This 37-page pamphlet was the earliest collection of information regarding electrocardiography. It contained "only single lead electrocardiograms, limited to mitral stenosis and hypertrophy of the right and left venticles; arrhythmias were not shown" (Shapiro, "The first textbook of elecrocardiography. Thomas Lewis: Clinical electrocardiography," J. Am. Coll. Cardiol., 1 (1983) 1160-61).