Stone[11] has divided the cases of hypertension into the cerebral and cardiac types. He finds that there is a difference in prognosis and in the mode of death in the two groups. He has further attempted to judge of the work placed upon the heart by calculating what he calls the heart load or pressure-ratio. For example, he takes a normal pressure at 120-80-40. The relation between 80 and 40 is 1/2 or 50 per cent. That he considers normal. When the heart load increases so that the pulse pressure equals or exceeds the diastolic pressure, the heart load is 100 per cent or more, he considers the danger of myocardial exhaustion graver than when the heart load is normal or less than 50 per cent. [11] Stone, W. J.: Arch. Int. Med., 1915, xvl, 775. It is his opinion, in which I heartily concur, "that an individual with a systolic pressure of 200 and a diastolic pressure of 140, is in greater danger of cerebral death than an individual with a systolic pressure of 200 and a diastolic pressure of 100." He is "likewise certain that the individual with a systolic pressure of 200 and a diastolic of 90 to 100 is in greater danger of a cardiac death. It is apparently the constant high diastolic pressure rather than the intermittently high systolic pressure which predisposes to cerebral accident." I have not been able to confirm all of Stone's conclusions. His contention holds good for some cases, but not, in my experience, for the great majority of the hypertension cases. I feel that in the classification of the chronic high pressure case we can go one step farther and split his first group into two usually differentiable groups. Syphilis is not an etiological factor in any of these groups. It is not considered that these groups are absolutely distinct and can always be rigidly separated. There are variations and combinations which render an exact separation impossible. But bearing this in mind the following classification is proposed as a working classification. Group A. Chronic nephritis. Group B. Essential hypertension. Group C. Arteriosclerotic hypertension. Group A. _Chronic Nephritis._ These are the cases with a high-pressure picture, that is to say, high systolic (200+) and high diastolic (120-140+). The pulse pressure is much increased. The palpable arteries are hard and fibrous. There is puffiness of the under eyelids, which is more pronounced in the morning on arising. Polyuria with low specific gravity and nycturia are present. There are almost constant traces of albumin in the urine, with hyaline and finely granular casts.