18G DISEASES OF THE PARENCHYMA OF THE LUNG. 



ehi, but are only perceptible upon the surface of the chest as an India 

 tinct buzzing, as long as the healthy pulmonary substance lies between 

 the ear and the bronchi ; the healthy lung-substance being, as we know 

 a bad conductor of sound. If the parenchyma become condensed, and 

 its transmitting power thereby improved, the bronchi also becoming 

 better conductors of sound, from the thickening of surrounding parts, 

 the sound of the voice in the thorax is louder, constituting " broncho- 

 phony ; " sometimes a tolerably distinct articulate sound is heard, which 

 is called " pectoriloquy" If the sensory "herves of the ear perceive an 

 unpleasant jarring sensation from the thoracic wall, we have the " strong 

 bronchophony," which therefore in part means that the ear when laid 

 upon the chest feels an increase of the pectoral fremitus. Some- 

 times the voice as heard within the chest has a nasal, bleating tone, for 

 which phenomenon (cegophony) there is no satisfactory explanation. 

 Like the bronchial breathing sound, bronchophony ceases while the 

 tubes are obstructed by secretion, and while their communication with 

 the trachea is interrupted. During the process of resolution of pneu- 

 monia, moist rdles are heard. Sometimes, when the air again begins 

 to enter the minuter bronchi and vesicles, the rale is extremely fine, but, 

 as the secretion has less viscidity than before, the sound is not so " dry " 

 as that " crepitation " heard during the stage of engorgement This 

 sound is called the erepitatio redux. The rdles produced in the greater 

 bronchi, under conditions like those under which bronchial respiration 

 and bronchophony arise, may become bronchial " consonant " (Skoda) 

 and "ringing" rdles (Traube). 



The pleuritis which constantly accompanies pneumonia is not sus- 

 ceptible of physical demonstration, excepting when it causes a copious 

 effusion. There are scarcely ever any audible friction-sounds in the first 

 stage of pneumonia, since the pleural surfaces rub together very little, 

 if at all, at that period. They are heard somewhat oftener during reso- 

 lution, as tho air then reenters the vesicles, and the patients breathe 

 with greater freedom, producing friction of the pleural folds. 



The physical signs of a great cavity in the lungs, as a result of ab- 

 scess or gangrene, are identical with those of a tubercular cavity. For 

 a further description of them we refer to Chapter XIII. 



DIAGNOSIS. In children, and in greatly prostrated subjects, particu- 

 larly in old men, pneumonia is often overlooked. In children this occurs 

 chiefly when the disease sets in with convulsions and a violent fever, 

 attended by very little cough, as little children do not expectorate, nor 

 know how to tell the seat of their pain. Dyspnoea is then attributed 

 to the fever, and, if the child have diarrhoea, the fever is often regarded 

 as a " tooth fever," with inflammatory irritation of the intestinal mucous 

 membrane ; or, if the bowels be confined, it may be mistaken for acute 



