278 DISEASES OF THE PLEURA. 



the respiratory movement causes them to rub together with a certain 

 degree of rapidity. They are usually perceptible both upon inspira- 

 tion and expiration, and give a distinct impression of scraping or of 

 scratching, calling to mind the creaking of new leather, and there are 

 often little jarring interruptions. It is most liable to be mistaken foi 

 a buzzing rhonchus, which is likewise often perceptible to the touch. 

 A friction-sound, however, is scarcely ever as loud as a rhonchus, and, 

 besides, is not altered by coughing; whereas a rhonchus almost 

 always ceases after a vigorous cough, or, at all events, undergoes a 

 change. It is also somewhat characteristic of a friction-sound, that it 

 is heard more distinctly when the stethoscope is pressed rather firmly 

 against the chest. This sound is rarely heard in the beginning of the 

 disease, as the fibrinous deposit is not rough enough at first, and the 

 patients, while they continue to suffer pain, breathe cautiously, so that 

 the pleural surfaces do not rub together with sufficient quickness. 

 The time at which it is audible most frequently is when the exu- 

 dation begins to be reabsorbed, when the faces of the pleura, which 

 previously were separated by the serum, now once more come into 

 contact. They also become audible after evacuation of the liquid by 

 tapping. 



When the exudation is not very large, faint vesicular breathing, 

 transmitted by the surrounding parts, can be heard over the whole 

 region of dulness. When the effusion is very profuse, and when not 

 only the air-cells but the bronchi are compressed by it, no respiratory 

 murmur whatever is heard over the dull region, or, at the utmost, the 

 sound is very faint and indistinct. It is only between the scapulae and 

 the spinal column, where the compressed lung lies close to the thoracic 

 wall, that we can hear a feeble bronchial respiration and a faint bron- 

 chophony, the latter sometimes having a bleating tone, known as 

 cegophony. In a few instances, where there is severe dyspnoea, in 

 spite of the compression of the lung, and although we are obliged to 

 suppose that the greater part of the bronchi are compressed and do 

 not contain air, loud bronchial breathing is heard over the whole chest, 

 even at points where there is a large mass of liquid between the ear 

 and the lung, that is to say, at the sides of the thorax. Over the un- 

 compressed lung, both upon the diseased and healthy sides, the respi- 

 ration is loud and puerile, unless it be the seat of collateral hyperaemia 

 and catarrh, when rhonchi and rdles are to be heard. 



Of course, the physical signs of pleuritis are greatly modified when- 

 ever old adhesions of the pleura prevent the exudation from collecting 

 in the most dependent part of the chest. It would lead us too far to 

 ietail ah 1 these modifications, and we shall merely state that incapsu- 

 lated effusion of very considerable magnitude may form between the 



