Some Disturbances of the Rhythm of the Heart.

The association of changes in the character of the pulse and serious cardiac symptoms was recognized many centuries ago, and carefully studied with all the means available at the time. But the significance of the arrhythmias has only been elucidated within the last few years, by the use of instrumental methods of analysis. In G. A. Gibson's text-book (1898), designed to be a mirror of the state of medical science and art at the close of the nineteenth century, only a couple of pages are devoted to the disturbances of the cardiac rhythm. James Mackenzie's book (1902) started an intensive study, and in his Morison Lectures, Gibson (1904) discussed paroxysmal tachycardia, extrasystole, and heart block. The study has continued, and our accumulated knowledge is now vastly greater than it was ten years ago, but there are still gaps on the clinical side. The following records are brought forward to augment the available data.