est initia physicae inaudita. Progressus medicinae novus, in morborum ultionem, ad vitam longam... edente... Francisco Mercurio van Heimont cum ejus praefatione (Amsterdam. 1648), followed by the Opuscula (repr. from the 1644 ed.), the first collected ed. of Helmont’s works. Further eds. were issued at Venice (1651), the first to have an index; Amsterdam (1652), termed the “best” ed.; Lyons (1655, 1667); Frankfurt (1682); and Copenhagen (1707).

Translations of the Ortus are 1. Chandler. Oriatrike or Physick Refined (London. 1662. 1664); Jean le Conte, Les oeuvres de Jean Baptist Van Helmont (Lyons, 1671), selected chapters only and unsatisfactory; and Christian Knorr von Rosenroth, Aufgang der Arztney-Kunst (Sulzbach, 1683; repr, in 2 vols., Munich, 1971). extremely useful, since it contains commentaries and incorporates translated supplementary passages from the Dageraed (see below).

Translations of separate treatises from the. Onus are Walter Charleton, Ternary of Paradoxes of the Magnetick Cure of Wounds. Nativity of Tartar in Wine. Image of God in Man (London, 1650); and Deliramenta catarrhi or The Incongruities, Impossibilities and Absurdities Couched Under the Vulgar Opinion of Defluxions (London, 1650); J. H. Seyfried, Tumulus pestis. Das ist Grüundlicher Ursprung der Pest (Sulzbach, 1681), largely following the text of the Dageraed (not mentioned in the bibliography, but a copy is in the Munich State Library and the author’s possession); Die Morgenröthe (n.p., n.d. [mid-nineteenth century]), repr. of five treatises from Knorr von Rosenroth’s Aufgang; Walter Pagel, “Irrwitz der Katarrhlehre. Asthma und Husten. Tobende Pleura,” in his jo. Bapt. van Helmont (see below), pp. 144–219; and trans. of Helmont’s On Time, chaps. 1–46, in Osiris (see below), pp. 356 376.

Considered separately is Dageraed oft nieuwe opkomst der geneeskonst in verborgen grondt-regelen der natuere (Amsterdam, 1659; Rotterdam, 1660); see Vandevelde, pt. l, 457; also in facs. repr. (Antwerp, 1944).

It should be noted that the Dageraed gives treatises in Flemish but is not a Flemish version of the Ortus, On the contrary, it seems to have been written earlier and compiled by Helmont himself, while the Onus was posthumously arranged, edited, and prefaced by Helmont’s son. It is more concise than the Onus, and Helmont gives as his motive for writing in the vernacular that truth never emerges more “naked” than when offered in a simple style that makes it accessible and profitable to the common man. Why its publication should have been delayed for some fifteen years after his death is not clear (the 1615 ed., first erroneously referred to in 1826, is a ghost. Nobody has ever seen it and in it events are mentioned after 1615).

The research on which both the Onus and the Dageraed are based goes back largely to 1609–1616. When Helmont’s house was searched in 1634, no relevant MSS were found; and between 1624 and 1642 nothing was published. Thus most of the works were likely written in 1634–1640. notably during his house arrest in 1634–1636. Finally, Helmont’s correspondence with Père Mersenne should be mentioned as published in Mme. Paul Tannery and Cornelis de Waard, Correspondence du P. Marin Mersenne. Réligieux Minime, vols. 1–111 (Paris, 1932–1946), with three letters in vol. II and eleven in vol. III from the years 1630–1631.

II Secondary Literature. Biographical and bibliographical material is found in C. Broeckx, Commentaire de J. B. van Helmont sur le premier livre du Régime d’Hippocrate: Peri diaites (Antwerp, 1849), one of Helmont’s juvenilia, published from the MS for the first time; other juvenilia not extant elsewhere: “Commentaire de J. B. van Helmont sur un livre d’Hippocrate intitulé: peri trophes,” in üAnnates de l’Acadéemic archéol. belg., 8 (1851), 399–433, reprinted separately (Antwerp, 1851); “Le premier ouvrage (Eisagoge in artem medicam a Paracelso restitutam 1607) de J.-B. van Helmont,” ibid., 10 (1853). 327–392, and 11 (1854), 119–191, reprinted separately (Antwerp, 1854); “Notice sur le manuscrit Causa J. B. Helmontii. déposé aux archives archiépiscopales de Malines.” ibid., 9 (1852). 277–327, 341–367. reprinted separately (Antwerp, 1852); “Interrogatoires du docteur J. B. van Helmont sur le magnétisme animal,” ibid., 13 (1856), 306–350, reprinted separately (Antwerp, 1856); and Apologie du magnétisme animal (Antwerp. 1869); G. des Marez, “L’état civil de J. B. van Helmont,” in Annales de la Société ds’archéologie de Bruxelles, 21 (1907). 107–123; Néve de Mévergnies, Jean-Baptiste van Helmont. philo-sophe par le feu (Paris, 1935), useful in its biographical section; A. J. J. Vandevelde. “Helmontiana,” 5 pts., in Verslagen en Mededeelingen. K. Vlaamsche Academie voor Taalen Letterkunde, pt, 1 (1929), 453–476: pt. 2 (1929), 715–737; pt. 3 (1929). 857–879; pt. 4 (1932), 109–122: pt, 5 (1936), 339–387: H. de Waele, J. B. van Helmont (Brussels. 1947). reviewed by W. Pagel, in Isis, 38 (1948), 248–249.

Helmont’s natural philosophy and chemistry are discussed in H. Hoefer, Histoire de la chimie, 2nd ed., II (Paris, 1869), 134–146; H. E. Hoff, “Nicolaus of Cusa, van Helmont and Boyle. The First Experiment of the Renaissance in Quantitative Biology and Medicine,” in Journal of the History of Medicine, 19 (1964), 99–117: H. M. Howe. “A Root of van Helmont’s Tree,” in Isis. 56 (1965), 408–419, which presents the Gnostic-neo-Clementine source for the experiment with the willow tree; H. Kopp, Geschichte der Chemie, 4 vols. (Brunswick, 1843–1847), I, 117–127; II, 168, 241–243, 273, 344–366: III. 62–190. 227–350; IV, 380; R. P. Multhauf, The Origins of Chemistry (London, 1966), pp. 250–252, 285–286, 294–295. 316, 344: W. Pagel, “Helmont, Leibniz, Stahl,” in Archie fúr Geschichte der Medizin. 24 (1931), 19–59; The Religious and Philosophical Aspects of van Helmont’s Science and Medicine, supp. to Bulletin of the History of Medicine, no. 2 (Baltimore, 1944), see pp. 16–26 on the wider implications of “gas”; “J. B. van Helmont (1579–1644),” in Nature. 153 (1944), 675; “Van Helmont; The 300th Anniversary of His Death.” in British Medical Journal (1945). 1 , 59; “J. B. van Helmont De tempore and Biological Time,” in Osiris, 8 (1949), 346–417; “The Reaction to Aristotle in Seventeenth Century Biological Thought,” in Science, Medicine and History, Essays in Honour of Charles Singer, I (Oxford, 1953), 489–509; “The ‘Wild Spirit’ (Gas) of John Baptist van Helmont (1579–1644) and Paracelsus.” in Ambix, 10 (1962), 1–13: and “Chemistry at the Cross-Roads: The Ideas of Joachim Jungius. Essay-Review of H. Kangro, J. Jungius’ Experimente und Gedanken zur Begründung der Chemie als Wissenschaft,” ibid., 16 (1969), 100–108, includes a discussion of Helmont’s interpretation of the precipitation of copper after the addition of iron to a vitriol solution; J. R. Partington, “Joan Baptist van Helmont,” in Annals of Science, 1 (1936), 359; and A History of Chemistry, II (London, 1961), 209–243; C. Webster. “Water as the Ultimate Principle of Nature: The Background to Boyle’s Sceptical Chymist.” in Ambix, 13 (1966). 96: and H. Weiss, “Notes on the Greek Ideas Referred to in van Helmont’s De tempore,” in Osiris, 8 (1949), 418–449.

Helmont’s work in medicine is treated in H. Haeser, Lehrbuch der Geschichte der Medizin und der epidemischen Krankheiten, 3rd ed., II (Jena, 1881), 344–363: Lester S. King, The Road to Medical Enlightenment, 1650 –695 (London-New York, 1970), pp. 37–62, 88–90; P. H. Niebyl, “Sennert, Van Helmont and Medical Ontology,” in Bulletin of the History of Medicine, 45 (1971), 115–137; W. Pagel, Jo. Bapt, van Helmont. Einfülhrung in die philosophische Medizin des Barock (Berlin, 1930); “The Speculative Basis of Modern Pathology. Jahn, Virchow and the Philosophy of Pathology,” in Bulletin of the History of Medicine. 18 (1945), 1–43; “Van Helmont’s Ideas on Gastric Digestion and the Gastric Acid,” ibid., 30 (1956). 524: “Harvey and Glisson on Irritability With a Note on Van Helmont.” ibid,. 41 (1967), 497–514; “Harvey and the Modern Concept of Disease,” ibid,. 42 (1968), 496–509, written with M. Winder; and “Van Helmont’s Concept of Disease—To Be or Not To Be? The Influence of Paracelsus,” ibid. (in press); W. Rommelaere, “Études sur J. B. van Helmont,” in Mémoires couronnés et autres mémoires p.p. de I’Académie royale de couronnés médecine p.p de Belgique, 6 (1866). 281– 541. reprinted separately (Brussels, 1868); and G. A. Spiess, J. B, van Helmonts System der Medizin verglichen mit den bedeutenderen. Systemen ällerer und neuerer Zeit (Frankfurt. 1840).

Helmont’s influence is the subject in Allen G. Debus, The English Paracelsians (London, 1965), pp. 181–183; and The Chemical Dream of the Renaissance (Cambridge, 1968) pp. 25 ff.: F. N. L. Poynter, “A 17th Century Medical Controversy; Robert Witty and William Simpson.” in E. A. Underwood, ed., Science, Medicine, and History. Essays in Honour of Charles Singer, II (Oxford, 1953), 72–81”; P. M. Rattansi, “The Helmont-Galenist Controversy in Restoration England,” in Ambix, 12 (1964), 1–23; Henry Thomas, “The Society of Chymical Physitians, an Echo of the Great Plague of London,” in Underwood, op cit, 56–71; und C. Webster, “The English Medical Reformers of the Puritan Revolution. A Background to the Society of Chymical Physitians,” in Amhix, 14 (1967), 16–41; “The Helmontian George Thomson and William Harvey: The Revival and Application of Splenectomy to Physiological Research,” in Medical History, 15 (1971), 154–167.”

Walter Pagel

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Helmont, Johannes (Joan) Baptista Van


(b. Brussels, Belgium, 12 January 1579; d. Brussels, Belgium, 30 December 1644),

alchemy, chemistry, controlled experimentation, natural philosophy, medicine, mysticism, quantification. For the original article on Helmont see DSB, vol. 6.

The focal points of modern Van Helmont research are twofold: Van Helmont’s experimental method, and especially the role of quantification in his experimental practice, has undergone closer scrutiny; and his mysticism, more specifically the original place he occupies in the history of mysticism, has provoked novel interpretations. These two trends are discussed below in more detail. It should be stressed that these two aspects—often delineated from each other as the “scientific” and the “non-scientific” or “extra-scientific” aspects of Van Helmont’s work—were two sides of the same coin for Van Helmont. The underlying unity in Van Helmont’s philosophia naturalis has been emphasized in the works of Van Helmont’s main biographer, the German historian Walter Pagel. The study of both trends as well as the insight that they were inseparable for Van Helmont can be seen as fruitful results of Pagel’s arduous work, which paved the way for following generations of historians of science to add further nuance to Van Helmont’s natural philosophy.

Experimental Method . Research has shown that, although Van Helmont’s experimental procedures were

still far removed from modern experimental practice, he contributed significantly to the emergence of experimental practice and reasoning. In Van Helmont’s work, there was not yet a sharp distinction between “an experience” and “an experiment.” In contrast to an experience, an experiment presupposes the involvement of a specific question about nature that the experimental outcome is designed to answer. Van Helmont’s experimental practice also included a broad variety of argumentative strategies in support of naturalistic theses such as anecdotes, histories, loose observations, questioning by fire (i.e. chemical fire analysis, “quaerere per ignem”), and especially mechanical demonstrations (mechanicae probationes). Especially the last two strategies contain the most developed features of his experimental practice. The term “mechanical demonstration” is perhaps somewhat misleading, since to Van Helmont’s mind it was not directly related to simple machines. The Low-German equivalent “handtdadelijcke mechanijcke bewesen,” in other words, “hand-on” or “handicraft,” better illustrates Van Helmont’s notion of a mechanical experiment. Generally, it referred to natural processes that were deliberately manipulated at the hand of the investigator of nature (and is thus not directly connected to simple machines). His scientific practice contained a strong insistence on intervening and manipulating natural processes.

In Van Helmont’s work can be seen the gradual emergence of controlled experimentation. Van Helmont frequently set out to control certain variables while varying others. This method is especially striking in several of his famous experiments: in his experiment with the thermo-scope, where it is shown that if the thermoscope is kept perfectly shut no water can be transformed into air; in his ice-experiment, where he keeps fixed the absolute weight of water in order to infer that the increase in its specific weight can only be due to an internal action of the water itself; and also in his famous willow experiment, where Van Helmont controlled (or at least thought so) the purity of the administered water and the purity of the earth in which the tree grows—all three examples are from Ortus Medicinae (1648). Johann Joachim Becher (1667) and James Woodward (1700) later criticised Van Helmont’s experiment on the grounds that the measurements involved were not precise enough and that not enough variables were controlled.

Van Helmont’s work did not explicitly appeal to certain social conventions—which were clearly present in Robert Boyle’s work—that experimental philosophers should use in dealing with each other and considering knowledge claims. Van Helmont did not engage much in public experimentation. In addition to that, detailed prescriptions, that would allow readers to redo the experiments Van Helmont describes, are also absent in his work. The contrast with Boyle’s careful written accounts of his experiments and air-pumps is striking in this respect. Van Helmont did mention replication and reproducibility rather sporadically but did not insist much on them as criteria of valuable scientific knowledge. Correspondingly, he did not give specific information that allowed one to redo certain experiments. For Van Helmont, an experiment was thus a personal testimony that is not necessarily supposed to be redone by different agents in order to qualify as scientifically valuable. The absence of the stress on replication and reproducibility characteristic of Van Helmont’s experimental practice separates it from modern approaches.

The view that a modest degree of quantification was essential to Van Helmont’s experimental work has gained more support by historians. Van Helmont’s critique of mathematics (abundant in Ortus Medicinae, 1648) should not be interpreted as a rejection of mathematics in toto, only as a careful awareness of the limits of mathematics. According to Van Helmont, mathematics places entities under the praedicamentum quantitatis: It does not succeed in penetrating the essence of things (“wesentheyt”), which is only provided by knowledge of the semina. In similar fashion, Van Helmont argues that because Aristotelian philosophy ignores the semina, it is like a sculptor that skilfully imitates the external shape of a man, but does not know its internal structure. Nevertheless, mathematics is useful for the establishment of scientific propositions (he frequently used the term “demonstratio mathematica” and “mathesis”).

The importance of mathematical arguments in Van Helmont’s work is mainly restricted to determination of weights and density-ratios. For example, Van Helmont’s ordering of the density-ratios of tin (which he used as his standard unit), iron, copper, silver, lead, mercury, and gold differs from the modern ones by only an average of less than 2 percent. Although modern quantitative-like aspects play a role in Van Helmont’s experimental procedures and although he often stressed the mathematical component in his arguments, it would be clearly exaggerated to call Van Helmont’s experimental procedures as quantified as those of the early twenty-first century, in which both the level of accuracy has become more important (because modern means of measurement have expanded drastically) and the mathematics involved has become more complex (for example, the usage of statistics and formulae). Exact values are rarely provided by Van Helmont and values are mostly determined and presented roughly (at least in the published versions).

In his famous willow experiment, the weights of the earth and the willow are determined and compared only roughly. Van Helmont dried approximately 200 pounds of earth, in which he planted a willow (weighing five pounds), and isolated it from the external world by means of a tin plate with small holes, to guarantee that no other elements than earth could enter the pot. The water Van Helmont administered was equally “pure” (i.e., either distilled water or rainwater), so that again no other elements than water could reside in the pot. In contemporary parlance, it would be said that these variables (earth and water) were controlled. After five years the willow was weighed again (now c. 169 pounds). Van Helmont only weighed the “Wood, Barks, and Roots.” Apparently, Van Helmont did not include the weight of the leaves for whatever reason. Notice that Van Helmont is not worried at all by the disappearance of two ounces of earth over the period of time. Given that there did not reside any other elements than earth and water in the pot, and given that the earth did not diminish significantly, Van Helmont (wrongly) concluded that only the administered water produced the additional gain of 164 pounds. Quam proxime was good enough for Van Helmont. He did not have the instrumental means to discover and detect the role of minerals in the growth-process of plants. As Van Helmont strongly believed in the indestructibility of matter, he claimed that the weights of the reagentia during chemical reactions are unalterable.

In the establishment of his experimental natural philosophy, Van Helmont succeeded in breaking with the dichotomy between art (articificialia) and nature (naturalia): In manipulating natural processes nature’s modus operandi remains the same. Hence, the art of fire is a legitimate source of objective knowledge of nature. It is by manipulating nature (naturae operationes mutando) in an experimental way that one succeeds in establishing science.

Mysticism . According to Van Helmont, who explicitly aligned himself with hermetic and Pythagorean philosophies, the world humans experience is but a sign (signatum) of the hidden spiritual world behind it. The Aristotelian school stopped at the external façade and therefore reached only superficial knowledge about the external world. Van Helmont believed that there are two ways of obtaining true knowledge about the creation: One was to study nature by experiments, in which the experimenter indirectly communicates with God; the other was mysticism, in which direct communication with God’s workings is attained. It should be stressed that Van Helmont saw these ways as intimately connected. Experiments demonstrated the working forces, i.e. the spiritual archei, which produce natural phenomena. Mystical experience equally allowed penetrating the deeper spiritual significance of nature. It should be noted that Van Helmont’s mysticism is quite different from traditional mysticism (such as that developed by Thomas à Kempis whom Van Helmont highly respected) in which the mystical unity (unio mystica) is mostly associated with experiencing the divine being. For Van Helmont, the object of mystical experiences was far more mundane: It involved questions relating to scientific, chemical, and medical phenomena. The objects of Van Helmont’s mystical experiences were “mystified” natural phenomena, i.e. substances he manipulated by alchemical operations and contemplated correspondingly. This is a striking aspect of Van Helmont’s mysticism. Van Helmont, then, was not only a reformer of natural philosophy, but also a reformer regarding spiritual experience.


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Steffen Ducheyne

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