The arteries in these young adults were remarkably healthy, and in none of them did we observe the characters of arteriosclerosis or leutic lesions. On the other hand, evidence of superficial fatty streaks lying in the intima of the aorta and some of its large branches were not uncommon and are believed to have had a relation to the acute infection of which they died. In only four cases in the series of 32 autopsies was evidence of these fatty streaks wanting. In about one-half of the remaining number these fatty streaks were only slight or moderate in extent, while in the rest of them these lesions were particularly prominent and striking. They formed linear markings on the posterior wall of the aorta, aggregating with particular prominence about the intercostal arteries. The anterior wall was quite free from them. The greater extent of these lesions lay in the descending thoracic and was less marked in the arch and the abdominal aorta. At times these fatty streaks were found to extend into the large vessels of the neck and into the intercostal arteries, and they were also found in the coronaries of the heart. It was uncommon to observe their presence in the arteries of the abdominal viscera. This type of lesion has been discussed from the standpoint of its etiology and its possible bearing upon true arteriosclerosis. Some believe that the frequency of its finding in autopsy material suggests the non-importance of its presence. This we can hardly agree with. It is true that the presence of these lesions does not materially incapacitate the aorta in acting as the main channel for the distribution of blood. The lesions are quite superficial in the intima and cause but little elevation on the surface. The amount of roughening which the intima presents to the blood is not great. Nevertheless, the presence of these fatty streaks is an index of the disturbed metabolism of the cholesterin products of the body. Under certain conditions they make their appearance when there is a true hypercholesterinemia such as is readily produced in the animal experiments by feeding cholesterin. Under these circumstances the various tissues of the body, including the adrenal, the corpus luteum, the spleen, liver and arteries, all participate in localizing cholesterin in the form of cholesterin-ester in peculiar cells which have been termed cholesterin-ester phagocytes. It has been shown that cholesterin metabolism is quite readily altered in the human and that the blood content will vary from the normal. In chronic kidney disease, pregnancy, diabetes, chronic heart disease and arteriosclerosis the blood cholesterin rises, while in many of the acute infectious diseases the cholesterin in the blood is materially diminished. It is particularly in these latter cases where fatty streaks of the intima are prone to occur. Hence in human pathology we more often meet with the development of fatty streaks of the intima associated with a