Page:The New International Encyclopædia 1st ed. v. 16.djvu/111

* PLAGIATJLAX. 83 PLAGUE. Woodward says that the family does not seem to have become extinct until early Tertiary times, for two other genera, Xeo-plagiaulax and Ptilo- dus, are known from the lower Eocene of France and Xew Mexico respectively. PLA'GIOCLASE (from Gk. -irXayios. plagios, oblique + /cXdcris, Idasis, fracture, from xXat. klaii, to break). A name originally introduced by Breitliaupt and applied by him to the triclinic feldspars of the albite-anorthite series of min- erals contained in the feldspar group. See Feldspar. PLAGIOSTOMJ, plfij'i-os'tuml (Xeo-Lat. noni. pi., from Gk. irdyios, j)Uigios, oblique -|- ffrSfia, stoma, mouth I. A suborder of cartilagi- nous fi^hes. coextensive with the Selachii. See Elasmobr.xchii. PLAGUE (Lat. jihiga. plague, destruction, in- jiry. blow, from plniigcre, connected with Gk. 7rXi}ildy with Goth, flokaii, OHG. fliiohhon, Ger. fl lichen, to curse), Pestls; Pestis BrBOXiCA : Pestis Imguixalis ; Bubonic Pl.^gue : Black Death. An acute infectious disease caused by the presence of a specific miciT)be and character- ized by the enlargement and suppuration of lym- phatic glands. HisTOKY. Under Black Death is given the histoiy of plague to and including the pandemic of 1334 to 13.51, when China. India, Persia. Russia, Germany, Italy. France. England, and Xorway were devastated, and many millions of deaths resulted. Proust is authority for the statement that between the eleventh and fifteenth centuries at least thirty minor epidemics of the disease appeared in different parts of Europe. A grave and important e))idemic was traced from Syria to Marseilles in 1720, when 80.000 people fell victims to the plague in that city. Dur- ing the epidemic of 1770-71. which probably passed from Jassy through Kiev, SO.OOO persons lay dead of the scourge in Moscow alone. Early in the nineteenth century Constantinople became the seat of two severe epidemics, one in 1803, with 1.50.000 deaths, and the other in 1813, with 110.000 deaths. The Balkan peninsula was visited bv the dread disease on several occasions between 1814 and 1841 : Greece suffered in 1828, and the southern part of Italy in 1815. Russia, in the neighborhood of Astrakhan, was swept by an epidemic from 1877 to 1879. While Europe was passing through this history and finally emerged from the shadow of the plague in 1879, Africa and Asia were suffering terribly. Kitasato reports 21 epidemics between 1783 and 1844 in Egypt. Tripoli suffered in 1874. as did also Arabia. In the river valleys of the Tigris and Euphrates outbreaks of plague occurred in 1773, and several subsequehtlv and as latelv as 1876, from which date it raged until 1895. The plague in Persia has been intermittent and of frequent occurrence ; perhaps the epidemic of 1876-77 is most noteworthy, because it was the source of the Russian infection in 1877. In India the disease has been endemic for centuries, although reliable and accurate accounts date only from 1815. Its record since that date has been unbroken. Bombay has been a special sufferer since 1896. To trace or chronicle the course and outbreaks of the plague in China is very difficult. The greatest visitation of the scourge, in 1342 and the following years, has been described. (See Black Death.) There were out- breaks of the disease in 1850, ISUO, 1871 and 1872, and subsequently. The pandemic of 1894 continues. It has been learned since .Japan an- nexed Formosa that plague has existed in the latter country for a very long time. C.rSE. Plague is not caused by filth, over- crowding, diseased grain, or inundations. It is always caused by the presence of the plague bacillus, or Bacillus pestis. The microorganism was discovered independently by Kitasato and Yersin in 1894. It is a small oval rod, short and thick, with rounded ends that take stain more readily than the central portion, showing the 'pole staining.' The bacilli are found in pairs or singly, and, in cultures, arranged in chains. They do not form spores and are motile. They occur in enormous numbers in the smaller glands (buboes), in the spleen, and after death in tlie blood. The lower animals, especially rats, are infected in large numbers from the dust in pest-laden houses. The unsanitary conditions under which the affected individuals live give ample opportunity for the direct or indirect transmission of the disease from patient to patient. Flies and other insects carry It. (See Insects, Propagation of Diseases by.) Kita- sato considers that the bacillus may enter the body by the skin surface, through cracks or wounds, by the respiratory passages, or by the alimentary canal. SYiiPi;ojiATOLOGY. Two forms of the dread disease are described — pestis major and pestis minor. Pestis minor includes various patholog- ical conditions, all of favorable prognosis, pre- sumed to be caused by the plague infections. Slight fever, slight swelling of the glands, or local tenderness with trivial systemic involvement, con- stitute the attack. In other cases, prostration, headache, vertigo, and gastro-intestinal disturb- ances occur. Those cases occvirring in houses in which plague has been found, and during a ])lague epidemic, are considered to be related to the scourge; but no bacteriological examinations have verified the suspicions. Pestis major (the severe or ordinary plague) may be of one of the following five varieties: (1) Bubonic, (2) pneu- monic, (3) septicsemic, (4) pysemic, or (5) local inoculation. An average attack of ordinary bubonic plague presents the following course: The period of inoculation lasts from three to seven days. The period of invasion, or prodromal period, varies from 24 to 48 hours in length, and during it the patient suffers with chills, fever, weakness, lassitude, vertigo, headache, and vom- iting. Bubo development follows, with stagger- ing gait, tremulous speech, and great restlessness ; a temperature of 104° F. or higher; a full pulse, averaging 130 to the minute; a dry granular tongue covered with a yellow velvety fur. but with a red margin; an anxious and pallid face; constipation ; and the enlargement of glands in the neck, groins, or axillip. constituting the buboes. Following the appearance of the buboes occurs a fall in temperature and pulse rate, and this generally on the second or third day of the disease. After a remission of a little over two days, the fever ascends to 103° or 105° F., at which point it remains for seven days, during which time the bubo reaches its full development. After 10 days the temperature falls. Emacia- tion and exhaustion are extreme. The patient may now die of heart failure, in syncope; or of