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. 2017;11(2):53-113.

The Pulsilogium of Santorio: New Light on Technology and Measurement in Early Modern Medicine

Fabrizio Bigotti  1 , David Taylor  2
Affiliations

The Pulsilogium of Santorio: New Light on Technology and Measurement in Early Modern Medicine

Fabrizio Bigotti et al. Soc Politica. 2017.

Abstract

The emergence of modern science in the sixteenth and seventeenth centuries had in medicine an important field of development thanks especially to the work of Santorio Santori (1561-1636). Mostly known for his contribution to the study of metabolism, Santorio was a pioneer in the use of quantification and developed several types of instruments, among which was a device called pulsilogium that represents the first instrument of precision in the history of medicine. First mentioned in 1602 by a colleague of Santorio in Padua, the instrument possibly constituted a source of inspiration for Galileo and sparked an entire path of experiments in seventeenth-century Europe. Santorio presented his inventions in a series of rough engravings in his Commentaria in primam Fen primi libri Canonis Avicennae (Venice 1625) promising soon to publish another book called De instrumentis medicis: a task that, unfortunately, he was never able to fulfil. As a consequence, many descriptions related to Santorio's instruments are partial or too general to provide a proper understanding of their mechanism. In order to understand the exact application of Santorio's ideas to physiology, their reconstruction represents an essential task for any historian and philosopher of science. Relying on a new assessment of Santorio's works, newly discovered documentary proofs as well as on experimentation carried out at the University of Exeter, we present here for the first time the key principles that led to the historically accurate reconstruction of the pulsilogium A2. The results are possibly of some importance in the history of science, as, unlike all previous scholars, we can now prove that the pulsilogium represented a moment of transition and departure from the late Aristotelian physics towards Galileo's mechanics and that, despite the latter's discoveries, it continued to be used not to obtain an absolute measurement of the pulse rate, but to record its 'latitude'.

Keywords: Galen; Galileo Galilei; Mechanics; Medicine; Paolo Sarpi; Pendulum; Pulsilogium; Santorio Santori; University of Padua.

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Figures

Figure 1
Figure 1
Benedetti’s demonstration that the weight of body depends upon the distance from fulcrum. The direction of the weight is expressed by the perpendicular, so that it progressively decreases the more the weight CO comes closer to the centre of gravity laying on the line QBA as it is in the case of the perpendicular FM.
Figure 2
Figure 2
Apianus’ edition of Iordanus Nemorarium Liber de ponderibus (1533). Engraving from the frontispiece, showing the mechanism of the steelyard according to the Aristotelian principles of mechanics
Figure 3
Figure 3
Del Monte’s example of a balance whose centre of gravity lies at the bottom of the circle.
Figure 4
Figure 4
‘Statera medica’
Figure 5
Figure 5
Anemometer
Figure 6
Figure 6
Water current meter
Figure 7
Figure 7
Beeckman’s diagram explaining the isochronism of vibrating chords (1630).
Figure 8
Figure 8
An example of ‘Pendulum Scale’
Figure 9
Figure 9
Marci’s ‘Pulsilogium’ (1639)
Figure 10
Figure 10
Kircher’s Filochronometro (1665). Rather than being provided with a tapered/tuning peg on one side, as in Santorio’s and Marci’s design, Kircher’s instrument presents two weights that can be pulled up and down in order to match the increase or decrease of pulse frequency.
Figure 11
Figure 11
A1
Figure 12
Figure 12
A2
Figure 13
Figure 13
B1
Figure 14
Figure 14
B2
Figure 15
Figure 15
Figure 16
Figure 16
Replica 1 Pulsilogium with vertically angled beam, no scale and arbitrary dimensions.
Figure 17
Figure 17
Replica 2 Pulsilogium with horizontally angled beam, no scale and arbitrary dimensions.
Figure 18
Figure 18
Replica 3 Pulsilogium with vertically angled beam with fake scale and arbitrary dimensions.
Figure 19
Figure 19
Replica 4 Vergara-Caffarelli’s model for an alleged ‘Galileo’s pulsilogium’. Design of this pulsilogium does not correspond to any historical account.
Figure 20
Figure 20
a. Frontispice of Jan Marek Marci De proportione motuum (Prague: 1639) b. Detail from Marci’s frontispiece showing a portable version of the pulsilogium with the beam angled horizontally.
Figure 21
Figure 21
a-b. Pulsilogium A2 - Orientation of the beam
Figure 22
Figure 22
Santorio’s Pulsilogium A2 (November 2017)
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