594 SPORADIC DISEASES. 



3. A bellows murmur with the second sound indicates aortici 

 insufficiency ; roughened auricular surface of the mitral valves, 

 or mitral obstruction. The most common sound heard in tlie 

 horse is a murmur masking or hiding the second sound, and 

 indicating semilunar insufficiency. When the murmur is double, 

 occupying the periods of both cardiac sounds, it indicates mitral 

 obstruction and insufficiency. 



The sounds of the heart may be seemingly intensified by 

 consolidation of the lungs and by hydrothorax, and diminished 

 by emphysema of the lungs. In some instances of consolidation 

 the sounds may be more distinctly heard on the right than on 

 the left side : this indicates hepatization of the right lung, with 

 compensating dilatation of the tubes of the left one. 



Metallic tinkling, coincident with the cardiac impulse, is some- 

 times associated with the booming sounds of endocarditis. 



PEECUSSION IN DISEASE 



Supplementary to auscultation, percussion is a valuable aid to 

 diagnosis, more especially of pleural and pulmonary diseases. 



1. Increased resonance indicates dilatation of the bronchial 

 tubes and air vesicles ; if partial or confined to one side only, 

 and if associated with dulness of the opposite side, increased 

 resonance may merely indicate a compensatory respiratory effort. 

 In such a case the respiratory murmur will also be increased. 

 Augmented resonance is, however, generally associated witli 

 decrease or absence of the true respiratory sounds, and accom- 

 panied with wheezing, creaking, crackling crepitations, indicative 

 of pulmonary emphysema, as in broken wind, rupture of the air 

 cells, and chronic bronchitis. 



2. Diminished resonance indicates consolidation of the lungs, 

 hydrothorax, pleural exudations, tubercles, congestion of the 

 lungs, pulmonary apoplexy, &c. When confined to the inferior 

 parts of the chest, replaced abruptly superiorly by increased 

 resonance, it is diagnostic of hydrothorax. When the dulness 

 gradually disappears, it is indicative of hepatization of the lung 

 tissue, being greatest where the consolidation is most complete. 



It is stated that enlargement of the heart is indicated by an 

 increased area of cardiac dulness ; for my own part, I have never 

 been able to make this out. 



