Arteriosclerosis is essentially a disease of middle life and old age. It is not unusual, however, to find evidences of the disease in persons in the third decade and even in the second decade. Hereditary influences play a most important rôle, syphilis and the abuse of alcohol in the family history are particularly momentous. The recognition of the early changes in the arteries among young persons depends largely upon how carefully these changes are looked for. The difference in the point of view of one man who finds many cases in the comparatively young, and another man who rarely finds such changes early in life, at times, depends upon the acuity of perception and observation and not upon the fact that one man has had a series of unusually young arteriosclerotic subjects. The diagnosis of arteriosclerosis may be so easily made that the tyro could not fail to make it. It is, however, the purpose of this volume to lay stress on the earliest possible diagnosis and, if possible, to point out how the diagnosis may be arrived at. It is obviously much to the advantage of the patient to know that certain changes are beginning in his arteries, which, if allowed to go on, will inevitably lead to one or more of the symptom groups described in the preceding chapters. The combination of (1) hypertrophied heart, (2) increased blood pressure, (3) palpable arteries, and (4) ringing, accentuated second sound at the aortic cartilage is, in reality, the picture of advanced arteriosclerosis. If the individual is in good condition much may be done by judicious advice and treatment to ward off complications and prolong life with a considerable degree of comfort. But we should not wait until such signs are found before making a diagnosis and instituting treatment. As in all forms of chronic disease the early diagnosis is all important. The history of the case is the first essential. Often a careful inquiry into the personal habits of a patient, with the record of all the preceding infectious diseases will give us valuable information and may be the means of directing the attention at once to the possible true condition. Particularly must we inquire into the family history of gout and rheumatism. An individual who comes of gouty stock is certainly more prone to arterial degeneration than one who can show a healthy heredity. Alcoholism in the family also is of importance because of the fact that the children of alcoholics start in life with a poor quality of tissue, and conditions that would not affect a man from healthy stock might cause early degeneration of arterial tissue in one of bad ancestry.