Plebs 3759 Plethora themselves; but after 287 B.C., by a law of Hortensius, such resolutions, though not laws, were equally binding on all Roman citizens, and, in fact, most important measures were thus carried. In modern times it is practically synonymous with a referendum to the body politic. This method was used at the close of the French Revolution to determine the status of various annexations, and after the Great War there were several plebiscites taken, notably in Schleswig-Holstein and Upper Silesia. Another notable plebiscite was in the Tacna-Arica question. The Saar plebiscite took place in January, 1935, under League of Nations sup- ervision. See SAAR. Plebs, or Plebeians, in ancient Rome, the common people. Intermarriage between ple- beians and patricians was forbidden until 445 B.C. Under Servius Tullius the whole body of citizens, patrician and plebeian was formed into the Comitia Curiata, or national assem- bly. This history of Rome from 509 to 300 B.C. is that of the equalization of the two orders. One after another the plebs broke down all patrician privileges, until patrician birth be- came a mere pride of lineage. After the equal- ization of the orders a plebeian nobility arose, based on the tenure of high public office. From 300 B.C. onwards this nobility counted for more at Rome than patrician birth. Pledge, in English and American law, per- sonal property delivered over as security for a debt. Almost any personal property may be pledged, subject, however, to a few exceptions, such as the pay of an officer, and further sub- ject to the requirement ol delivery, for with- out delivery of the article to the pledge there is no pledge at law. It differs in this from a chattel mortgage. In a pledge title remains with the pledger and never passes to the pledgee, who only acquires a right to sell the article under statutes and subject to statutory regulations. The holder of a pledge is bound to take reasonable care of it, and is liable for negligence, but a pledgee may make reasonable use of the article while it is in his possession. A pledger may redeem the pledge until a sale with notice has been had, and he may sell it, giving the vendee all his rights. Pleiades, a conspicuous star cluster in Tau- rus, which figures popularly as the Seven Stars, though only six are commonly visible, the dis- crepancy being accounted for by the world wide tradition of a 'lost Pleiad.' Keen eyes, however, can discern many more than six Plei- ades; Maestlin reckoned 14, Littrow 16. The brighter components are of helium type. Phot- ographs of the pleiades exhibit it as densely nebulous. Pleiades, in ancient Greek legend, the seven sisters of the Hyades. The story runs that in Boeotia the hunter Orion pursued them, and the gods to whom they prayed for deliverance turned them into doves and placed them among the stars. Pleiocene, See Pliocene. Pleistocene System (Gr., 'most recent'), a system which comprises the older accumula- tions belonging to the Quaternary or Post- Tertiary division. In North Europe, and cen- tral and southern mountain regions of that continent deposits consist for the most part oi glacial and fluvio-glacial detritus which be- token the former presence of a great ice-sheet The remains of northern and Arctic plants and animals are met with both in glaciated coun- tries, and in the caves and fluviatile deposits that occur in regions that never were covered with glacier ice. The relics of man himself also accompany the same flora and fauna. The Pleistocene period was distinguished by great climatic oscillations. During the Pleistocene period a depression occurred along the Atlan- tic coast, and the subsequent elevation gave rise to many lines of raised beaches, as in the terraces of the Hudson Valley and along Lake Champlain. The Pleistocene fauna of North America embraced Mastodon, a true elephant, species of horse, bison, beaver, peccary, bear, etc., and gigantic extinct forms of sloth, such as Megatherium, Mylodon, and Megalonyx. Plenipotentiary, a diplomatic representa- tive invested with full power to settle all the affairs connected with the special commission for which he is appointed, subject to the rati- fication of his government. Meetings of such plenipotentiaries are generally held in some neutral country, so that they may settle trea- ties and terms of peace without the interfer- ence of any particular power. Plesiosaurus, a large extinct marine rep- tile of predaceous habits, which inhabited the Mesozoic seas. Different species range from 10 to 40 ft. in length. They had a compara- tively small and lizard-like head, borne on a long and flexible neck. The body was relative- ly not of great size, apparently unprovided with bony armor, and carried two pairs of long, powerful paddles or flippers. The tail was stout, and about as long as the body. Plethora, a term used in medicine to ex- press a state of general full-bloodedness, non- pathological, and not to be confused with the pathological conditions of congestion and in- flammation.