L U N 



L U N 



toifes, it would be lefa expenfive, and its ditch and the coTcrt- 

 \Tay before it would be better defended by the lunettes. 

 Eleni. of Fortif. p. 36. 



LuNETTK, in the Manege, is a half horfe-flioe, or fueh a 

 (hoe as wants the fpunge, i. e. that part of the branch which 

 runs towards the quarters of the foot. 



liUNETTEisalfo the name of two fmall pieces of felt, made 

 round and hollow, to clap upon the eyes 'of a vicious horle 

 that is apt to bite, and ftrike with his fore feet, or that will 

 not fuller his rider to mount him. 



LUNE'VILLE, in Geography, a town of France, and 

 principal place of a dillrift, in the department of the 

 Meurthe, lituated between tlit Vefouze and the Meurthe, 

 in a marfhy plain, which has been drained. An academy was 

 inftituted here by king Staniilauf, and furniflied with a good 

 library. The place contains 9797, and the two cantons 

 2 2,334 inhabitants, on a territory of 345 kiliometrcs, in 37 

 communes; ij miles E.S.E. of Nancy. N. lat. 48 36'. 

 E. long. 6° 34'. 



LUNGKORCKE, a town of PrulTia, in the palatinate 

 of Culnj ; 10 miles N. of Stralhurg. 



LUNGOBARDI, in Ancient Geography. See Lom- 

 bards. 



LUNGON, in Geography, a fmall ifland on the W. fide 

 of the gulf of Bothnia. N. lat. 62 ' 40'. E. long. 17^ 

 48'. 



LUNGPOUR, a town of the country of Cachar ; 15 

 miles E. of Cofpour. 



LUNGRO, a town of Naples, in Calabria Citra, chiefly 

 inhabited by Greeks; 10 miles S.S.W. of Caffano. 



LUNGRY, a town of Bengal ; 36 miles S. of Calcutta. 

 N. lat. 21^58'. E.long. 87° 35'. 



LUNGS, \\\ Anatomy and Pliyfwlogy, are org-ans of the 

 body, (ituated in the cheft, through wliich the blood paffes 

 on its courfe from the right to the left fide of the heart, and 

 in which it is changed from the venous to the arterial ftate, 

 by means of expofure to the atmofpherical air received into 

 thefe organs in refpiration. 



The two lungs, (right and left,) are entirely alike in 

 their compofition'"; their fize is confiderable, and they con- 

 fift of feveral different tilTccs, which render their flrufture 

 complicated. Thefe tiffues are almoft all vafcular, which 

 gives to the lungs their charadlcriftic fpongy and foft nature. 

 They poffefs, befides the properties arifing from their orga- 

 nization, only the infenfible organic contradtility, or tonic 

 power. Perhaps the mufcular (ibres of the air-velTels may 

 conllitute an exception to this obfervation. In confequence 

 of their vital properties being limited to thi.s tonic power, 

 they are not capable of any motion in themielves ; and they 

 therefore remain motionlcfs, unlefs foine exterior agency puts 

 them in motion ; yet, in their funftions as refpiratory or- 

 gans, they exhibit a continual movement, an alternation of 

 dilatation and contraftion, by which the air is firll received 

 into their interior, and then expelled after a certain interval. 

 If this be interrupted for a very (hort time, the blood is no 

 longer ch<inged, the circulation ceales, and death follows. 

 The lungs then require fomc auxiliary means for the execu- 

 tion of the funftions to which they are dellined ; thefe are 

 furnifhed by the confiderable organs of motion fiirrounding 

 them, which at the fame time compofe a fufliciently firm de- 

 fence to proteft them againft external injury. The ribs 

 with their cartilages, the llernum, and the dorfal verlebrse, 

 form the fohd part of the cavity containing the lungs ; the 

 diaphragm and intercolfal muftles the moveable parts : 

 the cavity itfelf refulting from their union, is named the 

 tbxirax. To the fides of this cavity we mull refer the pheno- 



mena of dilatation and contracElion of the lungs, which are 

 entirely pallive, and follow the inipulf* received from this 

 fource. Thus the thorax conftitutes an edential part of the 

 refpiratory apparatus. 



But the thorax contains alfo the central or^an of the cir- 

 culation (the heart), and the large blood-veflels conneflcd 

 with it ; thus the apparatus of this fundtion is brought near 

 to, and in a manner confounded at its origin with that of 

 refpiration. Yet they are diftinft, by the difpofition of the 

 common cavity which contains them. For the heart occupies 

 that part of the chell which is formed by the vertebral co- 

 luinn behind, by the fternum in front, and by the aponeu- 

 rotic centre of the diaphragm below ; parts which are either 

 immoveable, or capable only of a Imall degree of motion. 

 The lungs, on the contrary, occupy the mod moveable 

 part of the chell ; thofe formed by the ribs and intercollal 

 mufcles, and the mufcular parts of the diaphragm. 



The following account of the refpiratory apparatus will 

 include defcriptions, ill, of the chell, in which the lungs are 

 contained ; 2dly, of the motions which that part is capable 

 of ; 3dly, of the membranes lining the cavities ; 4thly, of 

 the lungs themfelves; and Jlhly, of their funclions. 



The chell or thorax is a conical cavity, flightly flattened 

 in front, occupying the upper part of the trunk, and confe- 

 quenrly having a much larger Ihare of the fl<eleton below 

 than above it. Yet, if we compare its pofition to that of 

 the mod important organs, we Ihall find tlie latter placed al- 

 moll equally near the vifcera contained in the thorax. The 

 parts fituated in the head, and thofe contained in the abdomen 

 differ very httle in their diilance from the heart ; while the 

 latter organ is placed at very unequal diftances from the 

 upper and lower extremities. Hence the heart is the centre 

 of the organs contained in the head and abdomen, while it 

 exerts a much lefs aftive influence on the lower than on the 

 upper limbs. 



The chell is fituated in front of the vertebral column ; 

 but the curvature of the ribs, which is very prominent be- 

 hind, caufes the cavity to pafs a little beyond the fpine in 

 that direftion, particularly towards the middle. The plane 

 of the front of tiie cheft is poilerior to that of the front of 

 the face ; commonly it is nearly on a level with that of the 

 abdomen ; but the numerous variations of the latter cavity 

 produce correfponding varieties in this refpedl. 



A falfe idea wou'd be formed of the chell by examining it 

 when covered with foft parts, and articulated to the upper 

 limbs. The numerous mufcles furrounding it above, the 

 flioulder, and particularly the clavicle, give to its upper part 

 an extent in the tranfverfe direftion, which does not exill in 

 the flieleton, where the chell reprefents a cone flattened in 

 front and behind, with the bafis downwards and the apex 

 upwards. The longitudinal axis of this cone is oblique from 

 above downwards, and behind forwards ; but all its fides do 

 not partake equally in this obliquity, which belongs only to 

 the anterior and lateral parts : the poilerior, formed by the 

 fpine, has no concern in it. Hence a vertical line, drawn 

 from the middle of the fpace, included between the vertebral 

 column and the enfiform cartilage, perpendicularly through 

 the cheft, would not pafs out at the centre of the fupenor 

 aperture, but would go in front of the clavicular extremity 

 of the llernum. The diameters, whether antero-polterior 

 or tranfverfe, of the cone reprefented by the cheft, are all 

 larger in proportion as they are nearer the balls. 



In its general capacity the cheft holds a middle place 

 between the head and the abdomen. Its depth, from above 

 downwards, is much lefs in the natural ftate, than it appears 

 in the Ikelcton. The diaphragm below forms a confiderable 



arch 



