SLAVONIA 455 SLIDELL 7th century migrated toward the Baltic Sea, the Danube and the Balkan penin- sula. The Germans in the 10th century- forced out the Slavs from many regions, which then became German. The Bul- garians, a Turkish people who had in- vaded the Balkan peninsula, were ab- sorbed by the Slavic occupants of the territory. The Slavic states are described under their several headings. See Slav- onia, Ukraine, Jugo-Slavia, and Czecho- slovakia. Also Balkan Peninsula; Balkan Wars. SLAVONIA, or SCLAVONIA, for- merly a province of Austro-Hungary, forming, with Croatia, a kingdom united with that of Hungary, now a province of Jugo-Slavia (q. v.), bounded N. and E. by Hungary, W. by Croatia, and S. by Turkey; area, of Croatia and Slavonia, 16,423 square miles; pop. about 2,650,000. Principal towns, Eszek (the capital), Pe- terwardin, Carlovitz, Semlin, Mitrovitz, and Brod. SLEEP, that natural state or condi- tion of unconsciousness in animals which alternates with a period of activity. In this state the involuntary functions, such as those of nutrition, secretion, etc., go on as usual, but the voluntary powers are quiescent. SLEEPING SICKNESS, Sleeping Dropsy, Negro Lethargy. A term applied to several distinct diseases. The first is a tropical disease caused by a parasite, Trypanosome gambiense, carried by a tsetse fly Glossina palpalis. This discovery was made in 1903. It is now considered possible that rat fleas play a part in its dissemination, and mosquitoes and other species of fly have also been suspected. The cause of the symptoms appears to be an inflammation of the lymphatics pro- duced by the presence of the trypanosome. This inflammation finally injures the brain, spinal cord, and their membranes, and leads to the so-called cerebral stage of the disease, which gave it the name sleeping sickness. Probably within two or three weeks after the bite of an infected fly the victim develops a fever, often accompanied by an eruption. The fever is intermittent or remittent. There may be neuralgic pains and the lymphatic glands are enlarged. During this stage the disease may be cured. Later, some- times after weeks or months of fever, the victim gradually loses his brightness, has difficulty in walking, is dull and apathetic, and develops a sort of palsy. Epilepti- form fits may occur. Emaciation and muscular weakness gradually increase, the saliva dribbles from the mouth, the intelligence wanes, and coma appears with a subnormal temperature, nnd the Datient dies. This sleeping stage lasts from a few weeks to several months. The only drug that has proved of any value is arsenic. This has been adminis- tered in various forms. Another disease of the same name appears at intervals in the United States and Europe. Its tech- nical name is lethargic encephalitis, or inflammation of the brain. While there is a close relation in the symptoms to in- fantile paralysis, the two diseases prob- ably have no connection. No definite rem- edy has been discovered for this malady. The best known preparation is called atoxyl. SLEZAK, LEO, an Austrian singer, born at Mahrisch-Schonberg, in 1876. He early developed musical talent and when only 17 years of age made his first ap- pearance as "Lohengrin." He sang in Berlin in 1898 with great success, and for seven years succeeding was a member of the Vienna Opera. In 1908 he began studying with Jean de Reszke, and in the following year made a remarkable success at Covent Garden, London. This was fol- lowed by his engagement, lasting a num- ber of years, at the Metropolitan Opera House in New York. He was especially excellent in the Wagner operas and in many of the Italian operas. SLIDELL, JOHN, an American states- man; born in New York City, about 1793; was graduated at Columbia University in 1810; studied law, and in 1819 went to New Orleans, where he soon acquired a large practice. He was appointed United States district attorney for Louisiana in 1829; elected to Congress in 1843; made minister to Mexico in 1845; and was in the United States Senate in 1853-1861. In September, 1861, he was appointed a Confederate commissioner to France, and in November set out with his associate, James M. Mason, for Southampton. Both commissioners were seized on the English mail steamer "Trent" by Capt. Charles Wilkes of the United States steamer "San Jacinto," and brought to the United States. After imprisonment in Fort War- ren he was released on the demand of Great Britain, and sailed for England in January, 1862. From England he at once went to Paris, where in February, 1862, he paid his first visit to the French minister of Foreign Affairs. His mission, which had for its object the recognition of the Confederate States by France, was a failure, but he succeeded in negotiating a large loan and in securing the ship "Stonewall" for the Confederate govern- ment. After the war he settled in Lon- don, England, where he died July 29, 1871.
