Czermak(čermak), Johann Nepomuk

(b. Prague, Czechoslovakia, 17 June 1828; d. Leipzig, Germany, 16 September 1873,

Physiology, histology, phonetics, laryngologoy.

Czermak is remembered mainly for his contribution to the scientific development of laryngoscopy and its reception as a method of clinical examination. His name is also associated with the slowing of the heart and subsequent loss of consciousness caused by pressure exerted on the neck. (Czermak interpreted this as an effect of the mechanical stimulation of the vagus nerve, but it recently has been shown to originate from the carotid baroreceptors.) Two microscopic features of the teeth are named for him: the Czermak spaces, which are irregular gaps in the dentin that appear in rows, and the Czermak lines, formed by the Czermak spaces, which are arranged in rows and follow the contour of the dentin.

Czermak’s father and grandfather were physicians in Prague, and his uncle was professor of advanced anatomy and physiology in Vienna. He studied in Prague, Vienna (1845), Breslau(1847), and Würzburg (1849–1850). Very early he gained the advantage of the advice and sponsorship of Purkinje (then professor of physiology in Breslau), who deeply influenced his scientific interests throughout his life. Indeed, many of Czermak’s research subjects were further developments of topics studied by Purkinje (the structure of the teeth, subjective visual phenomena, touch, vertigo, phonetics).

It was his interest in the movements of muscles in speech and the conditions for producing certain unusual sounds(e.g., the Arabic gutturals) that led Czermak to use the laryngeal mirror in his research. Various instruments had been used previously by Philipp Bozzini (1807), Cagniard de la Tour (1825), Balington (1829), Gerdy (1830), Beaumes (1838), Robert Liston (1840), and Warden (1844) without any wider recognition of their utility. In 1855 Manuel Garcia, a singing teacher, published observations of his own larynx and vocal cords made with a small dental mirror introduced into the throat and using sunlight reflected by another mirror. García was interested in movements connected with the production of the singing voice and did not anticipate the importance of laryngoscopy for medicine. Attempted again two years later by a Vienna neurologist, Ludwig Türck, laryngoscopy did not seem either practical or promising, but Czermak, interested in physiological phonetics, greatly improved the technique. In his lectures in several European countries he bought home to physicians its usefulness and importance, thus opening a new and important field of practical medicine. He was also the first (not Friedrich Voltolini, as is sometimes stated) to use the same means for dorsal rhinoscopy. In phonetics he showed that the voice generated in the larynx does not participate in the production of vowels, but that both the voice and the acoustic conditions of the “joined pipe” (i.e., throat, mouth, and nasal cavities) play an important role in consonants.

In the physiology of sensations Czermak made the first systematic investigation of the spatial localization of skin sensibility, that is, of the two–point threshold in relation to the size of the E. H. Weber sensory circles (1855), postulated a general sense for duration of different specific sensations (Zeitsinn), and laid down a program for the investigation of the time sense (1857). He also contributed greatly to physiological experimental techniques, and some of his devices were widely used. He propagated the teaching of physiology by demonstration and designed for the purpose a model institute called a “spectatorium,” which was built and opened in Leipzig nine months before his death.

Czermak worked in Prague, Graz, Krakow, Vienna, Budapest, Jena, and Leipzig. Unable to comply with the requirements arising from the natural aspirations of Czechs, Poles, and Hungarians to develop teaching in their own languages at their universities, Czermak had to move several times and worked for some time as an independent scientist. He was afflicted with diabetes in his last years and was apprehensive of an early death—his father, uncle, and other male relatives had died in their forties. Czermak died at the age of forty–five, before he could finish his major theoretical work, “Die Principien der mechanischen Naturauffassung.”

BIBLIOGRAPHY

I. Original Works. Czermak’s writings were collected as Gesammelte Schriften, 2 pts. in 3 vols. (Leipzig, 1879). Among his books is Der Kehlkopfspiegel and seine Verwertung in Physiologie and Medizin (Leipzig, 1860), trans. into French (Paris, 1860) and into English as On the Laryngoscope and Its Employment in Physiology and Medicine (London, 1861).

II. Secondary Literature. A biographical sketch by Czermak’s friend and teacher, the art critic. A. Springer, is in Gesammelte Schriften, II. His introduction and propagation of laryngoscopy and dorsal rhinoscopy are discussed in all histories of laryngology—see, e.g., F. S. Brodnitz, “One Hundred Years of Laryngoscopy: To the Memory of Garcia, Tuerck and Czermak,” in Transactions of the American Academy of Ophthalmology and Otolaryngology, 58 (1954), 663–669—but there is no comprehensive discussion of his scientific work. Short biographies are by Durig, in Wiener medizinische Wochenschrift (1928), 791–792; and Münchener medisinische Wochenschrift (1928), 1509–1510; and Schrutz, in Praktický lékař (1928), 527–531. His accomplishments in rhinoscopy are discussed by L. Englert in Zprávy lékař4 (1934), 108–114; and by P. Heymann and E. Kronenberg in Handbuch der Laryngologie and Rhinologie, I (Vienna, 1898), 1–2, 24–35.

Vladislav Kruta