WITH THE general increase in life expectancy, the problem of caring for arteriosclerotic aneurysms arises in many clinics. Of the aortic aneurysms, the thoracic ones can be recognized earlier, and since they are often syphilitic the tissue response to various attempts at obliteration is more intense. On the other hand, the abdominal aneurysms of the aorta may run a long, asymptomatic course1 and are far oftener arteriosclerotic2; in them the degenerated wall with its poor blood supply offers added difficulties.
While the syphilitic, arteriosclerotic, and mycotic types of aneurysm can be held apart with fair certainty (recognizing, of course, combinations of several varieties in the same vessel), little attention has been paid, at least in this country, to the cystic medial necrosis of Erdheim,3 a lesion which consists of patches of muscle necrosis or cysts filled with mucoid material. This lesion may be found even far away