Since the early days of the application of the string galvanometer to the study of the human heart, it has been known that in normal persons, on changing the position of the subject,1 there is a change in the form of the record as secured in the three leads. This is especially prominent in patients with cardiac disease. It is best seen on turning the individual in the reclining position from one side to the other. It was thought that this phenomenon might be of practical use in the diagnosis of adhesive pericardial mediastinitis, of which we have no thoroughly reliable clinical sign. Normal persons and patients have been examined from time to time during the last three years to test this possibility.
The change in the form of the electrocardiogram affects all of the waves present to a greater or lesser degree, but is most easily seen in the