Bohn, Johannes

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Bohn, Johannes

(b. Leipzig, Germany, 20 July 1640; d. Leipzig. 19 December 1718)

physiology, medicine.

Bohn was the son of a wealthy merchant family. He studied medicine in Jena and Leipzig and about 1665 received the doctorate from the medical school of Leipzig. From 1663 to 1665 he traveled through Denmark, Holland, England, Switzerland, France, and possibly Italy. In 1668 he was named professor of anatomy and surgery at Leipzig; in 1690 he became municipal physician; and the following year he was appointed professor of practical medicine. Bohn was a critical, truth-loving man who was so careful of his scientific reputation that on his deathbed he arranged for the destruction of all his unpublished writings.

Bohn’s accomplishments are in three areas; anatomy and physiology, iatrochemistry, and forensic medicine. His twenty-six Exercitationes physiologicarum appeared at irregular intervals from 1668 on; these are doctoral dissertations, written by Bohn and disputed by various candidates for the doctorate. Most of the Exercitationes appeared in 1668; the rest appeared from time to time until about 1677. They were later repinted as a whole in a pirated edition. Only a few copies of the work are available. Bohn later reworked these dissertations into a completely new composition which appeared in 1680 as Circulus anatomicuss-physiologicus seu Oeconomia corporis animalis, and was dedicated to Malpighi.

The Exercitationes and the Circulus show Bohn to have been an expert on the then new anatomical and physiological discoveries. He cites contemporary authors almost exclusively and thereby proves himself one of the innovators in physiology who completely forsook the Galenic tradition. He describes and discusses all major functions of the body. He complements the knowledge gained from the literature with numerous firsthand experiments, for example, experiments on bile and the biliary tract, lymph ducts, heart contractions, pancreatic secretion, on the conjectured swelling of ligated nerves, and artificial perfusion of an excised kidney.

Bohn’s basic attitude was mechanistic in that he gave predominantly physical interpretations of vital processes. He especially esteemed Malpighi, Borelli, and Boyle. Bohn had an excellent knowledge of iatrochemistry as well, but he maintained a critical position against this doctrine. He condemned the ancient theory of qualities as unsuitable to the explanation of chemical processes. Wherever possible, he referred to Jan van Helmont’s theories of the fermentum and to those of Sylvius on the acidum and the alcali. In his opinion, the process of digestion cannot be explained without the theories of iatrochemistry; with the help of spiritus and sal volatile, a fermentative transformation of food into chyle takes place. But he opposed a general explanation of physiological findings and clinical observations exclusively by these theories, and especially in his De alcaliet acidi insufficientia (1675) he explicates this attitude.

Bohn contributed several significant works to forensic medicine. He is considered one of the founders of this discipline and one of the initiators of forensic autopsy.


I. Original. Works. Bohn’s works on forensic medicine are not mentioned here. Among his other works are Disputatio de sudore (Leipzig, 1661), his dissertation, sponsored by Johannes Michaelis; Exercitationum physiologicarum XXVI (Leipzig, 1668–1677); Circulus anatomicus-physiologicus, seu Oeconomia corporis animalis, hoc est cogitata functionum animalium, notissimarum formalitatem et causas concernantia (Leipzig, 1680, 1686), dedicated to Malpighi and consisting of thirty progymnasmata and eleven other dissertations; Observationes quaedem anatomica circa structuram vasorum biliarumet motuum bilis spectantes (Leipzig, 1682); Dissertationes chymico-physicae, chymiae finem, instrumenta et operationes frequentiones explicantes… (Lepizeig, 1685, 1696); and De duumviratu hypochondriacorum (Leipzig, 1689), a polemic against Sylvius.

II. Secondary Literature. There is no biography of Bohn, but further information on him and his work may be found in A. von Haller, Bibliotheca anatomica, I (1774 , pp. 497–499; M. Neuburger, “Deutsche, Experimental physiologen des 17. Jahrhunderts,” in Deutsche medizinische Wochenschrifi, 23 (1897), 483–486; and J. C. Rosenmüller, DE viris quibusdam in Academia Lipsiensi Anatomes peritia in clavuerunt, III (1816), 7–9.

Also see Allgemeine deutsche Biographie, III (Leipzig, 1876), 81–99, with an incomplete BIBLIOGRAPHY; A. Von Haller, Bibliotheca medicinae practicae, 4 vols., III (Basel, 1778) 87–88, with a list of forty-two dissertations; Biographie médicine, I (Paris, 1855), 539–540; Biographie universelle ancienne et moderne, IV (Paris, 1843), 553; and Biograhische Lexikon des hervorragenden Ärzte aller Zeiten and Länder, 2nd ed., I (Berlin-Vienna, 1929), 606–607.

K. Rothschuh