Biographies de neurologues
Nouvelle Iconographie de La Salpêtrière
 L'histoire des neurosciences à La Pitié et à La Salpêtrière J Poirier
The history of neurosciences at La Pitié and La Salpêtrière J Poirier 

mise à jour du
15 août 2010
Felicis Mosca
De Oscitatio, De Pandiculatione
Tractatus physico-medicus in homine
Theodorus Craanen (1620-1690)
Traité de l'Homme. René Descartes 1664
La médecine statique. Santorio 1634
Sylvius Delboë 1681
C Bontekoe 1698


La première édition fut publiée en 1689. Dans la lignée de Jacobus Sylvius (Jacques Dubois d'Amiens 1478-1555), Theodorus Craanen fut professeur de médecine à Leyde (Pays-Bas). Raisonnant en cartésien, il décrit dans ce livre la théorie des ferments et compare le corps à une horloge pour expliquer ses fonctions.
theodorus Craanen
CRAANEN (Theodorus), of Kranen, was physician and Doctor of Philosophy and was appointed in 1655 professor of philosophy at the (first) university in Nijmegen, from which he in 1670 moved to his appointment as professor of Philosophy and Mathesis Universalis at the University of Leiden, and as administrator of the Staten Collegie in the same town.
However, his zeal to defend the doctrine of Descartes and the controversy this caused with his colleague professor Spanheim gave curators, in 1673, the chance to dismiss him from both professorships and to appoint him as professor of medicine instead.
In this capacity he served the University of Leiden until the year 1687, when he, at the invitation of Frederick William, Elector of Brandenburg, left for Berlin where he was appointed as first physician. Here he died in 1690 (according to others the 27th March 1688).
His portrait was made by A. Blooteling (1640-1690) (below). He is the author of many books on different topics, released separately, but published completely in Antwerp in 1689. 4o. Two parts.
The liveliness of his wit and disourse are praised, but of his knowledge of medicine and his less thoughtful application of Descartes' philosophy we receive less favourable testimony, although this opinion comes from Herman Boerhaave, whose dislike of Descartes' theory is well known and which has probably influenced this negative testimony.
During his stay in Holland he published: Tractatus Physico-Medicus. of which its 107th chapter deals with 'De Musica', the 108th 'De Echo' and 109th 'De Tarantula'. A new edition of this work appeared in Naples, 1722, 4o.
theodorus Craanen
Theodoer von Craanen by Abraham Blooteling
Sinebrychoff Art Museum
32.60 cm x 22.70 cm
copper engraving
theodorus Craanen
theodorus Craanen
theodorus Craanen
theodorus Craanen
Medicine and The Cartesian Image of Man
Henk Ten Have
Theorical Medicine
At first Descartes' philosophy exerts a direct influence on a number of Dutch physicians, as well as a 17th century current in medicine, known as the iatrophysical school. That Dutch medicine temporarily has been affected by Cartesianism is no coincidence since Descartes lived in Holland for twenty years, moving about from place to place (e.g. Amsterdam, Utrecht, Leiden). Henricus Regius dit Henry Le Roy (1598-1679), professor at Utrecht university, was Descartes' best-known medical follower in Holland, although later on they are not on the best of terms about the problem of relation between body and soul.
In an anonymously published pamphlet entitled Explicatio mentis humanae (1647), Regius explains his view that a human being is an ens per accidens: The soul is not a substance like the body, but modus corporis: As long as it is in the body, the soul is anima organica, i.e. not really distinct from the body. Descartes answers the "insults" of Regius in his Notae in Programma (1647) and also in a letter to the Abbé Picot, the translator of his Principia Philosophiae. He objected to Regius that "it is not an accidental feature of the human body to be joined to a soul, but its very nature".
One of Regius' pupils is Theodoor Craanen (1621-1689), who first works as a professor of logic and metaphysics in Leiden, but is offered later on, after discords on his Cartesianism with colleagues and students, the position of professor of medicine because this is considered less dangerous. Craanen's contribution to medicine has been of a theoretical nature; he neglects instruction at the sick-bed. He is interested in physical functions and their mechanical explanation.
In Oeconomia animalis (1685) he develops the theory that the movement of particles in the vessels and pores of organs is essential for health. Posthumously his writing Tractatus physico-medicus de Homme is published (1689), the mere title of which strongly makes one think of Descartes' Treatise of Man, of which, for that matter, Florentius Schuyl, a predecessor of Craanen in Leiden, has provided, although in Latin, the first publication in 1662.
In the first chapter Craanen makes clear that he prefers to follow the same method as Descartes. He compares the human body with a clock, the organs with its wheels and the blood and animal spirits with the weights. The harmonious functioning of the organism, the 'oeconomia animalis', is explained from the corpuscular structure of the body and the movement of the component particles. Digestion for instance is explained by the laws of mechanics: The food eaten falls apart into numerous tiny parts of different sizes. The alimentary organs contain pores of different shapes. Every particle disappears through a congruent opening and thus reaches the tissue it is meant for: What is good for bone, is transported to the bones, what is good for flesh to the muscles. Disease is caused when particles block up pores that are too small or have the wrong shape. Similar conceptions we find with Blankaart and Bontekoe, pupils of Craanen's who elaborated a mechanistic pathology.
The importance of Craanen's conceptions does not lie so much in this pore-theory (which, for that matter, we also find in Descartes himself), as in his mechanical explanation of physical functioning. This way of explaining things also came into vogue among physicians that had been less directly influenced by Descartes. The theory of blood circulation, described by Harvey in 1628, enormously benefited the mechanical interpretation of the body. The conception of liquid flowing through a closed tube-system was an incentive to consider the body a 'machina hydraulica pneumatica' (in Borelli's words).
There even originated a iatrophysical school in 17th century medical science, which explained physical processes in health and illness exclusively in mechanical or mathematical terms. The origin of this school is to be found at Padua university, where under Galilei's influence the physician Santorio (1561-1636) worked out the idea that number, weight and size are of more importance to the explanation of the functioning of the physical organism than are Galenic qualities such as cold-warm and dry-humid. Santorio developed various instruments to quantify physical functions, among other things the 'pulsilogium', a kind of pendulum with which one can measure the pulse-rate. The same striving for objectivation of physical functions can be found with other physicians from Padua, such as William Harvey, who wrote his dissertation in 1602, and Henricus Regius, who was one of Santonio's pupils.
It was through this counting and measuring that Harvey found the proof for the theory that blood circulates through heart and vessels. The influence of natural scientific thinking also reaches two other representatives of iatrophysics: Alphonso Borelli (1608-1679) and his pupil Lorenzo Bellini (1643-1704). In 1680 the former presented in De motu animalium a theory of the mechanics of muscular functioning with detailed computations of muscular strength.
Indirectly and in the long run the influence of Cartesianism on medical science has been much greater however. Descartes' project of establishing a framework of positive and true knowledge has become a model for any endeavour to acquire scientific knowledge. It has also become determinative for scientific principles as such. Further, Descartes' thinking leads to a fictional way of thinking with respect to the human body as an automatic machine. Cartesianism implies an optimistic view on the development of human knowledge, with the explicit promise of great progress in the field of medicine. These three points can be explained as follows.
The first rule of method which Descartes formulates in the second part of the Discourse on the Method reads: "Accept nothing as true which I did not clearly recognize to be so: that is to say, to avoid carefully precipitation and prejudice, and to accept nothing in my judgements beyond what presented itself so clearly and distinctly to my mind, that I should have no occasion to doubt it".
Descartes' starting point is a fundamental distrust of empirical truths, our own body included, and therefore also of our sensorial capacity to discover that truth. In a process of doubt towards methods generally applied Descartes withdraws to the Ego, the capacity of thinking itself, as a last autonomous position set apart from the beliefs of which the Ego has dissociated itself.
Descartes's basic aim is not to discover only the truth: He is trying to find the indubitable truth. In this pursuit of certainty, the only thing certain and indubitable is the subject, which, while observing, thinking and speaking forms a conception of the world outside. Consequently the world which originally contains the knowing subject itself has become a world of objects, an objective reality placed apart from the subjct and knowledge has become an activity of the Ego, the first person singular.