Kries

Kries Johann (Johannes v. Kries, 1853-1929), outstanding German physiologist, professor of physiology in Freiburg from 1883; known especially for his works in the field of physiology of sensory organs and in particular vision. A student of Ludwig and Helmholtz, Kries was a brilliant representative of the physico-chemical direction in physiology. As early as 1882 he published two outstanding works: "Die Gesichtsempfindungen und ihre Analyse" (Leipzig, 1882) and "Studien zur Pulslehre" (Freiburg, 1892). The physiological institute in Freiburg, organized and directed by K., attracted numerous scientific workers from various countries, including Russia. The works of Kries and his students provided experimental substantiation for the theory of dual structure of the visual apparatus. According to this theory, the elements that perceive color are the cones, functioning as the 'light apparatus' (Hellapparat) of distant vision, while colorless brightness is perceived by the rods as the 'dark apparatus' (Dunkelapparat) of twilight vision. Part of these works was published in "Abhandlungen zur Physiologie der Gesichtsempfindungen" (the last issue under the title "Abh. z. Phys. der Sinne", H. 1-5, 1897-1925). Among the numerous works of K., besides those mentioned, should be noted: "Physiologie der Gesichtsempfindungen" (Hndb. d. Physiologie, herausgegeben v. W. Nagel, B. III, Braunschweig, 1904-05); "Lehre von den Gesichtswahrnehmungen" (Helmholtzs Handbuch d. physiol. Optik, 3. Auflage, Band III, Hamburg-Leipzig, 1910); "Allgemeine Sinnesphysiologie" (Leipzig, 1923).