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XIII] is the existence of a generalized fatty degeneration of the capillaries and smaller blood-vessels. The stomach, as stated, always contains more or less black material, sometimes fluid blood, such as may have been vomited during life. The folds of the gastric mucosa are swollen ; here and there are arborescent patches of congestion, and ecchymoses. Observers are not agreed as to the nature of this congestion— whether it is passive or inflammatory. Sternberg says that in the increase of leucocytes in the sub-mucosa there is evidence of a slight inflammatory action. The small intestine may contain a dark, acid material similar to that in the stomach, and doubtless coming from the same source. Like that of the stomach, the mucous membrane of the intestine shows patchy arborescent injection. As compared with other fevers, in yellow fever the liver is characteristically affected. As a rule, if death has occurred at the later stages, this organ is somewhat exsanguine, friable, and presents a yellowish colour from profound fatty changes in the cells. Occasionally, though rarely, it may be hyperæmic and dark. Throughout the gland the cells particularly those about the periphery of the lobules— on microscopical examination are found to contain globules and grains of fat. The nuclei in some instances, as well as the protoplasm of the cells, show fatty changes; the latter may be completely disintegrated. In the great majority of cases this fatty degeneration is well marked. It is not confined to the liver; every organ of the body is more or less affected in the same way.

The spleen is not characteristically affected, but the kidneys show signs of parenchymatous nephritis. Hæmorrhagic foci under the capsule and in the cortex are common. The renal epithelium shows cloudy swelling passing on to fatty degeneration and desquamation. The tubules, here and there, are filled with infarcts, either of an albuminoid material or of débris of desquamated epithelium, corresponding with the numerous casts which can be discovered in the albuminous urine.