The rate of the heart varies widely in normal persons and may be increased temporarily by many different causes. Among them are excitement, exertion, pain, the ingestion of food, the drinking of coffee or tea and the smoking of tobacco. Acceleration is observed also in numerous states of disease, such as thyrotoxicosis, infection, shock and hemorrhage. Transient tachycardia due to emotional disturbance, when the only sign of a disordered cardiovascular system, has not been considered clinically important. No careful analysis of this condition has been found in a survey of the literature. In monographs on diseases of the heart only casual mention is made of it. In the booklet on "Standards of Physical Examination During Mobilization" (MR 1-9), issued by the War Department on Oct. 15, 1942, it is specified that a heart will be considered normal when there is "a pulse rate of 100 or over which is not