The criteria that constitute the disease now spoken of as essential hypertension are not at all clear. It has become customary in clinical medicine to regard all persons with an arterial tension above normal as having potential hypertension. These are persons who normally exhibit a blood pressure above the average; the record given in table 1 is an example of a blood pressure reading of this sort.
The patient for whom the readings are recorded developed evident signs of hyperthyroidism after five years of observation. It may be that the high systolic, normal diastolic and increased pulse pressure, so characteristic of excessive activity of the thyroid gland, were throughout effected by this internal secretory disturbance, which did not manifest itself until some time later by the usual clinical signs of the condition.
Table 2 is another instance of prolonged blood pressure elevation. This record differs from the previous one in