CHORDATA, krir-da'tet (Neo-Lat. nom. pl., from Lat. chorda, chord). The phylum of the animal kingdom that embraces all the verte brat ed animals— fishes, amphibians, reptiles, birds, and mammals, together with the Pro chorda, or aseidians, and the Adelochorda, or llernichorda (see BA LANOOLOSS us ) —1 at sed upon the fact that all these have as a common feature a 'structure termed the notochord, although in some of the lowest it is present only in the very t.oung eondition. The notochord represents, and in the higher forms is replaced by, the spinal column. "Another nearly universal feature is the perforation of the wall of the pharynx, ei ther iu the embryonic or larval condition only, or throughout life, by a system of clefts—the bronchial clefts; and a third is the almost uni versal presence at all stages, or only in the larva, of a cavity or system of cavities, the neurocalc, in the interior of the body, lying above the central nervous system." CHOREA, 1:6-ri'Al (Lat., from Gk. xopeta, chorcia, dance), or SAINT VITUS'S DANCE. A disease characterized by involuntary and irregu lar jerky movements of the muscles of the face, neck, chest. arms. hands, legs. feet. back. or abdomen. The movements occur when the per son is performing voluntary motions, or when at rest but awake: they generally cease during sleep. Most eases occur in neurotic children be tween the ages of five and fifteen. and are caused by gout, rheumatism, fright, injury, or worry.
The disease is a little over twice as frequent in boys as in girls. Often the attack begins by drop ping articles, grimacing, stumbling, or winking. It may last from six weeks to six months, and re lapses are frequent. The appetite is variable, and nutrition is impaired, with resulting awe mitt. In about 90 per cent. of the cases fibrinous deposits are found on the walls of the heart. The seat of the trouble is in the brain and spinal cord, but there is no mental change in the patient, except slight emotional excitabil ity. Chorea is rarely fatal in the United States. In England the mortality reaches 2 per cent. The treatment consists in rest from violent exer cise and all mental exertion, cold sponging, nourishing food. iron, and arsenic, and a few other drugs, electricity, and change of air. One variety of chorea is hereditary; this is attended with progressive mental deterioration, and ter minates in dementia. (See INSANITY.) It is to be observed that the name Saint Vitus's dance 'dance of Saint Veit) was applied originally in Germany to a different form of disease from that above referred to—one closely approaching in its characters the epidemic 'dancing mania.' which in Italy was called taramism (q.v.). Consult Church and Peterson. Nervous and Mental Dis eases (Philadelphia. 1901).