THE LIVER. 605 



doubtless in part are, brought to the organ through the portal vein ; but 

 they may, in part at least, be formed hi the liver itself, possibly from 

 the capillary endothelium. 



In typhoid fever, smallpox, scarlatina, diphtheria, and measles small 

 circumscribed masses of spheroidal cells are sometimes found in the 

 liver. These nodules differ in character, some are due to focal necroses, 

 such as occur in various toxaemias with a later multiplication of cells or 

 invasion of leucocytes. In some, as in typhoid fever, there is necrosis 

 with proliferation of endothelium (see page 232). Finally some of the 

 small masses of spheroidal cells encountered in the liver in infectious 

 diseases are doubtless hyperplastic lymph-nodules. 1 



TUMORS OF THE LIVER. 



Tumors of the liver may be primary or secondary ; the latter are most 

 common. 



Cavernous Angiomata. These tumors, usually small, are most common 

 in elderly persons and are of no practical significance. They may be 



FIG. 369. CAVERNOUS ANGIOMA OK THE LIVER. 



situated at the surface (Fig. 369) or embedded in the organ, and are of 

 a dark-red color; sometimes sharply circumscribed by a connective- 

 tissue capsule, sometimes merging imperceptibly into the adjacent liver 

 tissue. Microscopically they consist of a congeries of irregular cavities 

 (Fig. 180, page 833) filled with blood and frequently communicating 

 freely with one another. The walls of the cavities consist of connective 

 tissue, often containing small blood-vessels, and are sometimes thick, 



1 For changes in the blood iu diseases of the liver consult Ewing's "Clinical Path- 

 ology of the Blood." 



