88 CLINICAL DIAGNOSTICS. 



cal changes of the heart itself, they are called organic, other- 

 wise inorganic. 



a. The organic or endocardial heart bruits are caused 

 either by a narrowing (stenosis) of the atrio-ventri- 

 cular or arterial openings or by alterations on the valves pre- 

 venting them from closing properly (insufficiency). 

 They form most valuable symptoms in the diagnosis of heart 

 diseases. 



In stenosis the bruit occurs at the moment 

 the blood passes the contracted orifice, the 

 walls of which are set in vibration. If the stenosis involves 

 the atrio-ventricular opening the bruit occurs at diastole, if 

 in the arterial openings, at systole. 



In insufficiency the bruit occurs at the 

 moment at which the valves should close. In 

 consequence of their inability to close a regurgitation of the 

 blood takes place, which produces a renewed vibration of the 

 valves, and gives a bruit. If the insufficiency involves the 

 atrio-ventricular valves, the bruit occurs at systole ; if the 

 semilunar valves are insufficient the bruit appears at diastole. 



The character of the bruits is varied, they can be buz- 

 zing, blowing, purring, hissing, humming, sazving, rattling, 

 long or short tones. Insufficiency bruits are generally softer 

 than those due to stenosis. Heart bruits are made more 

 pronounced by an acceleration of the heart's action, therefore 

 the patient should be exercised before examination. 



Gmelin recommends digitalinum verum subcutaneously to 

 bring out more distinctly heart sounds or casual bruits. The dose 

 for the horse and ox is 0.02S— 0.0S; for the dog 0.002 —0.009. The 

 digitalin is first dissolved in Seem of 50% alcohol and then diluted 

 with 20ccm of water. 



