Page:The New International Encyclopædia 1st ed. v. 04.djvu/382

* CATARACT. 326 CATAWBA. darkness. The catoptric test, now disused, was an infienious method of distinguishing incipient cataract from certain otlier deep all'ections of the eye. Wlien a liglited candle is liehl before the eye of a person wiiose back is to the window, tliree candles are seen in the liealthy eye. Two are erect — tlie large front one caused by the convex cornea, the smaller and fainter one be- hind by the convex front of the lens. The third, occasioned by the concave back of the lens, is in the middle; it is small, bright, and is upside down; when the candle is moved it goes in the (pposite direction, while the two erect images move with the candle. When the back of the lens becomes opaque, the inverted image is ob- scured or disappears, and when the front of the lens is affected only the great front image, caused by the cornea, remains. At the present time cataract is accurately detected by con- centrating light upon the eye and illuminating its interior by means of the ophthalmoscopic mirror, the eye being previously dilated by some mydriatic, such as atropine or homatropine. Xo difficulty then arises in determining at once the nature of the disease. Xo medical or other treatment has any in- fluence in arresting the progress of cataract, nor can it be cured except by surgical operation. A clever imposture used to be practiced by quacks. By applying belladoima to the eye — as the surgeon does ^vhen he wishes to dilate the pupil for an examination or operation — some little light was temporarily admitted through the less opaque edge of the lens. The patient, beginning to see somewhat better, after long and increasing dimness of vision, began to con- gratulate himself on a cure. The quack, of course, hastened to get his money without wait- ing for the further result, which was sure to be blank disappointment. Traumatic cataract results from a perforat- ing wound of the capsule of the lens. The en- tire lens becomes opaque, and a portion of it usually remains so; but at times, unless inflam- mation of other portions follows, the cloudiness entirely disappears. Congenital cataract is due to imperfect development or intra-uterinc in- flammation. Juvenile cataract may be heredi- tary, or its caiise unknown. In both congenital and juvenile cataract the lens is soft and white. They are treated by 'needling,' an operation in which a needle-like knife is employed to cut and break up the lens at several operations. The injured lens is then absorbed. Senile cataract, the most important form, usually occurs in per- sons over fifty, and generally involves both eyes. Its period of development may be a few months or many years. Begiiming in the foriu of gray streaks extending from the periphery toward the centre of the lens, or as spots in any por- tion, it may eventually render the entire lens opaque. As the fluid of the lens is then ab- sorbed, it becomes easily sejia rated from its capsule, and is known as ripe for operation. If neglected, other changes may take place, mak- ing the results of operation poorer, from opacity of the capsule, etc. The only method of reliev- ing senile cataract is extraction of the lens, with or w^ithout excision of a portion of the iris. The ?ornea is opened along a little less than half its circumference, the capsule of the lens is cut, and the lens is expelled by gentle pressure. Great care must be used in the dressing and later treatment to avoid accidents. After re- moval of the cataract, the natural lens being absent, its place must be supplied by strong glasses. CATARMAN, kit'tiir-miin'. A town of Samar, rhilijipines, situated 93 miles from Catbalogan. Population, 11,000. CATARRH (Fr. catarrhc, Lat. catarrhus, from (ik. Kani, lata, down -f- pt'iv, rheiii, to How). A disease of great frequency in temi>erate lati- tudes, especially in changeable, moist climates, in the winter season. It is characterized by an increase in the nuicus naturally Iknving from the mucous membrane, preceded by a congestion and a brief period of dryness. Popularly a ca- tiirrh is called a cold, from the erroneous idea that it is due to a lowering of the temperature. More often it follows being overheated or breathing foul air, cheeking of perspiration, or constipa- tion. Catarrh may affect the nasal passages (rhinitis), the throat (pharyngitis), the vocal cords and neighboring parts (laryngitis), the membrane covering the eyeball and lining the cjelids (conjunctivitis), the stomach (gastritis), the bowels (enteritis), the urinary bladder (cystitis), the bronchi (bronchitis), and other tracts lined by mucous membraiK". Kach of these forms of catarrli is treated under its own name. CATARRH, Epizootic. See Kpizooty. CATARRH, XA.S.VL. See Gi...xders. CATAS'TROPHISM (Fr. cataslrophisme, from cutaatruiilir, Lat. catastropha, t!k. Kara- arfMiilij kiilastrophS, overthrow, from Kara, kata, down + a-poipl/j strophe, a turning, from arpi(fciv, strephciii, to turn). The doctrine that the vast changes which the earth has undergone from the beginning to the present time were caused by the sudden action of powerful physical agencies. Tliis hypothesis was maintained by some of the earlier geologists to explain the |)hysical features and structure of the earth's crust ; the upheaval of mountains, an<l the elevations and depression of land-areas were considered to be catastrophic phenomena. Its advocates also claimed that the changes which have taken place in life forms caimot be explained fully by the theory of evolu- tion and natural .selection as taught by Darwin, Huxley, and others. The doctrine of catastro- phism has met with str<mg opposition from lead- ing scientists, and its application in geologj' is no longer recogni/X'd. One of the ablest oppo- nents was Sir Charles Lyell. who made use of the forces and ])rocesses working at the present time to explain the geological history of the earth (uniformitarianism) . Consult l-ycll, Friii- ciplcs of Geology (London, 1875). CATAtrXI, ka-touks'e. A naked cannibal tribe of uncertain stock, living on the middle Purus Kiver in western Brazil. They are said to be remarkably handsome and of light com- plexion. They cultivate manioc, make pottery, use the blowgun with jxiisoncd arrows, and pow- der the roasted seeds of Acacia n'wpp for use as a narcotic stinuilant. CATAWBA. An Eastern tribe of Siouan stock, formerly holding a large district on tho river of the same name in South and North Caro- lina. They were once the ruling triln' of South Carolina, numbering 1500 warriors, or perhaps