588 THE LIVER. 



ATROPHY. 



Atrophy of the liver may affect the entire organ or be confined to 

 some part of it. General atrophy may occur in old age as a senile 

 change, or may be induced by starvation or chronic exhausting diseases. 

 The organ is diminished in size, is usually firm, and the acini appear 

 smaller than usual. Microscopically the change is seen to be due to a 

 diminution in size of the liver cells, and hand-in-haud with this there 

 occurs frequently an accumulation of pigment granules within the atro- 

 phied cells. The cells may entirely disappear over circumscribed areas, 

 leaving only shrivelled blood-vessels and connective tissue ; or, in some 

 cases, there may be an increase of connective tissue in connection with 

 the atrophy of the cells. When much pigment is formed in the cells the 

 lesion is often called pigment atrophy. 



Essentially the same changes may occur in circumscribed portions of 

 the liver, as the result of pressure from new connective tissue in cirrhosis, 

 from tumors, hydatids, amyloid degeneration, gall stones, etc. In at- 

 rophy from pressure the liver cells are apt to become very much flat- 

 tened and squeezed together as they diminish in size. 



DEGENERATION. 



Albuminous Degeneration. In the infectious diseases and in certain 

 cases of acute anaemia and phosphorus poisoning the liver is swollen 

 and, on section, of a dull yellowish-gray color, looking as if it had been 

 boiled. It contains less blood than usual, and the outlines of the lobules 

 are indistinct. Microscopical examination shows the lesion to consist of 

 a swelling of the liver cells and an accumulation in them of moderately 

 refractile, finer and coarser albuminous granules. These granules may 

 disappear and the cells return to their normal condition, or fatty degen- 

 eration may follow. Fatty and parenchymatous degenerations are often 

 associated. 



Focal necrosis of liver cells occurs in many acute infectious diseases 

 (see page 201). 



Acute Yellow Atrophy (Acute Parenchymatous Degeneration). This rare 

 disease is characterized anatomically by a rapid diminution in the size 

 of the liver as the result of a granular and fatty degeneration and disin- 

 tegration of the liver cells. The liver, sometimes within a few days, 

 may be reduced to one-half its normal size. On opening the abdominal 

 cavity the organ may be found lying, concealed by the diaphragm, close 

 against the vertebral column. The amount of diminution and the gen- 

 eral appearance of the affected organ depend to a considerable extent 

 upon its previous condition i.e., whether or not it was the seat of other 



1 For a study of necroses of the liver see Mallory, Jour, of Med. Research, vol. vi., 

 1901, p. 264. 



