The orders Columbæ and Fulicariæ are missing from the list of Aves having arterial disease, yet a reasonable number of autopsy records are at hand. SUMMARY ON ARTERIOSCLEROSIS. Having discussed the orders separately, a review of the whole situation is desirable. Chronic arteritis, or as it is usually called arteriosclerosis, is common to very many zoological orders, and its principal lesions are comparable throughout the two classes under consideration. A statement as to its incidence would best be made by adopting an arbitrary number of observations as the desired minimum upon which to draw conclusions, and I shall adopt one hundred as such a figure. Accepting this as reasonable, a review of the table indicates that the order of percentage incidence is: Accipitres 6.6, Ungulata 3.5, Anseres 3.4, Carnivora 3.3, Striges 2.2, Psittaci 1.8, Marsupialia 1.8, Galli 1.6, Primates 0.6, Passeres 0.22; the other orders have less than one hundred specimens each. There is no doubt that carnivorous birds have the highest incidence of chronic arterial disease. Next in order come three varieties with nearly equal incidence, the ungulates, anserine birds and carnivorous mammals. These orders have little in common unless it be that in nature they are often engaged in prolonged or strenuous effort, as in fight or flight. We possess no measurement of their vascular supply but by consultation of the table giving heart weights (page 63) it will be found that three of them have values below that of the class in which they belong; the Carnivora alone have a greater heart-to-body ratio than the average for its class Mammalia. Nor do these orders have any direct dietetic relationship. The expected longevity of these groups does not permit one to discover any reason for arterial changes except perhaps that they have a reasonably good viability under park conditions, and therefore many have a longer opportunity to develop vascular disease. It so happens, however, that the first four groups are the most likely to suffer from gastrointestinal inflammation, of dietetic or bacterial origin. It is interesting, but not easily explicable that the orders of great activity, Primates and Passeres, are at the end of the list; their food is very largely carbohydrate in character. Just why Lemures, Rodentia and Columbæ should be missing is not quite clear, because orders of comparative habits and food are included. A review of the concomitant pathology reveals the fact that nephritis more often accompanies these processes than any other single condition. Among the chronic infectious disease in the table is included chronic enteritis; this group falls well behind the renal diseases. The relatively small number of cases of valvulitis speaks rather against an active infectious origin of the vascular lesions. ANEURYSMS.