LIVER ACUTE YELLOW ATROPHY. 393 



rectum, the caecum, and flexures of the colon. It usually pre- 

 sents as a solitary, soft, often ulcerating, fungous mass, which 

 projects into the lumen of the intestine (Fig. 183). 



Microscopically, the adeno-carcinoma or cylindrically-celled 

 cancer is the variety most frequently noted. 



Connective-tissue tumors are not often found in the intestinal 

 tract. 



THE LIVER. 



PASSIVE HYPER^IMIA. 



Passive hyperaemia is produced by some obstruction to the 

 circulation through the hepatic vein, as by a large pleuritic 

 effusion; intrathoracic tumors, cirrhosis of the lungs; and 

 especially valvular disease of the heart. At first the liver is 

 often considerably enlarged ; on section, it has a peculiar 

 mottled or nutmeg appearance, the darker congested areas 

 around the central hepatic vein of the lobule contrasting 

 markedly with the lighter periphery, which may be yellowish 

 or yellowish-white from advancing fatty degeneration. At a 

 later stage the liver is decreased in size, from atrophy of the 

 parenchyma-cells produced by the excessive pressure of the 

 blood ; and there may be very considerable hyperplasia of the 

 connective tissue, giving the organ a slightly roughened or 

 uneven surface. 



Microscopically, the central hepatic vein and surrounding 

 capillaries are greatly dilated and engorged with blood. In 

 the centre of the lobule the rows of liver-cells between the 

 dilated capillaries are entirely atrophied. In the peripheral 

 zone of the lobule there is often an advanced fatty degenera- 

 tion. 



ACUTE YELLOW ATROPHY. 



Acute yellow atrophy of the liver occurs as an independent 

 specific disease ; or secondarily to phosphorus-poisoning, 

 typhoid fever, puerperal septicaemia, and other infectious 

 diseases. As an independent affection, however, it is ex- 

 ceedingly rare. 



Anatomically, the characteristic feature of the disease is the 



