Hering, Ewald

Abstract

German physiologist Karl Ewald Konstantin Hering (1834–1918) was not only one of the founders of modern visual science but also made significant contributions in many other areas. In 1868, Hering and Josef Breuer reported that sustained distention of the lungs of anesthetized animals decreased the frequency of inspiratory effort or caused transient apnea, a reflex phenomenon designated eponymically as the Hering–Breuer reflex. In 1868, Hering proposed the law of equal innervation, which attributed the conjugacy of eye movements to innate connections in which yoked eye muscles are innervated equally; Hering's Law challenged Hermann von Helmholtz's view that each eye is controlled independently and binocular vision is learned. In 1872, Hering similarly challenged the trichromatic color vision theory of Thomas Young and Hermann von Helmholtz, which held that the human eye perceives all colors in terms of three primary colors; instead, Hering proposed the opponent process theory, which stated that the visual system operates using a system of color opponency, such that responses to one color of an opponent channel are antagonistic to those to the other color.