794 



DIAPHRAGM 



DIARRHCEA 



visceral cavity viz. posteriorly, a vertebral portion 

 arising from the lumbar vertebra; by two pointed pro- 

 cesses, or crura, of unequal length, ana from two 

 fibrous bands, or arched ligaments, on each side 

 of the bodies of the vertebra : laterally, a costal 

 portion arising from the cartilaginous and adjoining 

 osseous parts of the lower six ribs ; anteriorly, a 



sternal portion 

 arising from the 

 ensiform cartil- 

 age of the ster- 

 num, or breast- 

 bone. From 

 these various 

 points the mus- 

 cular fibres con- 

 verge to the cen- 

 tral, trefoil, or 

 cordiform ten- 

 don, which 

 forms the high- 

 est part of the 

 diapnragm, and 

 as its name in- 

 dicates, consists 

 of three lobes. 

 The diaphragm 

 presents three 

 large perfora- 

 tions or fora- 

 mina ; one, 

 quadrilateral, 

 The lower part of the Thorax, opened placed in the 

 to show the upper side of the Dia- highest part of 

 phragm from before : t j tendinous 



a, sixth dorsal vertebra ; 6, fourth lumbar centre for the 

 vertebra; e, ensiform cartilage; dd', lir . w ., rr | n i<wii 

 aorta ; e, oesophagus ; /, opening for upward passage 

 inferior vena cava. 1, 2, 3, trefoil ten- OI the interior 

 don ; 4, 5, central portions of diaphragm ; vena cava ; one. 

 6, right, and 7, left crus of diaphragm. oval in form 



surrounded by 



muscular fibres derived from the crura, for the 

 passage of the oesophagus and pneumogastric 

 nerves; the third, situated in front of the verte- 

 brae and bounded by tendinous fibres of the crura, 

 transmits the aorta, thoracic duct, and large azygos 

 vein 



The upper surface of the diaphragm is in relation 

 to the pleural membranes which inclose the lungs, 

 and the pericardium which incloses the heart. The 

 latter membrane is intimately connected with the 

 central tendon, which thus forms a fixed floor for 

 the support of the heart. The lower surface, deeply 

 concave in form, is lined by peritoneum, and has in 

 apposition with it the stomach and spleen on the 

 left side, the convex upper surface of the liver on 

 the right side, and the kidneys, supra-renal capsules, 

 and duodenum posteriorly. 



When the diaphragm contracts, the arched portion 

 becomes flatter, and the cavity of the chest being 

 thereby enlarged, air rushes in to fill the vacuum, 

 and expands the lungs during the act of inspiration. 

 It is thus an inspiratory muscle, and in ordinary 

 quiet breathing tne central tendon on which the 

 heart rests takes no share in this movement. Every 

 contraction of the diaphragm must diminish the 

 abdominal space and compress the abdominal 

 viscera, and hence it aids in the expulsion of the 

 faeces and urine. 



Spasmodic action of the diaphragm produces 

 hiccough and sobbing. Stoppage of the action 

 of the diaphragm, whether from great external 

 pressure or from paralysis, is very speedily fatal. 



DIAPHRAGM, a partition with a hole in it, 

 employed not only in landscape and portrait lenses 

 for photography, but also in telescopes, micro- 

 scopes, and other optical instruments, for the 

 purpose of cutting off the superfluous rays of light, 



and producing greater intensity or sharpness of the 

 image, as well as to correct aberration. 



Diarbekir, a town of Asiatic Turkey, capital 

 of a province of the same name, is situated on 

 the right bank of the Tigris, 390 miles NW. of 

 Bagdad. The town is surrounded by high strong 

 walls, and commanded by a citadel built on a 

 high basalt rock, against which the flat roofed 

 houses rise above each other in terraces. The 

 population has dwindled to 40,000, mostly Kurds 

 and Armenians. The city is the residence of a 

 pasha, and the seat of a Greek bishop, as also 

 usually of the Jacobite patriarch of Antioch. It 

 has 27 mosques and 12 churches, and numerous 

 bazaars, fountains, baths, and caravanserais, 

 although the last are now falling into decay. 

 Indeed, only in the centre of the town are any of 

 the buildings handsome ; elsewhere ruins meet one 

 at every step. Stagnant pools, weeds, and filth 

 combine to produce fevers. Diarbekir had formerly 

 extensive manufactures of silk and cotton goods, 

 and an active commerce with Aleppo and Bagdad ; 

 and it still has considerable trade in raw products. 

 The roads to the coast are equally bad and insecure, 

 and the traffic with Bagdad is mostly by raft. The 

 principal exports are wool, mohair, sheep and 

 goats, copper ore, butter, gall-nuts, goat and kid 

 skins, and furs ; the imports include cotton and 

 woollen goods, indigo, coifee, sugar, buffalo-hides, 

 petroleum, and soap. Diarbekir occupies the site 

 of the ancient Amida, which was fortified by the 

 Emperor Constantine. It was captured by the 

 Persians in 359, and retaken by Justinian ; but in 

 502 the Persians once more became masters, and 

 put 80,000 of the inhabitants to the sword. In 640 

 it fell into the hands of the Arabs of the Bekr tribe, 

 whose name became identified with the district ; 

 but the Turkish official title is still Kara Amid 

 ('Black Amid,' from the colour of its basaltic 

 walls). After many vicissitudes, the town passed 

 into the hands of Sultan Selim in 1515. 



Diarrhce'a (Gr. dia, 'through,' and rheo, 'I 

 flow') is the name applied to an increase in the dis- 

 charges from the bowels, which are usually unduly 

 liquid, sometimes overcharged with bile, and some- 

 times the contrary, and is, properly speaking, a 

 symptom rather than a disease. Thus it often 

 occurs in the course of diseases of the liver and 

 spleen, of some forms of heart-disease, of many 

 fevers and other acute diseases, and is a common 

 complication of the advanced stage of Consumption 

 (q.v. ). Frequently, however, it is the most pro- 

 minent, perhaps the only symptom of ill-health ; 

 and it may then take rank as a disease, or rather 

 as the generic name of a group of diseases. In this 

 aspect the subject will be discussed here. 



Diarrhoea is either simple, bilious, or choleraic ; 

 the last form has already been discussed (see 

 CHOLERA ). The ancients applied the name lientery 

 to a diarrhoea in which the dejections consisted of 

 matters not digested, or very partially so ; this 

 form is, however, very unusual, at all events in 

 Britain. Dysentery (q.v.) is also a form of 

 diarrhceal disease ; as is the form of Fever (q.v.) 

 called gastric, typhoid, or enteric fever. Simple 

 and bilious diarrhoea probably often differ only 

 in degree ; they are both distinguished from the 

 advanced stages of cholera and dysentery by the 

 presence of abundance of biliary colouring matter 

 in the stools, and by the absence of the distinctive 

 features of the other two diseases as described 

 elsewhere. Diarrhoea is almost always accompanied 

 at first by pain in the abdomen, sometimes severe 

 or even agonising in character. According to its 

 cause and treatment, it may pass off in a few hours, 

 or may persist for a few weeks or months ; or it 

 may even prove fatal. 



