DISEASE OF THE MITRAL VALVE. 



371 



through the narrow passage produced in this disease. The sound is 

 all the louder, the more rapidly the blood pours in, and the rougher 

 and more uneven the surface over which it flows. As a longer time is 

 needed for it to pass through the contracted auriculo-ventricular orifice 

 to fill the ventricle, the murmur heard in mitral stenosis is of longei 

 duration than others, and almost always extends over the whole pause, 

 until cut short, as it were, by the next systolic sound. Traube there- 

 fore calls a " praesystolic " murmur at the apex a pathognomonic 

 symptom of stenosis of the mitral valve. If the contracted orifice be 

 not also roughened, if the stenosis be moderate, if the volume of the 

 blood be reduced, there may be no sound. In addition, we can, of 

 course, hear the second sound propagated from the arteries, unless the 

 murmur be too loud. Whether we hear the first sound, or a murmui 

 be audible in its stead, depends upon the efficience of the valve. The 

 second sound of the pulmonary artery is naturally considerably inten- 

 sified. 



TREATMENT. It is not to be supposed that we can cure yalvulai 

 disease of the mitral by any therapeutical interference whatever. 6 We 

 are equally helpless against the consecutive hypertrophy of the right 

 ventricle, which, however, has a beneficial action upon the distribution 

 of the blood. We are, therefore, reduced to a treatment of the more 

 prominent and dangerous of the symptoms. 



Hyperaemia of the lung is an inevitable consequence of mitral dis- 

 ease ; it cannot be averted nor permanently relieved. We should, 

 therefore, never interfere actively unless it be severe, or unless there 

 be danger of oedema of the lung. This is the more important, as 

 blood-letting, the only active remedy against hyperaemia, although for 

 the time it may ward off the peril, is extremely dangerous for the 

 patient. Perhaps, prior to the bleeding, there may have been no effu- 

 sion into the subcutaneous areolar tissue. Soon after it the blood will 

 have regained its former volume ; but its serum has now become so 

 much attenuated as to transude under a pressure which would not pre- 

 viously have caused transudation. The symptoms of dropsy often 

 first set in immediately after the first phlebotomy. Such "curse pos- 

 teriores," however, should not make us hold our hand, if the preserva- 

 tion of life really demand venesection (see chapter on pulmonary 

 hyperaemia and oedema of the lung). 



In digitalis we possess a very powerful means of moderating, not 

 only hyperaemia of the lungs, but also engorgement of the aortic 

 venous system which arises in mitral disease. If we can succeed in 

 retarding the action of the heart by means of digitalis, we afford time 

 to the auricle to drive its contents into the ventricle through the con- 

 tracted passage. Sometimes systole and diastole can be so greatlj 



