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 568 PLAICE PLANET pulse small, weak, and frequent ; petechias are frequently present. The duration of the dis- ease varies. In the commencement of severe epidemics cases have been related in which the patients have died within 24 hours ; in most instances, however, it continues from one to two weeks. In severe epidemics the majority of the patients die, and when recovery takes place convalescence is tedious. Morbid anato- my hitherto has added nothing to our knowl- edge of the disease ; the blood is found to be altered and fluid, but no appearances have been noted which can be deemed characteristic. Of the treament of plague little is known. Near- ly all that can be done is to make local appli- cations to carbuncles and buboes, support the patient's strength, and place him under as fa- vorable hygienic circumstances as possible. PLAICE. See FLOUNDER. PLAOFIELD, a city of Union co., New Jersey, on the Central New Jersey railroad, 24 m. "W". 8. W. of New York; pop. in 1860, 3,224; in 1870,5,095. It is beautifully laid out. Many of the residents are engaged in business in New York, and very little manufacturing is carried on. A large amount is annually expended for the support of the public school, which ranks among the first in the state. There are two national banks, a savings institution, two week- ly newspapers, and nine churches. PL AM, Giovanni Antonio Amadeo de, baron, an Italian astronomer, born in Voghera, Pied- mont, Nov. 8, 1781, died in Turin, Jan. 20, 1864. He studied at the polytechnic school in Paris, and was professor of mathematics in the school of artillery at Alessandria from 1803 to 1811, when, at the instance of his uncle La- grange, he was appointed professor of astron- omy at the university of Turin, and in 1813 he became director of the new observatory in that city. He was made baron, senator, president of the academy of sciences, and associate mem- ber of the French academy, and Oriani be- queathed him 50,000 francs. In 1810 appeared his treatise Sulla teoria delV attrazione degli sferoidi ellittici. The most celebrated of his numerous subsequent works, published partly in Italian and partly in French, is Theorie du mouvement de la, lune (3 vols., Turin, 1832). PLANARIANS, a family of worms, or anne- lids, belonging to the order of turlellaria, which includes also the nemertians. Almost all the order are aquatic, and none are para- sitic; they have neither sucking disks nor booklets, but always vibrating cilia on the in- teguments. The planarians are soft-bodied, jelly-like, elliptical creatures, found in fresh water and on the seashore; the skin is fur- nished with numerous cilia, and with cells resembling lasso cells; the intestine, whether simple or branched, never has an anal open- ing ; the water vascular system communicates with the exterior; the nervous system con- sists of two ganglia, in front of the mouth, united by a cord ; there are rudimentary eyes, varying in number from two to sixteen. They Planarian, showing the branched intestine. are generally called flat worms, to distinguish them from the more elongated nemertians. The experiments of Dug6s show a remarkable power of repairing injuries, and that by par- tial division individuals with double heads and tails may be produced. They propagate by eggs deposited and fertilized in the water, by internal buds, or by transverse fission ; the young may develop directly into animals re- sembling the parents, or assume a jointed, bristly annelid structure, as shown by A. Agassiz, which is gradually lost ; or the larva may be totally unlike the parent, a worm- like animal separating from a part of the body wall, and the greater portion of the larva body perishing. The last case is similar to what oc- curs in some star fishes. Nearly allied forms develop themselves in one or the other of these ways, in the most capricious manner. PLANCHE, James Robinson, an English author, born in London, Feb. 27, 1796. In 1818 he produced successfully at Drury Lane theatre a burlesque entitled "Amoroso, King of Little Britain." In 1826 he travelled on the con- tinent, publishing on his return "Lays and Legends of the Rhine " and in 1827 " Descent of the Danube." In 1828 he produced at Drury Lane his 55th and perhaps his best dra- matic work, " Charles XII." He has produced more than 200 pieces for the stage, some of them being translated from the French. In 1830 he was elected a member of the society of antiquaries. In March, 1854, he was ap- pointed rouge croix pursuivant of arms, and in 1866 Somerset herald, which office he still holds (1875). He has also published " History of British Costume " (1834) ; " Eegal Records " (1838) ; " The Pursuivant of Arms, or Herald- ry founded upon Truth" (1852); "King Nut- Cracker, a Fairy Tale " (1853) ; " Popular Fairy Tales Illustrated" (1857); "A Corner of Kent, the Parish of Ash-next-Sandwich " (1864); " Recollections and Reflections : a Professional Autobiography" (1872); "William with the Ring: a Romance in Rhyme" (1872); "The Conqueror and His Companions " (2 vols., 1874). PLANCHE, Jean Baptist* Gnstove, a French critic, born in Paris, Feb. 16, 1808, died there, Sept. 18, 1857. He was educated at the Bourbon college, and in 1831 became a contributor to the Revue des Deux Mondes, and assisted Bal- zac in editing the short-lived Chronique de Paris. His slovenly habits caused him to be styled the " Diogenes of literature." He went to Italy about 1841, devoted five years to study- ing Italian art, and after his return published essays on the Italian masters. PLANER TREE. See ELM. PLANET (Gr. TrAavdo//^, to wander ; aorfip TrhavJjTw, a wandering star), a name formerly used to distinguish the seven celestial bodies which seem to move from the seemingly fixed