Sennert, Daniel

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(b. Breslau, Germany [now Wroclaw, Poland], 25 November 1572; d. Wittenberg, Germany, 21 July 1637).

medicine, chemistry.

Sennert was the son of a shoemaker, Nicolaus Sennert, and Catharina Helmania, both of whom came from Silesia (from Lähn and Zopten, respectively). After attending the schools in his native Breslau, Sennert enrolled at the University of Wittenberg on 6 June 1593. He followed the basic course of study in the philosophy faculty and was awarded the master’s degree on 5 April 1598. He originally intended to become a teacher, but studied medicine instead for three years at the universities of Leipzig, Jena, and Frankfurt an der Oder. In 1601 he entered medical practice in Berlin under the supervision of the physician Johann Georg Magnus. After a short stay at the University of Basel, he obtained the doctor of medicine degree from Wittenberg on 10 September 1601. Altering his plans immediately to open a medical practice, he successfully sought the professorship of medicine at Wittenberg, which he was named to on 15 September 1602 and held until his death.

In 1603 Sennert married Margarethe Schatt of Wittenberg, by whom he had seven children. One of them, Andreas, became a famous Orientalist. Margarethe died in 1622 and in 1624 Sennert married Helene Burenius of Dresden. Following her death, Sennert married, in 1633, Margarethe Kramer of the principality of Sachsen-Altenburg. The last two marriages were childless. Sennert died from what was diagnosed as “plague,” after he himself had survived six epidemics of the disease while serving as physician in Wittenberg.

Sennert was a well-known teacher, physician, and scientific writer. His medical ideas have never received a thorough treatment, although his publishing activity began1 in 1611 with the lengthy Institutionum medicinae libri V and continued with other large works on medicine, such as De febribis libri IV of 1619 and Practicae medicinae, which appeared successively in six books between 1628 and 1636. Closely related to these works were others in which he dealt in detail with chymia, a subject that had been placed in the service of medicine by Paracelsus. This group began with the revealingly titled De chymicorum cum Aristotelicis et Galenicis consensu ac dissensu liber I (Wittenberg, 1619). Sennert’s views are generally difficult to judge, because he attempted to reconcile the theories of Aristotle, Galen, Paracelsus, and the supporters of the traditional atomic hypotheses. For this reason Lasswitz judged Sennert too one-sidedly from the point of view of atomism, while Thorndike and Partington gave equally distorted assessments, but from the standpoints, respectively, of magic and modern chemistry. Even Ramsauer’s attempt to describe Sennert’s amalgamation of the various doctrines remained incomplete, in part because he lacked sufficient knowledge of the requisite languages.2

In medicine, Sennert defended Galen’s humoral pathology. From the three Paracelsian principles, sulfur, salt, and mercury, he derived, like Jean Béguin, properties suitable for the chemical treatment of disease. Sennert thought that sulfur, which he considered to be to be the principle of burning, “phlogiston” (1619), was responsible for the heat of the heart. Salt supposedly served as the radical of the liver, and mercury as the spiritual principle of the brain. Sennert assumed that these three principles cannot be isolated; otherwise, their medicinal properties would be destroyed—an opinion still held in 1662 by Robert Boyle with respect to chemical action.3 Sennert broke with Paracelsus, however, in rejecting the macroscopic influence of the celestial bodies. He also rejected Paracelsus’ view that diseases are caused by the ens deale, ens astrale, ens naturale, ens spirituale, and ens veneni.4 Further, unlike Paracelsus, Sennert thought that the tria prima are actually prima mista (first combinations), specifically, that they are composed of the four Peripatetic elements. He agreed with Paracelsus, however, that all natural bodies contain a vis seminalisthat bestows life on them (and that, for example, causes the growth of metals). He joined this seminal force in a Neoplatonic fashion with the logos to produce a principium plasticum (formative principle).

From the above, it is obvious how strongly rooted the academic physician Sennert was in the ancient tradition. Even where he conceived from a corpuscular point of view the constituents joined together under the form, he retained the Peripatetic notion of form (which is independent of celestial influence).

In the theory proper of change in natural processes—which includes what we call “chemistry”—Sennert followed to some extent the views of the physicians Jean Fernel and Ibn Sïnä, according to whom the forms of the constituents persist under the new forma superior of the mixtum (for example, of the chemical compound) (1629). In 1619 Sennert, still following Ibn Rushed in this respect, held that the parts of the form persist and therefore that the form persists as such individually: eadem numero. Notwithstanding, in order to allow the new natural body (mixtum) to come into being, Sennert posited the existence of an impetus(natura, ópµń), which functions as a causal force. This is in addition to the spiritus architectonicus, which first creates the new forms, but then also the occult forms (or properties, as stated in the writtings of Fernel). Sennert also retained until at least 1636 the notion he took from Albertus Magnus and Jacopo Zabarella of a multiplication of the forms responsible for the properties.

The fact that Sennert, like Ibn Sī n ā, assumed the persistence of the forms of the constituents was made easy for him by notions dominant in the medical tradition since the time of Galen (for example, in the interpretation of the analysis of milk). To be sure, Sennert did not think it necessary to prove this theory through an actual separation of the constituents. This is evident from his theory of the elements. On the basis of J. C. Scaliger’s principle, as in essendo, so in causando, Sennert inferred, in a direct, a posteriori manner, the existence of the four Peripatetic elements and the three Paracelsian principles from the perceptible properties of substances. For Sennert, as for Aristotle, this reasoning sufficed as a demonstration of the existence of the elementary constituents. The constituents must, of course, already be present in the body potentia, that is to say, with respect to their possible effect. Otherwise the formations of the new body (mixtum) would not be a qualitative change (alteratio) but a destruction or new creation. Combustibility, for example, demonstrates that the principle “sulfur” does have an effect. Sennert held that it was the concern of the wise, not of the common people, to discover these basic conceptions (the elements and the tria prima).

Sennert’s fundamental principle of analysis was: ex ü corpora naturalia constant, in quae resolvuntur (“nature bodies consist of that into which they are decomposed”). He also correctly inverted this proposition, which, incidentally, he attributed to Hippocrates. He felt that he was faithful to the medical tradition not only in adopting this proposition, but also in accepting Galen’s definition of the elements as very small particles (minima). In order to arrive at the elements, he added–true to the Aristotelian tradition–the necessity of the ultima resolution (1635). In his view, the prima mista combined from the elements are the direct causes of the perceptible properties (Prima qualitates: color, taste, smell). Thus, sulfur gives rise to the ability to burn and to smell, and salt to crystallization and to taste. Sennert was not sure what properties to assign to mercury.

Sennert held that the mechanism of reaction consisted of two stages: (1) the bodies split up into minimae particulae; (2) they then move about and reform as a new body. Although Sennert referred to a corresponding definition of Scaliger’s, Galen had already put forth the idea of the comminution and reciprocal action of the fragments. The end product is no mere assemblage of the particles: rather, its properties are determined by the natura quinta associated with the form. In 1619 Sennert named this comminution and recombination diacrisis and syncrisis, respectively. (For Jungius’ different terminology, see the article on him in this Dictionary.) A novel element in this account is that Sennert, an Aristotelian, went beyond the concepts of actio (influence) and passio (being influenced by) and raised the question of a re-actio and re-passio, perhaps on grounds of symmetry.

Sennert made use of an atomic theory properly so-called only in certain cases where he wished to show the persistence of the nature of a substance (1629). Specifically, he adopted this point of view in discussing distillation, sublimation, coagulation, the melting of the gold-silver alloy, and the solution of silver in nitric acid and of common salt in water. It was not until 1636, however, that he spoke of the unalterable persistence of the particles themselves.

Between 1611 and 1636 Sennert developed a compromise atomic hypothesis starting from the assumptions of the Averroistic school of Padua.

At first sight it appears surprising that in 1624 Sennert argued (falsely) for a transmutatio (that is. genuine transformation) of iron into copper during precipitation. He held that since many authors had confirmed it, it was a waste of time to continue the dispute.

For Sennert (as for A. G. Billich) chemistry is not an auxiliary art, but has its own inner goal (finisinternus, 1629): to decompose natural substances and to prepare them for use. It thus possesses an independent character. Its external goals are healing and the metamorphosis of metals. An academic physician, Sennert incorporated the craft chymia into scientific medicine. First one conducts chemical experiments; the reasons that account for them will not fail to be discovered. In 1629 he stated that both medicine and chemistry must, because they are parts of a single knowledge of nature, seek to discover natural laws in such a way that the doctrine of nature (Physica) supplies chymia with the theory of natural principles, whereas chymia furnishes Physica with the experience acquired from chemical operations.


1. Robert Multhauf, The Origins of Chemistry (London, 1966). 265. n. 27: and H. Kangro. Joachim Jungius’ Experiment und Gedanken zur Begründung der Chemie als Wissenschaft (Wiesbaden, 1968). R. Hooykaas devotes a chapter to Sennert’s chemical procedures in Het begrip element in zijnhistorische–wijsgeerige ontwikkeling (Utrecht, 1933), 160–167.

2. Kangro, op. cit., 144.

3. R. Boyle, The Sceptical Chymist, conclusion.

4. Multhauf, op. cit., 265, notes that these entia are five in number, as are the eternal substances of al-RāzĪ. It may be added that the notion of the natura quinta appeared in the third century B. C. and that Ētienne da Clave (1624) employed five principles: tria prima, phlegma, caput mortuum.


I. Original Works. There does not exist a complete bibliography of Sennert’s works; some are listed in the catalogs of the Bibliothèque Nationale, Paris, and of the Library of the British Museum. See also J. R. Partington, A History of Chemistry, II (London-New York. 1961), 271–272; H. Kangro, Joachim Jungius’ Experimente und Gedanken zur Begründung der Chemie als Wissenschaft (Wiesbaden. 1968), 407: the tiltes given in Biographisches Lexikon der hervorragenden ärzte aller Zeiten und Völker, A. Hirsch, E. Gurlt, and A. Wernich eds., 2nd ed., V (Berlin—Vienna, 1934), 230, are not very exact.

The main works are Epitome naturalis scientiae, comprehensa disputationibus viginti sex, in...Academia Witebergensi...propositis a M. Daniele Sennerto (Wittenberg, 1600) (I have not seen this); Institutionum medicinae libri V. (Wittenberg, 1611);Disputatio medicina, qua suam de occultis, seu totius substantiae quasvocant morbis sententiam defendit D. Sennertus ([Wittenberg], 1616); Epitome naturalis scientiae (Wittenberg, 1618), including atomism, most probably for the first time and so different from the disputations in 1600; De chymicorum cum Aristotelicis et Galenicis consensu ac dissensu liber I (Wittenberg, 1619); De febribus libri IV (Wittenberg, 1619); De scorbuto tractatus (Wittenberg, 1624); De dysenteria tractatus (Wittenberg, 1626); Disputatio physica de gustu et tactu (Wittenberg, 1626); Disputatio physica de auditu et olefactu (Wittenberg, 1626); Practicae medicinae, liber I, II, III, IV, V, VI (appeared at different places from 1628 till 1636): De chymicorum cum Aristotelicis et Galenicis consensu ac dissensu liber: cui accessit appendix de constitutione chymiae (Writtenbesrg, 1629), very different from the work ed. in 1619; De arthritide tractatus (Wittenberg, 1631); Epitome institutionum medicinae (Wittenberg, 1631); Epitome librorum de febribus (Wittenberg, 1634); Hypomnemata Physica (Frankfurt am Main, 1636); Paralipomena cum praemissä methodo discendi medicinam, tractatus posthumus (Wittenberg, 1642); Sennertus (Daniel). Culpeper (Nicholas), Cole (Abdiah), Thirteen Books on Natural Philosophy (London, 1660).

A work of unknown authorship (see Kangro [1968], pp. 126–127, note 178) is Auctarium epitomes physicae... Danielis Sennerti (edited simultaneously at Wittenberg and Hamburg, 1635).

Moreover Sennert has written many Disputationes, which still wait to be revealed among the occasional writings of various authors bound together in volumes of the seventeenth century.

II. Secondary Literature. No full presentation of Sennert’s life and work is known. Biographical details are included in the works of August Buchner. Dissertationum Academicarum volumen II (Wittenberg. 1651); J. Graetzer, Lebensbilder hervorragender schlesischer Arzte (Breslau, 1889); and Allgemeine Deutsche Biographie, R. V. Liliencron and F. X. von Wegele, eds., published by the Historische Commission bei der Königlichen Akademie der Wissenschaften (at Munich). XXXIV (Munich-Leipzig, 1892), 34–35.

On chemical views of Sennert, consult Reijer Hooykaas (1933: see note 1), 160–167; J. F. Partington, A History of Chemistry, XXIII (London, 1961), 271–276; Robert P. Multhauf (1966: see note 1), passim; Hans Kangro (1968: see note 1), passim; Allen G. Debus, “Guintherius, Libavius and Sennert: The Chemical Compromise in Early Modern Medicine,” in Science, Medicine and Society in the Renaissance, A. G. Debus, ed. (New York, 1972), 157–165, and “The Paracelsians and the Chemists: the Chemical Dilemma in Renaissance Medicine,” in Clio medica, 7 (1972), 195. Sennert’s atomism is particularly treated by Kurd Lasswitz, “Die Erneuerung der Atomistik in Deutschland durch Daniel Sennert und sein Zusammenhang mit Asklepiades von Bithynien,” in Vierteljahrsschrift für wissenschaftliche Philosophie, 3 (1879), 408–434; idem, in Geschichte der Atomistik vom Mütelalter bis Newton, 2 vols. (Hamburg-Leipzig, 1890), vol. 1 436–454 and passim in vols. I and II ; and Rembert Ramsauer, Die Atomistik des Daniel Sennert (Kiel, 1935), the last not always reliable.

A few thoughts extracted from Sennert’s large medical work are briefly dealt with by Walter Pagel, “Daniel Sennert’s Critical Defence of Paracelsus,” in Paracelsus, An Introduction to Philosophical Medicine in the Era of Renaissance (Basel-New York, 1958), 333–343; “William Harvey Revisited,” in History of Science, 8 (1969), 10, and 9 (1970), 7, 11–20; and Peter H. Niebyl, “Sennert, van Helmont, and Medical Ontology,” in Bulletin of the History of Medicine, 45 (1971), 115–137.

On older sources dealing with views of Sennert, see Ferguson.

Hans Kangro

Sennert, Daniel

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(b. Breslau, Germany [now Wroc aw, Poland], 25 November 1572; d. Wittenberg, Germany, 21 July 1637), medicine, chemistry. For the original entry on Sennert see DSB, vol. 12.

Since Hans Kangro wrote his entry for the original Dictionary of Scientific Biography, a number of new facts have emerged about Daniel Sennert that both nuance his biography and add substantially to the knowledge of his influence in the early modern scientific community. First, Sennert seems to have received virtually his entire education at the University of Wittenberg. His multiple publications stemming from Wittenberg in the period between 1596 and 1601 show the unlikelihood of Sennert’s having spent three years attending the Universities of Leipzig,

Jena, and Frankfurt during this period, as has been claimed. This fact is interesting in that it underscores the high degree to which Sennert was a hothouse product of the University of Wittenberg, molded and encouraged in his scientific interests by his mentor, the professor of anatomy Johann Jessenius.

Second, it is now clear that Sennert was already a self-styled atomist by 1619, the year that he published his De chymicorum cum Aristotelicis et Galenicis consensu ac dissensu. Kangro, along with various other scholars, was misled by Sennert’s publication of his non-atomistic Epitome naturalis scientiae only the year before. But Sennert explicitly ranked the Epitome among his juvenilia in the preface, and pointed out that he was publishing it only as an introductory school text. Most scholars have overlooked Sennert’s clear alliance with Democritean atomism already in the De chymicorum and in private communications with Michael Döring from the early 1620s. Despite his self-styled Democritean allegiances, however, Sennert’s atomism was a combination of alchemical corpuscular theory derived from the medieval writer Geber and his followers, more modern Paracelsian notions transmitted by the chymical polemicist Andreas Libavius, Aristotelian meteorological theory culled mainly from Book 4 of the Stagirite’s Meterology, and neo-Aristotelian currents stemming largely from the extraordinarily influential work of Julius Caesar Scaliger. This is not to say that Sennert was an eclectic, however, as is often claimed in the secondary literature. Sennert’s atomism reveals a striking coherence and integration with laboratory practice. His habit of citing multiple sources is both a diplomatic attempt to arrive at consensus and an example of the early modern need to ground novelty in tradition.

Perhaps the most significant component of Sennert’s atomism was its experimental basis. Developing ideas that were already present in earlier alchemy, Sennert argued that the tria prima of Paracelsian chymistry, mercury, sulfur, and salt, were principles (literally, beginnings) precisely in the sense that they were the products revealed by fire analysis. Because they were the final results of analysis, they could be viewed as prima mixta (first mixts), the primitive bodies out of which nature ordinarily composes more complex mixtures. This analytical ideal was based on a negative-empirical concept that located the physical principles of more complex materials in the limits of the technical analysis that could be carried out in a chymical laboratory. The a posteriori approach that Sennert applied to the determination of material components was adopted by subsequent chymists such as Joan Baptista Van Hel-mont and Robert Boyle, who would transmit this methodology to the chemical reformers of the eighteenth century even as they expressed their doubts about the universality and simplicity of the three principles.

A particularly important feature of Sennert’s atomism lay in his polyvalent use of the so-called reduction to the pristine state (reductio in pristinum statum), a type of experimental demonstration that he used to combat the theories of perfect Aristotelian mixture advocated by the followers of Thomas Aquinas and John Duns Scotus. The Thomistic and Scotist mixture theories prevalent in early modern universities denied the persistence of the substantial forms of the initial ingredients in a mixture. This meant that if two substances were to undergo Aristotelian mixis, it should not be possible to recapture them intact, because their forms had been destroyed in the process of mixing them. The imposition of the new substantial form of the mixture was supposed to replace the individual forms of the ingredients. But what if an opponent could show that seemingly homogeneous mixtures that appeared to be so-called perfect mixts actually retained their ingredients unchanged, though hidden to the senses? Such a demonstration would forcibly throw doubt on the theory of perfect mixture itself, because the criterion of visual homogeneity could no longer be trusted to reveal the composition of materials.

Sennert exploited this possibility with great zeal, showing that mixtures of metals dissolved in strong acids could be made to yield up their ingredients intact, despite their apparent homogeneity. Employing well established metallurgical and chymical processes, Sennert was able to show that, in the case of silver dissolved in aqua fortis (nitric acid), the original silver could indeed be regained intact, merely by adding salt of tartar to the solution. An intermediate step where the metal-acid solution was filtered added additional force to the demonstration by revealing that the silver had to have been broken into particles small enough to pass through the pores of the filter paper. That these corpuscles were sufficiently robust to resist the analytical power of the acid, coupled with their small size, fulfilled the canonic requirements of atomism and showed that even a combination as seemingly homogeneous as a metal dissolved in acid could not really be a perfect mixture in the Aristotelian sense.

Sennert’s reductions to the pristine state would have great influence on the following generation. Boyle, whose name is synonymous with the mechanical philosophy, used Sennertian reductions to the pristine state to demonstrate the existence of atoms in his juvenile, unpublished Essay Of the Atomical Philosophy, whereas his mature Sceptical Chymist elaborated on these demonstrations to argue for the reality of robust, complex corpuscles. Boyle also reinterpreted the reduction to the pristine state so that it became a demonstration of the mechanical origin of qualities, hence obviating the need for substantial forms. Because Boyle did not acknowledge his considerable debt to Sennert, his use of the German academic’s atomism has until recently gone largely unnoticed. Sennert’s other areas of contribution, particularly in the realms of medicine and theology, require further study, but it is likely that here too his influence has been undervalued.



Epitome naturalis scientiae, comprehensa disputationibus viginti sex.

Wittenberg, Germany: Simon Gronenberg, 1600. Although Kangro knew of this text, he had not seen it; since then most of the twenty-six disputations, which were published separately and then collected under a separately printed title-page, have been located in the Bibliothèque nationale (Paris). Despite the similarity in title of the 1600 Epitome and that of 1618, the two works are very different. The 1600 Epitome consists of Dissertations printed for oral defense, written before Sennert developed any significant interest in chymistry.

De chymicorum cum Aristotelicis et Galenicis consensu ac dissensu.Wittenberg, Germany: Zacharias Schurer, 1619.


Lüthy, Christoph, and William R. Newman. “Daniel Sennert’s Earliest Writings (1599–1600) and their Debt to Giordano Bruno.” Bruniana & Campanelliana6 (2000): 263–279.

Lüthy, Christoph. “Daniel Sennert’s Slow Conversion from Hylemorphism to Atomism.” Graduate Faculty Philosophy Journal 26 (2005): 99–121.

Meinel, Christoph. “Early Seventeenth-Century Atomism:Theory, Epistemology, and the Insufficiency of Experiment.” Isis79 (1988): 68–103.

Michael, Emily. “Daniel Sennert on Matter and Form: At the Juncture of the Old and the New.” Early Science and Medicine 2 (1997): 272–299.

———. “Sennert’s Sea Change: Atoms and Causes.” In Late Medieval and Early Modern Corpuscular Matter Theories, edited by Christoph Lüthy, John E. Murdoch, and William R. Newman. Leiden, The Netherlands: E.J. Brill, 2001.

Newman, William R. “The Alchemical Sources of Robert Boyle’s Corpuscular Philosophy.” Annals of Science 53 (1996): 567–585.

———. “Art, Nature, and Experiment Among Some Aristotelian Alchemists.” In Texts and Contexts in Ancient and Medieval Science: Studies on the Occasion of John E. Murdoch’s Seventieth Birthday, edited by Edith Sylla and Michael McVaugh. Leiden, the Netherlands: Brill, 1997.

———. “Corpuscular Alchemy and the Tradition of Aristotle’s Meteorology, With Special Reference to Daniel Sennert.” International Studies in the Philosophy of Science15 (2001): 145–153.

———. “Experimental Corpuscular Theory in Aristotelian Alchemy: From Geber to Sennert.” In Late Medieval and Early Modern Corpuscular Matter Theories, edited by Christoph Lüthy, John E. Murdoch, and William R. Newman. Leiden, The Netherlands: E.J. Brill, 2001.

———. “Robert Boyle’s Debt to Corpuscular Alchemy.” In Robert Boyle Reconsidered, eds. Michael Hunter. Cambridge, U.K.: Cambridge University Press, 1994.

———, and Lawrence M. Principe. Alchemy Tried in the Fire:Starkey, Boyle, and the Fate of Helmontian Chymistry. Chicago: University of Chicago Press, 2002.

Stolberg, Michael. “Particles of the Soul: The Medical and Lutheran Context of Daniel Sennert’s Atomism.” Medicina nei secoli15 (2003): 177–203.

William R. Newman

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