The Scottish cardiologist Sir James Mackenzie (1853-1925). He took his medical degree in Edinburgh, Scotland, and is well known for having developed new instrumental methods for the study of heart diseases. He devised improved instruments to record ink-tracings on paper of the pulses in arteries and veins. Mackenzie also found that some irregularities of the heartbeat were common and, in contrast with the accepted belief, not related to diseases. In 1908 he published the results of his studies in the Diseases of the heart that represented a milestone in cardiology. He reintroduced the use of digitalis, which contains digoxin, to treat heart failure.