It is much more dangerous for the patient when the process is in the ascending portion of the arch of the aorta than when it has attacked the peripheral arteries. Here, at the root of the aorta, are the openings of the coronary arteries and the arteries supplying the brain are close by. The coronary arteries here control the situation. When loud murmurs are heard at the aortic orifice and the heart is evidently diseased, it is useful to divide the endocarditis into two types, the arteriosclerotic and the endocarditic. The etiology of the former is sclerosis and the prognosis is grave because of the liability, nay the probability, that the orifices of the coronary arteries will become narrowed. The etiology of the second type is in most cases rheumatic fever or some other infectious disease, and the prognosis is far better than in the first type. True, the two may be combined. In such a case, the prognosis is entirely dependent upon the course of the arteriosclerosis. The involvement of the arteries in the kidneys is of considerable importance, for it is usually bilateral and widespread. As a rule, the disease makes but slow progress provided that the general condition of the patient is good, but at any time from a slight indiscretion or for no assignable cause, symptoms of renal insufficiency may appear and may rapidly prove fatal. It must not be thought that because the localization of the arteriosclerosis in the peripheral arteries is usually the most favorable condition that it is therefore devoid of ill effects. On the contrary, very serious, even fatal, results may be brought about by interference with the circulation with resultant extensive gangrene of the part supplied by the diseased arteries. The amputation of a portion of a leg, for instance, may relieve, to some extent, an overburdened heart and prove life-saving to the patient, but the neuritic pains are not necessarily relieved. The torture from these pains may be excruciating. No stage of the disease is exempt from its particular danger. In the early stages of the disease before the artery or arteries have had time to become strengthened by proliferation of the connective tissue, there is the danger of aneurysm. Later, the very same protective mechanism leads to stiffening and narrowing of the arteries and hence to increased work on the part of the heart with all of its consequences. Thrombosis is favored, and where atheromatous ulcers are formed, embolism is to be feared.