Page:Popular Science Monthly Volume 25.djvu/209

Rh and fairly expressive of sounds actually and distinctly heard, for which a verbal rendering is necessary.

The loudness and clearness of the murmurs are by no means proportionally indicative of their gravity; since one barely audible may from its location and character be a low premonition of mischief, while a more demonstrative one may have no important significance.

In a rare case, a musical murmur was heard exactly resembling the notes of the cuckoo; it was so loud as not to be the exclusive property of stethoscopists, for it could be heard at a distance of several feet. Moreover, it was shown by the "demonstrator," post longam vitam, that the heart whence the sound had proceeded was entirely free from all organic disease.

The mechanism concerned and the method of determining the kind and location of a murmur may be referred to very briefly.

As an example, organic disorder of the aortic semilunar valve will be presumed. Imperfections of this valve are among the more frequent diseases of circulation, and are of import more or less serious according to their extent; its total failure nullifies every anatomical perfection in all the other organs of circulation.

With the stethoscope suitably placed, a distinctly audible murmur will be detected. On observing the rhythmic succession of "first" and "second" sounds the murmur will be found to occur exactly with or in place of the latter, whose sudden click will at least be notably weakened. The murmur is found over the position of the semi-lunar valve and extending downward in a line toward the middle of the chest; it is slightly prolonged after the "second sound." No other murmurs are discovered. These are sufficient data for a diagnosis.

The observer has seen, as it were, two ounces of blood destined for the wants of the system driven through the semilunar gateway into the great vessels; this movement was accompanied by the normal booming "first sound" and was attended by no murmur. There was, then, no obstruction or narrowing of the orifice, nor roughness of the valve, that by consequent vibrations could produce a murmur. But the observer has seen the measure of blood, under the elastic pressure of the vessels, returned upon the semilunar valve for momentary support, where, instead of being promptly arrested by the three-winged leaflets, a portion passed between their narrowed or irregular edges into the heart, and at this instant of regurgitation the murmur was heard. The blood could flow unobstructedly from the heart, but its unfavorable retroversion was made possible by the organic imperfection called insufficiency of the semilunar valve of the aorta.

The sphygmograph alone would have written the above diagnosis in this uncomplicated case with entire completeness, and its tracings would have shown also, as a part of the pathological history, that the valvular defect originated many months ago; that, through the natural curative processes the heart had gradually increased in strength