Fatty Degeneration Or Metamorphosis occurs in severe anemias, in phosphorous and arsenic poisoning, and in certain of the infections, as yellow fever. The liver is smaller than normal, yellow in color, and soft. Oil drops exude from the cut surface. Microscopically the cells are seen to contain numerous minute fat granules that do not, as a rule, tend to coalesce. Is most marked in acute yellow atrophy of the liver. In it the liver is greatly decreased in size, the edges thin, its color uniformly yellowish or streaked with brown, and is very soft, so much so that it may not retain its shape. The capsule is much wrinkled. On section the tissue in many places seems almost liquid, while elsewhere it is firmer and darker in color. Oil fairly drips from the surface. Microscopically the cells are seen to have undergone extreme metamorphosis, and to have been replaced by pigment. The hepatic tissue may be completely destroyed to a great extent; the degenerated material is absorbed and the decrease in size results.

Occasionally bright red or dark red areas are present. These represent foci of hemorrhagic infiltration or pigmentation.

The causes of this condition are practically unknown. It is most common in young women. It appears in infectious fevers, particularly puerperal, in syphilis, in phosphorous poisoning, and again without any apparent cause. Microorganisms of many kinds have been found in the bile-vessels and in the hepatic tissue, but no specific one has been isolated. Some authors think it due to the absorption of toxins from the intestine.

The destruction apparently begins in the peripheral zone around the portal vessel and extends toward the center.

The urine contains leucin and tyrosin.