Blood pressure rises in response to many stimuli in both normal and hypertensive persons. It is well known that the response is greater in patients with essential hypertension than it is in normal persons. In an attempt to devise a standard stimulus for measuring this reaction, Hines and Brown1 developed the cold pressor test. More recently Ayman and Goldshine2 described a breath-holding test for use as a standard blood pressure stimulus. They concluded that there was a "striking similarity" in the reactions of the blood pressure to the cold pressor and breath-holding tests. In their series the breathholding test, as a general rule, showed a greater reaction. Since the breath-holding test requires no special equipment, Ayman and Goldshine felt it might well be used in place of the cold pressor test. In order to compare the two tests, the reactions of 200 persons, some with normal and some