Ray

(ra). I. A beam, pencil, or cone of light; a line of light or heat proceeding from a luminous point. One of the component elements of light or of the spectrum. 2. One of a number of lines diverging from a common center. In biology, the branch of an umbel; the marginal flowers of an inflorescence when their structure varies from those of the disc, e. g., ligulate flowers, or circle of enlarged tubular flowers in heads of Composite, outer flowers in cyme of wild hydrangea. Rs., Actinic, solar rays that produce chemic change. Rs., Bipolar, rays leading from one point of divergence to another, as in the diaster of a cell undergoing indirect division. Rs., Chemic. See Rs., Actinic. R., Extraordinary, the polarized ray that departs farthest from the ordinary law of refraction. Its vibrations are parallel to the vertical axis. R., Fin-, one of the radiating, bony spines forming the framework of the fins in fishes. R. -floret. Same as R. -flower. R. -flower, one of the marginal flowers of an inflorescence when distinct from those of the disc. R. -fungus. See Actinomyces . R., Medullary, one of the vertical partitions of parenchyma radiating from the pith to the bark in woody plants, and separating the bundles of fibro-vascular ti ue. R.-oil, the oil of the liver of the fish called ray or skate, Raja bat is, said to be an effective substitute for cod-liver oil. R., Ordinary, the polarized ray which follows most nearly the ordinary law of refraction. Its vibrations are perpendicular to the vertical axis. Ray's Mania. A form of general moral insanity. Diseases, Table of. See Raygat's Test. See Birth .