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cerebellum

(Encyclopedia)cerebellum sĕrˌəbĕlˈəm [key], portion of the brain that coordinates movements of voluntary (skeletal) muscles. It contains about half of the brain's neurons, but these particular nerve cells are...

Zaleucus

(Encyclopedia)Zaleucus zəlo͞oˈkəs [key], fl. c.650 b.c., Greek lawgiver of Locris, in Italy. According to tradition, his was the earliest codification of Greek law. References to Zaleucus' code, which was widel...

stereoscope

(Encyclopedia)stereoscope stĕrˈēəskōpˌ [key], optical instrument that presents to a viewer two slightly differing pictures, one to each eye, to give the effect of depth. In normal vision the two eyes, being a...

farsightedness

(Encyclopedia)farsightedness or hyperopia, condition in which far objects can be seen easily but there is difficulty in near vision. It is caused by a defect of refraction in which the image is focused behind the r...

Zernike, Frits

(Encyclopedia)Zernike, Frits, 1888–1966, Dutch physicist, Ph.D. Univ. of Amsterdam, 1915. He was on the faculty at the Univ. of Groningen from 1915 until his retirement in 1958. Zernike received the 1953 Nobel Pr...

night blindness

(Encyclopedia)night blindness, inability to see normally in subdued light. It is usually a result of vitamin A deficiency. The rod cells, one of two light-sensitive areas of the retina of the eye, are impaired in t...

Purkinje, Johannes Evangelista

(Encyclopedia)Purkinje, Johannes Evangelista yōhänˈəs āˌväng-gālĭsˈtä po͝orˈkĭnyā [key], 1787–1869, Czech physiologist. While professor (1823–50) at the Univ. of Breslau he pioneered in establish...

pilocarpine

(Encyclopedia)pilocarpine pīlōkärˈpēn [key], naturally occurring alkaloid obtained from plants of the genus Pilocarpus (family Rutaceae). By mimicking the effects of acetylcholine, pilocarpine acts as a stimul...

Wald, George

(Encyclopedia)Wald, George, 1906–97, American biochemist, b. New York City, Ph.D. Columbia, 1932. He spent most of his career on the faculty at Harvard. In 1967 Wald, Haldan K. Hartline, and Ragnar Granit receive...

silvereye

(Encyclopedia)silvereye: see white-eye.