Instrument transfer as knowledge transfer in neurophysiology:
François Magendie's early attempts to measure cerebrospinal fluid pressure
Frank W. STAHNISCH
François Magendie's (1783-1855) experimental model to measure blood pressure in animals had a major impact on the development of 19th-century-French physiology. It was based on the empiricist view that hydraulic models and physical analysis had a legitimate place in physiological research. Magendie's experimental paradigm was soon received by other European physiologists, such as Carl Ludwig (1816-1895) and Jules Marey (1830-1904), as well as by clinicians who developed it into a major measuring technique for blood pressure during the later half of the 19th-century.
Yet, hardly any attention has been paid by historians of science and medicine to Magendie's further investigations conducted with the help of Jean-Louis Marie Poiseuille's (1799-1869) sphygmometer developed in 1828: After having used the apparatus to experiment on a variety of blood vessels, Magendie applied the sphygmometer to the ventricular system to measure cerebrospinal fluid (CSF) pressure. The scope and limit of this new procedure, however, still had to be defined. The new measuring device invited many speculative interpretations regarding the meaning of CSF flow in the physiology of the ventricular system as well as in terms of the state of brain function in normal life and psychic illness. Magendie's experiments produced phenomena in very heterogeneous knowledge spaces, and CSF measurement was situated at the interface of disparate investigative perspectives on brain structure and function.
Magendie's constitutive work on the subject began with an experimental shift: In his 1840/41 Leçons sur les fonctions et les maladies du système nerveux, he describes the application of the measuring "apparatus of Poiseuille" from blood vessels to parts of the brain. The instrument really became a sort of liquordynamometer. In the explorative manner of Magendie's experimental setting, this liquordynamometer led to new scientific interpretations and paved the way for diagnostic intracranial pressure (ICP) measurement by Theodor Kocher (1841-1917) or Harvey Cushing (1869-1939). My paper will focus on the epistemological contingencies that prompted the instrument transfer in Magendie's laboratory.
Session XI -- Scientific Methods and Metaphors
Los Angeles, California, USA