Wild animals do not give evidence of repeated attacks of acute disease and indeed it would seem that they more often die of an acute infection than live to have it repeated. Evidences of chronic infection, not focal, are reasonably definite in forty-eight per cent. of the cases of chronic nephritis encountered here. This suggests strongly that in this material protracted infectious states offer opportunities for renal damage of progressive character. Vascular disease has been found twenty- eight times (see also section on arteries), in twenty-six of which the nephritis seemed due to or advanced by the damage to the vessels. This means further that only 14.3 per cent. of the chronic forms and 4 per cent. of the total seem closely related to disease of blood vessels. Nephritis has been found in 12.2 per cent. of our total autopsies. Mammals show an incidence of 20.6 per cent., birds 7.7 per cent. Only the orders upon which more than one hundred autopsies have been held are subjected to separate analysis. Some of the remaining orders give very high figures which may indicate great renal vulnerability but it is deemed unfair to make statements upon them. Carnivorous mammals and birds lead their respective classes, the succeeding order of renal vulnerability being marsupials, ungulates, rodents, Primates, Galli, Striges, anserine birds, parrots, and doves. The leaders of this list, Carnivora and Accipitres, occupy a definite position in the analysis of acute and chronic lesions. Their kidneys show the smallest percentages of acute lesions and the highest percentages of chronic lesions. This would seem to indicate a resistance to acute injuries but susceptibility to prolongated or repeated infections or intoxications. The relation of chronic infection of some sort to chronic renal disease is not as clear as the influence of acute infection to acute nephritis. Taking Carnivora for example with 34.2 per cent. of chronic nephritis we find 22.4 per cent. with evident chronic inflammation while in the 55 per cent. of acute forms 40 per cent. are of acute infectious origin—the relation is as 64 is to 74. While the relation of infection to nephritis is a consistent and perfectly acceptable one, the frequency of this disease in the carnivorous orders obliges one to think of high protein diet as a favoring factor. Renal disease is common enough in other orders, some strictly herbivorous, and it is fair only to emphasize which are the leaders in incidence. In so far as anatomy or habits are concerned no generalizations seem permissible. There is no relation of nephritis to the size of the kidney as given on a previous page, to the length of the alimentary tract, or to the expected longevity.