Katzenstein [Footnote: Katzenstein: Deutsch. med. Wehnsehr., April 15, 1915.] finds, after ten years of experience, that the following test of the heart strength is valuable: He records the blood pressure and pulse, and then compresses the femoral artery at Poupart's ligament on the two sides at once. He keeps this pressure up for from two to two and one-half minutes, and then again takes the blood pressure. With a sound heart the blood pressure will be higher and the pulse slower than the previous record taken. If the blood pressure and pulse beat are not changed, it shows that the heart is not quite normal, but not actually incompetent. When the blood pressure is lower and the pulse accelerated, he believes that there is distinct functional disturbance of the heart and loss of power, relatively to the change in pressure and the increase of the pulse rate. He further believes that a heart showing this kind of weakness should, if possible, not be subjected to general anesthesia. Stange [Footnote: Stange: Russk. Vrach, 1914, xiii. 72.] finds that the cardiac power may be determined by a respiratory test as follows: The patient should sit comfortably, and take a deep inspiration; then he should be told to hold his breath, and the physician compresses the patient's nostrils. As soon as the patient indicates that he can hold his breath no longer, the number of seconds is noted. A normal person should hold his breath from thirty to forty seconds without much subsequent dyspnea, while a patient with myocardial weakness can hold his breath only from ten to twenty seconds, and then much temporary dyspnea will follow. Stange does not find that pulmonary conditions, as tuberculosis, pleurisy or bronchitis, interfere with this test. Williamson [Footnote: Williamson: Ant. Jour. Med. Sc., April, 1915, p. 492.] believes that we cannot determine the heart strength accurately unless we have some method to note the exact position of the diaphragm, and he has devised a method which he calls the teleroentgen method. With this apparatus he finds that a normal heart responds to exercise within its power by a diminution in size. The same is true of a good compensating pathologic heart. He thinks that a heart which does not so respond by reducing its size after exercise has a damaged muscle, and compensation is more or less impaired. Practical conclusions to draw from the foregoing suggestions are: 1. An enlargement of the heart after exercise can be well shown only by fluoroscopic examination, and then best by some accurate method of measurement. 2. The blood pressure should be immediately increased by exercise, and after such exercise should soon return to the normal before the exercise. If it goes below the normal the heart is weak, or the exercise was excessive. 3. The pulse rate should increase with exercise, but not excessively, and should within a reasonable time return to normal.