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Show ~-- Boole Ill Book III. 927 ‘ ~ :1 3948+: a," LL" The vitreous Humor of the Eye may recede from its due tranfpareney, as The r n , well as the Crifialline, when it lofeth its Purity, as fouled by fame grofs m5 iii? CHAP. XV. Recrements 5 Whereupon the vifib-le fpecies cannot be conveyed through "mum" it with clearenefs, to make due Appulfes upon the Retina 3 {0 that the Sight 0f the Di/éafes oft/ye Aranea, and the Crifln/[ine and Vitreom is more or lefs darkned, as the vitreous Humor groweth more or lefs oPThC ace. undue fituation of the vitreous Humor, very much incommodes the Humor, and their Cnrer. Sight, when it is not direétly placed againf't the Pupil. Tue grorsmr. He Crifialline Humor of the Eye is every way encompaffed With a ‘m‘ Am" thin tranfparent Tunicle, called by the Latina, Aranea. ' This fine Coat is fullied with grofs Humors, ifTuing out of the capillary carotide Arteries inferred into its fubflance 5 this difaffeétion is known When the Sight grOWeth dimm, as if it were celebrated through a White Vail lying deep in the Eye, which being free from this Difeafe, when we fix our Sight upon anothers Eye, it maketh the Image ofa minute Face in it, which cannot be feen, when the Arzmea is rendred fomewhat Opace, by a thick C H A P. XVI. 0f the rDiflaaflut of the Optick M712", and the Retina, and their Caren Recrement. n: Rum" Sometimes the Amnm is broken by the ill accident ofa firoke, or fall, and ""h‘A"""' other times corroded by {harp l‘aliue Humors ', whereupon this thin Film being fpoiled, the Criflalline and warty Humor are made confufed, when the fine party-Wall of the Aranea is dif-joyned. The Criflalline Humor confined within the Amnea, hath little or no co- lour, being oFa tranfparent nature, and is beautified with akind of orbicular ing from a grofs Nervous Liquor, not received into the Origen of the $3,l§°§;,,,_ depr‘efled Figures its fituation is in the middle, if a line be drawn through the middle of the Pupil to the Origen of the optick Nerve 5 but in reference to the anterior and pofierior region of the Eye, its fear is not in the Center, Nerves, feared in the Cortex of the‘ Brain; whereupon the animal Spirits are intercepted in their pallage into the Retina; {0 that the Appulfes of viiible Objects cannot be difcerned. ‘ . butinclines fornewhat to the fore-part and Pupil of the Eye. rising/a The Crifialline Humor, as loling its native confiitution, is liable to dighiiii‘iiiiii. verfe Dileafes, amongl't which the Firft may be called mum", when the Incl-1'41"" Crifialline Liquor quitteth its innate difpofition, and groweth fomewhar Opace, in being turned Greyilh or Blewilh', whereupon it is not duely receptive ofthe vifibie Images of things. The cattle of this Difeafc is, when the Cril'talline Humoris fomewhar dry- ‘ e tau e ot 3 EM; He chief Difeafes afliiaing the Eye, by reafon of the Oprick Nerves, is called by the Latinér, Outta Serena, by the Greeks «ital-tram, when A Gurus:the Sight is abolilhed, without any manifefi difafl'eétion inlef‘ting the Eye, """ which is produced by many Caufes: The Firfl: may be an Obf'truétion flow- The run The Second Caufe of a' Gutta Serena may be derived from Compreflion7 Tthecond wherein fiagnated Blood, or grofs chymous Humors, or (PM in an Ape; "mm" fleme, may comprefs the Extremities of the Nervous Fibres, placed in the Cortex of the Brain; whence the current of the Animal Liquor, and Spirits are fl0pped in their progrefs through the Optic‘k Nerves, into the {carof Vilion. ‘ V. V > ed and condcufed in old age, which is incurable 3 this Difeafe may be dilcern- A Third Caufe of the Gram Serena may be fetched from the laceration magma of the carotide Arteries, inferted into the Cortex, which is overcharged ' Ed; by "19311 971(in of Wllitcnefs appeareth dcepin the Eye, through WhiCh with Blood, comprefling the beginning of the Nerves, {cated in the 21me the‘IObji‘éts Vare'reprel‘ented toithc Retina, as through a Cloud 01' Fmoak. cut parts of the Brain. A caule of" another Dileai'e, relating to the Criltalline Humor, may be 'the ill fittiation of it, \V‘hen the anterior Region, fomewhat telembling the Figure ofia large Lentil, is not feared direé‘tly oppofite to the Pupil, AFourth Caufe may proceed from the Convulfive motions of the Origen of the nervous Fibrils, hindring the influx of the animal Liquor and Spirits into the Retina, the fubjeet of Vifion. . but is too much elevated or depreffed 3 but if one Eye bath the Crilialline And the difaffefiion of the Nerves, is not only the cau'fe of a Gum: Se- Th: optick rend, but the animal Spirits too, which ought to be Serene, and not mixed maxim, Humor duly feared, and the Other unduly, all 0bje&s appear double; but if both the Eyes have one kind of ill fituation, they only dull the Sight: without any gemination of the Object. The ill placing of the Crilt;1lline Humor may proceed from fome violtnt motion of a flroke or fall, or from the Birth, by an ill Conformation of the art. If the Cril'talline Humor be divided by fome ill accident, the Objects 3‘" reprefented double, in fume fort refembling a Looking-Glade brokeniuto d1verfc parts, which give many Reflections of the fame Object, according to l the various pieces of Glafs. The , , With grofs and dark Vapours, which fpoil the clearnefs of the animal Li- "a"fc' Quor, and do defiroy, or at leafl: leflEn the Sight. ‘ Another Caufe of the Gum: Serene may be derived from the inordinate A Wm" motion of the animal Spirits, not being capable to be received into the Ori- 0‘36"" gens of the Nerves, feated in the Cortex of the Brain 3 whereby the Sight is $755};ng Eitherleflened or abolifhed, as it is very confpi‘cuous in vertiginotts difpol'i- 223315;);tHans of the Brain. "‘5' Sometimes a Gum; Serena hath happened upon the taking of a violent °mlF0ry or Purge, highly agitating the nervous Liquor, and Blood, areaEd with grofs Chyme ; whereupon the Origens of the Nerves are fometlmcs E rI eom'ptetled |