286 DISEASES OF THE PLEURA. 



among others. There is no doubt that emphysema, a disease which 

 formerly must have been as common as it is now, but the existence of 

 which was entirely unknown and overlooked, post mortem, until the 

 days of Laennec, was generally supposed to be a dropsy of the chest, 

 and was described as such. 



In the present state of science we know that such symptoms as se- 

 vere dyspnoea, aggravated by every slight exertion, and which compels 

 the patient to sit upright in bed, suddenly starting in terror from sleep, 

 and cedematous swelling of the malleoli and eyelids, do not always 

 denote the existence of hydrothorax, as similar symptoms occur from 

 diseases of the lungs or heart, without dropsy of the pleura. But, as 

 we know that hydrothorax is a very common event in diseases which 

 give rise to these symptoms, and that the distress of the patient is 

 greatly aggravated by such a complication, it behooves us to make 

 repeated physical exploration of the chest, that we may be aware of 

 the fact of its appearance. 



Physical exploration of the chest likewise furnishes the only certain 

 means of recognizing the existence of the hydrothorax occurring in 

 Bright's disease, or in any other malady, accompanied by general dropsi- 

 cal cachexia, as the symptoms of dyspnoea, which attend its develop- 

 ment and progress, are equally attributable to other sources, particu- 

 larly to incipient oedema of the lungs. The physical signs of hydro- 

 thorax bear great similarity to those of pleuritic effusion, although the 

 resemblance is not complete. 



Inspection reveals a dilatation of the chest in the region of the 

 transudation, but the intercostal furrows are not obliterated, since the 

 intercostal muscles, not being paralyzed by collateral oedema, offer 

 resistance to the pressure of the liquid. The liver, which is often en- 

 larged by venous engorgement, is depressed when the effusion is large, 

 but the heart is hardly ever displaced, as the pressure upon the medi 

 astinum is usually tolerably equal upon each side. 



Palpation gives an enfeeblement or total arrest of the pectoral 

 fremitus wherever the effusion touches the thoracic wall, while above 

 the effusion its intensity is increased. 



The percussion-sound is dull over the effusion, above it it is hollow 

 and tympanitic. The dulness does not extend itself in the peculiar 

 manner which is almost pathognomonic of pleuritic exudation. When 

 the patient stands or sits upright, its upper limits are upon the same 

 level both before and behind. Moreover, the boundaries and shape 

 of the area of dulness change slowly when the patient alters his atti- 

 tude. Upon auscultation over the region of dulness, the respiratory 

 sound is weak, indistinct, or even absent. Between the scapulae and 

 the spine there is feeble bronchial respiration. 



