HYPERTROPHY OF THE HEART. 



325 



many authorities also describe a region of flatness, which is found 

 where a thin layer of lung lies between the heart and the thoracic 

 wall, and indeed a dispute has arisen between them, as to which of 

 these percussion-signs is entitled to the name of cardiac dulness, and 

 which that of cardiac flatness. Such niceties and disputes over names 

 are of no practical use. They neither benefit the patient nor promote 

 the progress of science. 



Auscultation. We follow JBamberger's account of the normal 

 sounds of the heart. According to him, the first sound, that which is 

 heard simultaneously with the heart-stroke, and which corresponds with 

 the systole of the ventricle, is produced both in the ventricles and in 

 the arteries : in the ventricles, by the sonorous vibrations into which 

 the tricuspid and mitral valves are thrown, when placed in a state of 

 tension by the blood as it is forcibly expelled ; in the pulmonary artery 

 and aorta, by the sound created by the distention and stretching of the 

 walls of those vessels by the passage of the blood-wave. We are 

 forced to the latter supposition, by the circumstance that we can hear 

 a systolic sound in all the larger arteries, even at a distance from the 

 heart, which could not possibly be propagated from the ventricles, 

 whenever the vessels are much distended. The second heart-sound, 

 which is heard during the diastole of the ventricle, and which is sepa- 

 rated from the previous one by a short pause, and from the sound 

 which follows by a more extended interval, is produced in the arteries 

 alone. Although it is audible in the region of the heart, yet it is con- 

 ducted thither, as no sound can well arise in the heart itself during its 

 diastole. Its source is in the arteries, where it is created by the flap- 

 ping of the semilunar valves, which are put on the stretch by the 

 diastole, and receive a shock from the blood which is driven against 

 them. The heart-sounds are never altered nor converted into mur- 

 murs by simple hypertrophy. On the contrary, when the heart is 

 hypertrophied, the sounds are more distinct and louder, the mitral and 

 tricuspid valves being exposed to heavier concussion and thrown into 

 stronger vibration, the aorta and pulmonary artery being fuller, and 

 nence vibrating more actively, owing to the additional flow of blood 

 which they receive, and to the greater shock falling upon the semilunar 

 valves from increase of the arterial contents. When there is much 

 hypertrophy, a peculiar metallic sound is audible (cliquetis me'tallique) 

 during systole, which appears to come from vibration of the thorax. 



DIAGNOSIS. Not only are the subjective signs of hypertrophy of 

 the heart, and their concomitant derangements of the circulation, liable 

 to be overlooked, but even the physical signs may fail to reveal the 

 existence of the malady. When the left lung is emphj^sematous, and 

 intervenes between an enlarged heart and the thoracic wall, there is 



