YELANSK. KoTO-Cherkask (Map: Russia, F 5). It is en- gaged principally in fishing, farmin;;, gardening, and sheep-raising. Population, in 1897, 11,200. YELETZ, yel'ets. A town in the Government of Orel, Russia, 120 miles east-southeast of the town of Orel ( Map : Russia, E 4 ) . Lace-making is a widely spread household industry. Popula- tion, in 1807. 37.4.55. YELIZAVETGRAD, ye-lye'za-vet-grat'. A district town in the Government of Kherson, South Russia, situated on the Ingul about 740 miles south of Moscow (Map: Russia, D 5). It consists of a town proper and four suburbs, and is well built, with straight wide streets and avenues of trees. Yelizavetgrad is after Odessa the principal manufacturing town in the government. There are extensive flour mills, tobacco fac- tories, etc. There is a trade in grain and flour, cattle, sheep, wool, horses, crockery, timber, and leather goods. Population, in 1897, 61,800, in- cluding 1-2.300 Jews. YEIilZAVETPOL, ye-lye'za-vet-p61'y', or Elizaketi'ol. a government of Transcaucasia, Russia, bounded by Persia on the south; area, nearly 17,000 square miles (Map: Russia, G 6). It belongs partly to the region of the Little Cau- casus and is partly covered with steppes. It is watered chiefly by the Kur and its tributaries. The mountain slopes are thickly wooded and some of the valleys are fertile and well culti- vated. There are' rich mineral deposits, espe- cially of copper, which is mined on a consider- able" scale. Agriculture is the chief occupation and considerable quantities of wine are produced. The government is traversed by the Transcau- casian Railway. Population, in 1897, 871.000, of whom aliDUt 00 per cent, were ^lolKinimedans. YELIZAVETPOL, or ELIZABETPOL. A town of Russia, cajiital of the Government of the same name, situated on an affluent of the Kur, about 120 miles southeast of Tiflis (Map: Rus- sia, G 6). The older portion of the town is occupied mostly by Mohammedans and is ill built with narrow and crooked streets and low-roofed houses. The new portion is built on a nunlern scale and contains some fine buildings. Yelizavet- pol has a mosque dating from the seventeenth century, an ancient mausoleiim. and a fine liazaar. In the'neighborhoodof the city are found numer- ous ancient remains. The fortifications con- structed by the Turks are still in existence. The chief occupation of the inhabitants is agricul- ture. Popiilation, in 1897, 33,100, consisting chiefly of 'l';itars and .ruienians. YELLOW BASS. A fresh-water bass (Morone interrvpta) of the .southern Mississippi Valley, about 15 inches long, brassy yellow, willi about seven distinct longitudinal black lines, the continuity of which is broken toward the tail. See B.ss', and Phite of Bass. YELLOWBELLY. A common sunfish (Le- pomis (nirilus). See SuNFlsii ; and Plate of DaRTF.RS AXn Sl'NFISIl. YELLOWBILL. A sportsman's name for the jmerir:ui libick scoter. See Scoteu. YELLOWBIRD. .' y of many distinctively yellow liirds. In Die fnited States the 'common,' 'thistle.' or l)lack-wingcd yellowbird is the goldfinch (q.v.) ; the 'summer' yellowbird, or 'wild canary,' is a warbler (q.v.). ri6 YELLOW FEVEE. YELLOW FEVER, or 'Yellow Jack.' An acute specific disease, occurring within certain geographical limits and characterized by a fever of short duration, a yellow tint of the skin, gastro-intestinal disturbances, and heniorrliages into the skin and mucous membranes. It is due to the action of a specific virus, the preci.se na- ture of which is unknown. The disease was first recognized definitely in 1G47, in the West Indies. In 1091 it was very fatal in the Barbados, where it was called the 'new distemper.' From this date the disease has been endemic in the West Indies. It is also prevalent along the west coast of Africa at Senegal and Sierra Leone. At times the disease extends southward along both shores of South America, and northward to the south Atlantic and Gulf States. Occasionally it is brought to the large Atlantic seaports by ships sailing from countries where the fever prevails. Severe visitations occurred in the lower Missis- sippi Valley in the autumn of 1878, the deaths in New Orleans and Jlemphis alone exceeding 5000. Until the American occupation of Cuba in 1898 yellow fever was practically never ab- sent from that island. Experiments carried on in Cuba under the auspices of the medical department of the United States Army have proved that this disease, like malaria, is communicated from one individual to another by a species of mosquito (SIcfiomyia fasciat a), and by it alone. (See Insects. Prop- agation OF Disease by.) Since the recogni- tion of the true etiology' of yellow fever, and the institution of sanitary reforms in Cuba based on this knowledge, the disease has completely disappeared from that island. Its occurrence in hot and moist areas and at low levels coincides with the distribution of the mosquito. It is more fatal in the summer montlis, from May to August, and is stopped b.v the onset of frost. All ages and both sexes are equally alTected under like conditions of exposure, but negroes are less susceptible than whites. One attack confers im- munity against others. Attempts to discover the causative germ of yellow fever (if one exists) have been unre- mitting. Difl'erent observers have claimed to have found a bacillus which is constantly pres- ent, and the fact that a definite time (twelve days) elapses between infection of the mosquito and the development of its power to communicate the disease to man, points to a germ as the agent. Careful experiments and investigations, however, by the United States Army Commission in Cuba show that no bacterium or protozoan of any kind is present in the blood tissues or excreta of yel- low-fever ])atients; that their blood is capable, when injected into healthy persons, of communi- cating the disease; and that the serum of the blood, wlien sejiarated, is also infective. The conclusions are that the specific agent is in the serum, and th.at it is either ultra-microscopic or it is non-bacterial and probaldy a toxin. The period intervening between infection and the onset of the disease is as a rule tliree or four days, but may be from one to seven days. The attack may come on suddenly with severe chills or rigors or may be preceded by .symp- toms of languor, headaclie. and m:il;iria. The temperature rapidly rises and in two or three days may rc;u-li 105° F. or even higlier. The fever lasts from three to five days and is at-
