PURPLE-SHELL. 560 PURSUIVANT. menting women's gowns in drawn designs; and many per.sons made their living by this art. Con- sult works on eonchologj- and antiquities; espe- cially Lovell, Edible Mollusca of lireat Britain (•2d.*ed. London, 18S4). PURPLE WOOD, or Purple Heart. The plum-colored heart-wood of Copaifera pubiHora and Copaifera bracteata, of the natural order Leguminosie, natives of British Guiana, where it is generally called jVIariwayana. It is said that no other wood is so satisfactory for use in gun carriages and mortar beds, since it withstands the violent concussions remarkably well. Its great beauty and smooth grain should attract the at- tention of cabinet-makers. PUR'PURA ( Lat.. from Gk. Tvopiiipa, porphyra. purple-tish, purple dye). The term applied to a diseased condition in which a number of hemor- rhages occur under the skin, so as to produce blotches of a more or less purple color. These spots vary from one to four millimeters in diam- eter. Yhen small they are termed petechiae (q.v. ) ; when large they are known as eceh,-moses (q.v.). At first bright red in color, they be- come darker, and gradually fade to brownish stains. They do not fade on pressure. Purpura occurs as a secondary symptom in a large num- ber of diseases, among them being scurvy, rheu- matism, scarlatina, measles, smallpox, typhus fever, epidemic cerebro-spinal meningitis, the plague, leucocythjemia. Hodgkins' disease, cirrho- sis of the liver, and Bright's disease. It is dei)en- dent on an altered state of the blood. Purpura may follow the use of certain drugs, and snake poison produces a rapid extravasation of blood. As a distinct disease purpura occurs mainly in two forms, the simple and the hemorrhagic. These, however, may be regarded as essentially the same, but of dill'erent degrees of severity. In its mildest form purpura appears simply as an eruption of purplish spots on the legs alone or scattered over the body, and attended with little constitutional disturbance. Recovery generally takes place in from ten to twenty day^ In the hemorrhagic form the spots are larger and more numerous, and bleeding occurs from the mucous membranes. The nose, mouth, stomach and in- testines, kidneys, female generative organs, and the bronchi may be the sources of blood. Severe antemia ensues and great prostration is succeed- ed by death. There is often a rise in tempera- ture. This form is usually met with in young and delicate individuals, particularly girls. There are instances of purpura hemorrhagica of great malignancy, which prove fatal within twenty-four hours. The treatment of the mild form is simply rest in bed, tonic medicines, and simple food. In the severe eases efforts are made to stop the hemorrhage by the administration of drugs which have the power of contracting the blood vessels, notably ergot and suprarenal extract. Symp- tomatic purpura depends for its treatment on the nature of the disease to which it is secrindarv. R31 ^ W t PtTBPURA. A genus of ' y ^.rii' gastropod mollusks, repre- sented by Purpura Inpillus. a common snail living be- tween tide-marks on rocky chores of both coasi;s of the Xorth Atlantic. It is carnivorous and is supposed to destroy young barnacles. Other species of Purpura inhabit the soutliern coasts. PURPURE. The name for purple, one of the tinctures in heraldry (q.v.). PURPURIN (from Lat. purpura, purple) and Anthr.^^pl'Rplrix. Two isomeric organic coloring substances similar to alizarin and ob- tained along with it from madder root. They are formed also in the artificial production of alizarin (q.v.). PURSCH, or PURSH, Frederick Tr.lgott (?-lS20). A German-American botanist. He was born in Grossenhain. Germany, and educated at Dresden. He emigrated to the United States in 1799, and occupied himself with botanical re- searches until 1811, when he went to England and there published his Flora Ariicricce tiepten- trionalis (2 vols.. 1814), the most valuable work on the subject that had yet appeared. The fol- lowing year he issued Hortus Orlovieiisis, and he died in Montreal while preparing a work upon the flora of Canada. PURSE-CRAB, or Robber-Crab. Xames for the great Ea^~t Indian cocoanut crab (q.v.). PURSLANE (OF. porcelaine, pourcclaine, from Lat. purcilaca. portulaca. purslane). For-. tulaca. A genus of plants of the natural order Portulacacea-, the best known species of Nhich is COMMON PURSLANE. PCRPCRA LAPILLCS. common purslane (Portulaca oleracea) , which grows in cultivated and waste grounds on the seashore in almost all warm parts of the world, and is cultivated as a pot-herb. It is a short- lived annual, with spreading and rather pro- cmnljent stems, and obovate tleshy leaves, which, like the young shoots, are used in salads. The young and tender shoots are pickled in France like gherkins. PURSUIVANT, pfir'swe-vnnt (OF., Fr. pour- .sHui/ii*, follower, from poursuivre, to follow, from ' Lat. prosequi, to follow, from pro, before -|- sequi, to follow: connected with Gk. iirarBai, hepesthai, ■ Skt. sac, to follow, and ultimately with Eng. see). The third and lowest order of heraldic offices. The office was instituted as a novitiate, or state ; of probation through which the offices of herald | and king-at-arms were ordinarily to be attained. ' There are four pursuivants belonging to the i English college of arms: Roufie Croi-r, the oldest, , so named from the cross of Saint George; Blue Mantle, instituted either by Edward III. or ■ Henry V., and named in allusion to the robes of the Order of the Garter, or perhaps to the color of the arms of France: Rouge Dragon, deriving his title from King Henry VII.'s dexter sup-
