DIOSCOKEACE^. 269 riPHTHERIA. twining lierbs and shrubs, with large tubers or rhizomes, of wliieh the genus Dioseorea (see Yam) is the type. Some species bear aerial tubers in the axils of the leaves, as the air- potato, one of the species of yams. There are about nine genera and 200 known species. The Bowers are small, regular, and usually dioecious. The fruit is a capsule or a berry. The most important plants of the order are the ditlerent >|)i'cies of Dio.scorea , or yam. a number of which owur in the United States. Black bryony {Tnmiis communis) is a rcjiresentative species in the European flora. Tcstudinaria elephantipes, a South African species, sometimes called elephant's- foot, and Hottentot's-brcad (q.v.), has a large, fleshy rhizome, with a rough cracked bark, which is used as food by the Hottentots in times of scarcity. The chief genera are Dioseo- rea, Tamus, and Tcstudinaria. DI'OSCOR'IDES (Lat., from Gk. AiocrKop St/j , DioskoridC'i ) . Ped.xius. A Greek ])hysician. He was a native of Anazarbus, in Cilicia, and flourished in the first or second centui-y of the Christian era. He accompanied the Roman armies as physician through many countries, and collected a great store of infonnation on plants. In his great work, De Materia llcdica, he treats of all the medicinal substances then known, and their properties. Two spurious works, Alcxiphar- iiiaca and Tluriaca, assigned to him by Photius, are by a later Dioscorides of Alexandria. During fifteen centuries Dioscorides maintained undis- puted aiithority in botapy and in materia mediea, an authority which he still holds among the Turks and iloors. The best edition is by Spren- gel (Leipzig, 1829). The De J/a/en'a .l/erfica was translated into Latin at an early date, and later into all the vulgar tongues of western Europe. There is also an Arabic translation. DIOSTOLIS (Lat., from Gk. Ai6<riroic, city of Zeus). A name applied to several cities of antiquity. For Diospolis in Palestine, see Ltdda; and for Egyptian cities of the same name, see Theues. DIOS'PYEOS. See Ebony; Pebsimmon. DIOTIMA, di'6-ti'ma (Lat.. from Gk. Ato7(ua). The Mantinean priestess in Plato's fSymposium, who describes in figurative language the doctrine of Platonic love. DIP (AS. dyppan. dippan, to dip. Goth, daup- jan, OHG. toufen, Ger. iaufcn, to baptize, from AS. drop, Icel. djupr, Goth, diiips, OHG. tiof, Ger. lief. Engl, deep) . A term used by geologists to denote the inclination of rocks to a horizontal plane. Stratified and schistose rocks are seldom horizontal, and their dip may vary from a slight inclination to absolute verticality. The amount of dip (expressed in degrees) is measured by a clinometer (q.v.). When strata have been iip- raised into dome-shaped structures which have an outward slope in every direction from a cen tral point the dip is called 'quil-qua-versal.' DIPAVAIfSA, de'pi-viin'sa (Pali dipa, island -f ramxa. lineage). The title given to the oldest chronicle history of the island of Ceylon. It is written in the Pfiii langtia^'c and dates from the fourth century of our era. .
account is
given in this old record of P.uddha and the his- tory of Buddhism in Ceylon down to the year A.D. 302. Like the other Ceylonese chronicle, the Mahavan.sa (q.v.), to which it is akin, the Dipavansa is based on an older source. A record is preserved in the sclioliast on the Mahiivansa that King Dlifitusena (A.u. 459-477) caused the Dipa- vansa to be publicly read at an annual festival held in honor of Mahinda, the apostle who intro- duced Huddhisni into Ceylon. The text of the Dipavansa lias been edited and translated by Oldenbcrg, The Dlpavainsa ; An Ancient Bud- dhist Historical Record (London. 1870) ; Geiger, Dipaciihisa und Mahavainsa (Erlangen, 1901). DIPHTHETIIA, or DIPH'THERI'TIS (XeoLat., from Gk. SiiplHpa, diphlhrra, leather). An acute infectious an<l very dangerous disease, caused by the Klebs-lj<"itHer l)acillus. It is char- acterized by an inflamed throat in which a false membrane appears on the mucous membrane in patches, generally first on the tonsils, and then extending down to the larynx, up into the nasal passages, and into the mouth. It also appears on other mucous surfaces and upon any ulcer that may exist elsewhere. The false membrane is formed of lymph, which exudes upon the surface, together with mucus, pus, and the bacilli named. The mucous membrane is congested and swollen, and if the diphtheritic e.xudation be rubbed oft', bleeding occurs, and the spot is verj- tender. The patient is very weak and depressed, sutlers from fever, thirst, nervousness, insomnia, and loss of appetite. The throat is painful and the glands in the neighborhood swell and are tender, ilen- ingitis and Bright's disease frequently accom- pany diphtlipria, and paralysis is a frequent oc- currence during or a few weeks after the attack. The diagnosis of the disease is not alwajs easy, and suspicious cases of tonsilitis are quaran- tined, as are all eases of undoubted diphtheria, till cultures made with mucus from the neigh- borhood of the tonsils have been axamined micro- scopically for the bacilli of the disease. Besides separating the patient from the rest of the fam- ily by removing him to an upper room, from which carpets, upholstered furniture, and all cloth hangings have been removed, provision must be made for the nurse, so that slie may change her clothing and disinfect her face, hair, and hands, before passing through the house for her daily airing out of doors. Quinine, mercury, iron, chlorate of potash, and alcoholic stimulants are used by various physicians, though each is condenmed by some. 'The hypodermic injection of diphtheria antitoxin, introduced in 1894, gives by far the best results, as stated hereafter. HiSTOUY. It is believed that an epi<lcmic dis- ease which existed anterior to Hippocrates (c. 400-300 B.C.) was diphtheria. The malady is described by AretiBus of Cappadocia (c.lOO a.d.) under the names VJctis Hyriacum and Malum Egypticum. Perhaps the earliest modern treat- ise upon the disease was that by Hecktr. de- scriptive of the epidemic which prevailed in Hol- land in 1337. In 1.517 dijilithcria of malignant tvpe raged in Switzerland, along the Khine. and in the Xetherlands: in 1557 it was epidemic in France, Germany, Holland, and Spain. In 1(159 it had reached the New England States in this country. In 1765 a Scotch physician. Home, en- deavored to establish the fact that the pharyn- geal disease now called diphtheria was different from croup. In 1771 Dr. Samuel Bard, of New York, opposed Home, in a controversy, publish- ing very important and accurate observations re- garding the disease. The term 'putrid sore
