Avi Ohry
Tel Aviv, Israel

Non-medical scientists and scholars often contribute substantially to medicine. Nicolaus Cusanus (1401–1464), also known as Nicholas of Cusa and Nikolaus Krebs von Kues, was a German cardinal of the Roman Catholic Church, philosopher, jurist, mathematician, and astronomer. In Padua he earned a doctorate in canon law in 1423. He became a close friend of Paolo dell Pozzo Toscanelli (1397–1482), who was a mathematician, astronomer, and physician who provided maps of routes to the New World to Christopher Columbus.¹

Cusanus’ ideas anticipated those of Nicolaus Copernicus and Johannes Kepler. He wrote on Christian Platonism, time and material, eternity, church reformation, logic, and more. His De Docta Ignorantia (“learned ignorance”) and Coincidentia Oppositirum (“coincidence of opposites”) are the key concepts in his philosophy. He was influenced by William of Occam, and he influenced Giordano Bruno and Paracelsus. In his Idiota de Staticis Experimentis, he described the significance of weighing the chemical elements. Less well known are his ideas regarding medicine.

In his Fitzpatrick Lecture of 1905, Dr. Norman Moore said:

In medicine he [Cusanus] introduced an improvement which in an altered form has continued in use to this day. This improvement was the counting of the pulse which up to his time had been felt and discussed in many ways but never counted … Nicholas of Cusa proposed to compare the rate of pulses by weighing the quantity of water run out of a water clock while the pulse beat one hundred times. … The manufacture of watches with second-hands has since given us a simpler method of counting, but the merit of introducing this useful kind of observation into clinical medicine belongs to Nicholas of Cusa.^2,3

Counting the pulse rate with the aid of the clock was an innovation in the history of medicine.

The changing use of the clock metaphor serves as a helpful contrast medium to highlight the different concepts of the body-soul-system between 1450 and 1750. This article first relates to the social, political and philosophical functions of the horologium. Then it outlines the different fields of discourse, in which the clock metaphor was mainly invoked. Finally, it examines the writings of a number of significant authors (Cusanus, Ficino, Descartes, Leibniz, Wolff, La Mettrie) with an eye to the evolution of the clock metaphor in various theological, metaphysical and physiological contexts. Surprisingly enough, the clock (or watch) initially represented the life-giving soul and human consciousness, before turning into the well-known symbol for the body-machine, and in particular for its neurophysiological operations.⁴

Cusanus dealt also with vision and lenses⁵:

Deformation phosphenes are light sensations evoked by deformation of the eyeball in total darkness. … The literature on this topic is discussed, comprising the contributions of the Arabic philosophers and physicians of the 9th and 10th centuries A.D., the Franciscan and Dominican philosophers of the 13th century, Nicolaus Cusanus of the 15th century, several anatomists of the 16th and 17th centuries, Kepler, Plempius, Descartes, Boyle, Newton and others.⁶

Cusa published his works in Martin Flach the Younger’s publishing house in Strassburg (1488 and 1490). Flach also printed the first textbook on gynecology and midwifery, Der Rosengarten (The Rose Garden), written by Eucharius Rösslin (c. 1470–1526), which became a standard medical text for midwives.

References

1. Corsini A. “Paolo Dal Pozzo Toscanelli, physician.” Riv Stor Sci Mediche Nat, 1956; 47(2):361-80.
2. Moore N. “The history of the study of medicine in the British Isles: The Fitzpatrick lectures for 1905-6 delivered before the Royal College of Physicians of London.” London School of Hygiene & Tropical Medicine Library & Archives Service. Oxford: Clarendon Press, 1908.
3. Moore, N. “The Fitz-Patrick Lectures for 1905.” The Lancet, 1905:2, Part 2:1525.
4. Neumann HP. “Machina Machinarum: The clock as a concept and metaphor between 1450 and 1750.” Early Sci Med. 2010;15(1-2):122-91.
5. Noguera Palau JJ. “Nicolaus Cusanus, Jan van Eyck and concave lenses.” Arch Soc Esp Oftalmol. 2000;75(9):649-50. 6. Grüsser OJ, Hagner M. “On the history of deformation phosphenes and the idea of internal light generated in the eye for the purpose of vision.” Doc Ophthalmol. 1990;74(1-2):57-85.