640 POISON IVY POITOU hardly any circumstances is it more important that the so-called expert should be really a competent chemist than in cases of suspected poisoning, and nowhere has an ignorant or careless man a better opportunity to mislead a jury and defeat the ends of justice. The nu- merous popular antidotes for snake bites are all alike useless, and thus far science has failed to replace them with any agent deserving the name of antidote. In case of a bite by a ven- omous serpent, the proper plan is to isolate the part bitten by a ligature, and then if it be a small member, as a finger end, to have it promptly removed, but in any case to take enough of stimulus to carry the weakened heart over the period of depression which belongs to the early stage of venom poison- ing. In very grave cases artificial respiration may help to prolong life. See ANTIDOTES, MEDICAL JURISPRUDENCE, and the articles on the various substances mentioned above. POISON IVY, or Poison Oak. See SUMACH. POISSON, Simeon Deals, a French mathema- tician, born at Pithiviers, June 21, 1781, died at Sceaux, near Paris, April 25, 1840. In 1798 he was admitted to the polytechnic school, subsisting upon an income which barely kept him from starving; and in 1800 he was ap- pointed an instructor there. He became pro- fessor in 1802, was attached in 1808 to the bureau of longitudes, of which he afterward became" president, was chosen professor of mechanics of the faculty of sciences in 1809, member of the institute in 1812, examiner at the polytechnic school in 1816, counsellor of the university in 1820, and a peer of France in 1837. He was principally distinguished for his researches in the theory of definite inte- grals, and his application of the higher mathe- matics to mechanics and molecular physics. He was the author of about 300 memoirs on scientific subjects. His most important work is liis Traite de mecunique (2 vols., Paris, 1811; 2ded., 1832). POITEVIJV, Angnste, a French sculptor, born at La Fere about 1819, died in 1873. He studied in Paris, and exhibited in 1846 his first important work, representing " The Devotion of Viala." His group of "Judith" appeared in 1849, and was followed by several remark- able busts. For the new Louvre he executed groups symbolical of the fine arts, and for the museum at Amiens two statues representing Greek art and the Renaissance. POITEVIN, Prosier, a French lexicographer, born about 1810. He studied in Paris, and became a teacher, and for a short time was professor of rhetoric at the college Rollin. In early life he wrote poetry and plays, but he is best known by his grammars and dictionaries. The most important of his numerous works are : Nouveau dictionnaire universel de la langue franpaise (2 vols. 4to, 1854-'60), Gram- maire generale et historique de la languefran- faise (2 vols. 8vo, 1856), and Cours pratique de litter ature f ran false (2 vols. 12mo, 1865). POITIERS, or Poictiers (anc. Lernonum or Li~ monum, afterward Pictav'i), a town of France, formerly capital of the province of Poitou, and now of the department of Vienne, 180 m. S. W. of Paris; pop. in 1872, 30,036. It is situ- ated on a rounded eminence on the left bank of the river Clain, at the mouth of the Boivre. The town is enclosed by old turreted walls, pierced by five gates, four of which open on bridges over the Clain. It is the seat of a bishop, and has a cathedral, five parish churches, a castle, an academy, a royal college, several schools and hospitals, a public library, theatre, and botanic garden. Coarse woollen cloths, blankets, hosiery, lace, &c., are manufactured. The ancient Lemonum was the chief city of the Celtic Pictones. The Visigoths under Alaric were decisively beaten near the town by Clovis in 507; and in October, 732, Abder- rahman and his Saracens were defeated a few miles N". E. of it by Charles Martel. By the marriage of Eleanor of Aquitaine to Henry Plantagenet, afterward king of England, Poi- tiers came into the hands of that prince, and was held by the English until Philip Augustus recovered it in 1204. On Sept. 19, 1356, a few miles from the city, was fought the famous battle of Poitiers, in which John the Good of France, with an army variously stated to be 50,000 and 80,000 strong, was defeated by Ed- ward the Black Prince at the head of 8,000 English and Gascon soldiers. The English were so posted that they could only be ap- proached through a narrow lane, bordered on both sides by very heavy hedges. In these were the English archers, and at the head of the lane were the men-at-arms. The cavalry or knights were held in reserve. The French made an impetuous attack, but the first vol- ley from the archers put them into a confu- sion from which they did not recover. Being charged by the men-at-arms, they were com- pletely routed, and King John was captured. Poitiers again reverted to France in 1372 by the voluntary surrender of the townsmen to Charles V., the rest of Poitou having previous- ly been conquered. While the English were in possession of the larger part of France, Charles VII. held his court and parliament at Poitiers for 14 years. Numerous councils were held in Poitiers in the middle ages. During the war of the league it was taken from the Huguenots by the Catholics, and Admiral Co- ligni made an unsuccessful attempt to retake it in 1569. POITIERS, Diana of. See DIANA. POITOU, an ancient province in the west of France, bounded N. by Brittany, Anjou, and Touraine, E. by Berry, Marche, and Limousin, S. by Angoumois, Saintonge, and Aunis, and W. by the bay of Biscay. It was divided into Upper Poitou (the eastern half) and Lower Poitou (the western), the capital of the whole being Poitiers. Previous to the conquest of Gaul by Caesar, it was inhabited by the Pictones or Pictavi ; it afterward formed a part of the
