.. v . :: 



PARAl'KT. 



M 



ArorLUrl, ~~i after UM patient has recovered from 

 * UMsnsiUlity or general psralyw. by which the Mmire 

 followed. Mar* rarely it sppran in ru from congestion 

 of tie brain. and U not preceded by any fit, but 

 by deyeoi from (light to perfect UMS of nerroui 



The voTMtW* of iralyU. in which angle and small portion* of the 

 body are ilfcoUd, do not in general continue permanently limited to 

 Ut put first attacked, but are often precursor* of the more general 

 jMrinns already described. The most important forms, and those in 

 which the paralysis too* frequently ramaim for a long time local, are 

 thaw in which the eyelids or muscles of the eye, and thoee in which 



: . - - ' ' . ' 



In paralysis of the muscles of the eye, the moat commonly affected 

 are the elevator of the upper eyelid and the orbicular uiiucle of both 

 UM eyelid*. When the former low. its power, the eyelid drops, and 

 the rye is constantly more or lea* closed ; when the latter U affected, 

 the eye cannot be shut, and remain* permanently wide o]n. The 

 dropping of the upper eyelid (or plows) U dependent on a disease or 

 injury of the third pair of nerves, and u usually accompanied by a 

 paralysis of some of the muscles of the eyeball which are supplied by 

 the same nerve ; so that the position of the eye is altered, or it cannot 

 be freely moved. The permanent openness of the eye is the result of 

 iliitain of the seventh or facial nerve, or of iU branch supplying the 

 orbicular muscle ; sometimes this latter branch alone is implicated ; 

 but more frequently the whole trunk is affected, and there in coincident 

 paralytu of all the muscles of the face. As far as regards their influence 

 on vision, both en SB* are almost equally injurious ; the firat by placing 

 a veil coiuUntly over the front of the eye ; the second by destroying 

 the power by which particles of dust, &c., ore removed from the sur- 

 face of the ere, and thus leaving it exposed to the dangers of constant 

 irritation and inflammation. 



In paralysis of the face many different conditions are observed, 

 according to the nerve which has been diseased or injured. The 

 somlinii of the face depends entirely on the sensitive or larger portion 

 of the fifth pair of nerves [BIIAIN, in NAT. HIST. Div], the motion of 

 its muscles ou the seventh or facial nerves, and the motion of the 

 muscles of mastication ou the motor or small portion of the fifth pair. 

 Now if either of these three nerves or their sources in the brain be 

 separately injured, the paralysis will be limited to a loss of sensation, a 

 lost of the motion of the muscles of the face, or a loss of the motion of 

 those of the jaw. on the side affected. In the most frequent cases of 

 affection of the fifth nerve, both its sensitive and motor portion arc 

 injured, and then is both a loss of motion of the muscles of the jaw 

 and a loss of sensation of the whole of the skin of one side of the face. 



Lastly, a limb, or a part of a limb, or a single muscle or set of 

 muscles in any part of the body, may be paralysed. In some cases 

 such an affection is only a sign of disordered digestion, and thus they 

 occur chiefly in children ; in others it exists in what is called general 

 nervousness, as in hysterical women, who, with many other strange 

 disorders, sometimes lose the power of swallowing or speaking. Most 

 frequently, however, these forms of local paralysis depend on injury of 

 the nerves of the part, which are compressed by tumours or involved 

 in some diffused disease. 



An important class of local paralytic affections includes thoee in 

 which recent investigations have detected the sources of many cases of 

 congenital or acquired deformity, such as club-foot, curvature of the 

 spine, squinting, Ac. In these, one or more muscles of a limb or organ 

 being from birth or from childhood weak or powerless, its antagonist 

 muscles draw the part into an unnatural position, and hold it there 

 firmly and permanently fixed. One of the most important achieve- 

 ments of modern surgery is the cure of these affections by the division 

 of the contracted muscle or its tendons. [CONTRACTION.] 



These, however, are the only cases in which general rules of treat- 

 ment can be laid down. The varieties of causes from which paralysis 

 may arise, afford sufficient evidence that its treatment in different cases 

 must vary greatly. It cannot indeed be said to be a disease of itself, 

 since it is only a sign of some disorder of the nervous system, which is 

 often seated at a distance from the part whose motion or sensation is 

 lost. This disorder, also, U of no definite kind, but may be the result 

 of hemorrhage, or inflammation, or slow structural change of the 



UM motion in longitude and latitude separately, the method of varia- 

 tion of parameters was said to have been employed. l!ut the joara- 

 of the orbits 



nervous substance ; or it may be produced by the pressure of fractured 

 bones, or tumours, Ac. In each case, therefore, the cause of the para- 

 lysis must be treated before there can be any expectation of removing 

 its effects. 



PARA'MKTEU. This term was first used in reference to the conic 

 sections only, in which it was synonymous with latus rectum ; that is, 

 the perpendicular drawn to the axis through a focus, terminated both 

 ways by the curve, was the parameter of the curve. It was afterwords 

 used to denote any straight line or even numerical co-efficient, by the 

 value of which one individual curve of a species may be distinguished 

 from the rest. Thus the curve whose equation is y=ajc + tu? has two 

 parameters, a and b. This last phraseology was never in very general 

 use, and is now preserved only in questions in which what is colled 

 the variation of parameters is to be employed. Thus when in tin- 

 planetary theory the motion of a planet is ascertained by determination 

 of the variation of tho instantaneous ellipse [GRAVITATION ; On HIT], 

 and of the motion in that ellipse, in contradistinction to determining 



ore now generally called their rlcmtnit ; and the 

 first term is little used in astronomy, though it occurs frequently 

 enough in works ou the differential calculus to require notice in a 



..:,. .:':. 



1'AUAMK: ACID. This name has been given to a white crystalline 

 precipitate obtained by dissolving poramide iu ammonia and then 

 pouring the solution into hydrochloric acid. Its composition and even 

 lU existence ore somewhat doubtful. 



I'ARAMIDE vC.HNO.), JUcllimult, is formed when meUitote of 

 ammonia is heated in a retort to about 320. It is accomi>onied by 

 another body called eutliruic acid. I'aramide is a solid yellow sub- 

 stance, which when long boiled with water is changed into a bhuellitato 

 of ammonia. 



PARAMORPHIA, ftammoruhlne. [Oriuii, ALKALOIDS OF.! 



PARAMOUNT. [TITLI:.] 



I'AKAMUCIC ACID. [Mucic ACID.] 



1'AltANAI'HTHAI.IX. (XAI-HTHALIC Gitour.] 



I'AltAI'KT (from tho Italian -jiurapetio, compounded of the Greek 

 piv[Mitiou o/)a, " against," and petto, "breast;" in German, briut- 

 vxkr), a low or breast-high wall or fence, to serve as a protection on 

 bridges, terraces, platform roofs, tic. In Italian architecture, parapets 

 ore generally balustrades. In Gothic architecture, the parapet is a 

 continuation of the wall carried up above the edge of the roof, and 

 finished by a coping ; unless inachicolated, in which case it projects 

 and overhangs the walls below. [MACHICOLATION.] In the Romanesque 

 buildings of Italy there is seldom any parapet, the eaves of the roof 

 finishing the elevation. The same is frequently the cose iu the 

 Norman style, or else the parapet is quite plain ; whereas in Pointed 

 Gothic it is commonly embattled, even in ecclesiastical buildings, ond 

 both the battlements and the crenelles or spaces bn .. n ih. m have 

 usually moulded copings. In the Third Pointed or Perjiendicuhir 

 style, parapets and battlements ore either pierced or enriched with 

 panels. East Kisham manor-house is a fine specimen of such d. ccniti. .n 

 in domestic architecture. (Pugin's 'Goth. Examples,' vol. i.) The 

 perforated or open-work parapets of quatrefoil ornaments and other 

 carved patterns often form a very rich feature in ecclesiastical and 

 collegiate buildings of Third Pointed date. At a later period instances 

 ' occur of open-work for such purpose, forming the letters of some 

 motto, date, or inscription. In Elizabethan buildings open-work para- 

 pets, forming various fantastical devfces, are common. 



PARAPET, in Fortification, is generally an embankment of earth 

 which is formed either on the natural ground or on the upper surface 

 of the rampart of a fortress or outwork. In the latter case the parapet 

 rests on that part of the rampart which is nearest to the exterior of 

 i lie work, tho terreplein, or nearly level part on the interior side, being 

 occupied by the artillery or left free for the movements of the 

 defenders. Parapets of brick or stone are sometimes constructed I '>: 

 works which are masked by others in their front, or on heights, or ou 

 the sea-coasts ; but in other circumstances they would be improper, 

 because the splinters detached from such materials by the n 

 shot are dangerous to the defenders, whereas the shot sinks into earth 

 without doing further mischief. 



The height of a parapet above the ground, or above the terreplein of 

 a rampart which it surmounts, is about 7J feet, in order that it may 

 effectually cover the defenders behind it. In its mass ore cut ,tho 

 embrasures through which the guns are fired ; and a banquette, or 

 step, about 3 feet high and 4 feet broad is formed, usually of earth, at 

 its foot, on the interior side, in order to enable men, by standing on it, 

 to fire over the upper surface. The form of a transverse section of a 

 rampart, surmounted by a parapet, is represented in Jig. 2, BASTION ; 

 the parapet with its banquette being that which occupies, 011 the right 

 bond side of the figure, rather less than the upper half of the space 

 between the dotted lines. 



The exterior face of a parapet of earth is generally formed in a piano 

 making an angle of 45 degrees with the horizon, in order that the earth 

 may stand unsupported ; the superior surface, which varies in breadth 

 from 3 feet to 25 feet according to the nature of the shot which it is 

 intended to resist (from musket bullets to the balls discharged from 

 the heaviest ordnance), has its exterior crest or edge lower than the 

 other by about one-sixth of the breadth of that surface. It is recom- 

 mended that the depression of the slope should not bear a greater 

 proportion to the breadth, lest the upper part of the parapet should 

 by its ocutenesa be weakened ; but the general rule is that the pl.uu- 

 of the superior slope should, if produced, meet the counterscarp line of 

 the ditch in front, in order that the enemy, at the time of an assault, 

 and when detained by the obstacles there, may bo completely exposed 

 to the fire of musketry from the parapet. The interior face of the 

 parapet is frequently formed in a plane passing through the crest, and, 

 at the terreplein of the banquette, or at the foot of the parapet it 

 is no banquette, deviating from a vertical plane passing through tho 

 name crest about one-third of the height of the slope. By this inclina- 

 tion the earth, when reveled with fascines or sods, and even without 

 any revetment, will support itself for a time, while a man, by 

 leaning a little forward, in enabled without inconvenience to tire over 

 the parapet. 



Occasionally parapets of field-work* have been formed with the earth 



