Experiments in animals have shown that removal of portions of the liver is followed by a regenerative growth of the various structures of the organ, this growth being by the usual process of Karyomitosis. The growth is not limited to the neighbourhood of the lesion, but the whole liver may take part in it. It has been stated by Ponfick that after removal of from a half to three fourths of the volume of the liver, there occurs in a comparatively short time such a compensatory hypertrophy of the rest of the tissue as to restore the original weight of the organ.

In man there are evidences of a similar power of compensatory hypertrophy and regeneration when portions of the liver are lost by disease or injury. In a case observed by the author there had been a congenital loss of a large part of the right lobe, apparently from some injury early in foetal life, as the right kidney was also wanting. In this case the left lobe was greatly increased in size, and the liver as a whole was of normal dimensions. A similar though probably more limited compensatory hypertrophy occurs from destruction of liver tissue in adult life. The destruction may be by syphilitic disease, by pressure of hydatids, by cicatrices, and even by cirrhosis. The region of the atrophy will determine that of the hypertrophy; sometimes the left lobe or the lobus Spigelii undergoes great enlargement.

There are some cases in which the liver as a whole is enlarged without any apparent alteration in structure, as if from a general hypertrophy. This is commonly the case in rickets. The liver is usually but not always enlarged in diabetes.

Literature

Hess, Virch. Arch., cxxi.; Meister, Centralbl. f. allg. Path., ii., 1891; Podwyssozki, Ziegler's Beitrage, i., 1886; Ponfick, Festschr. f. Virchow, 1891; Coats, Proc. Lond. Med. Soc, vii.