MORBID ANATOMY 26 1 



slightly depressed below the surface. In some cases they are 

 uniformly whitish and shade off somewhat gradually into the 

 surrounding tissue. In sections of the affected organ it will be 

 found that the surface spots represent masses of liver tissue in 

 the same condition, the spots being simply the places where 

 these diseased foci intersect the surface. Some are found 

 deeply imbedded in the liver tissue, and therefore not visible 

 on the surface. The lesion of the liver is thus represented by 

 few or many foci of disease having in general a spherical form 

 and appearing on the surface of the organ as round spots. 

 Occasionally the lesions become more extensive and the death 

 of large Dortions of liver tissue follows. 



o J. 



The changes in the liver are most easily explained by 

 assuming that the microparasites are conveyed by the blood 

 directly from the diseased caeca into the liver and there de- 

 posited in different places, where they begin to multiply and 

 spread in all directions. In this way they form the spherical 

 foci of disease which appear as circles on the surface of the 

 liver. This theory is borne out by the results of the micro- 

 scopic examination. 



In sections of hardened tissue from the liver in which the 

 disease has but recently begun, the affected regions are invaded 

 by large numbers of protozoa which occupy a kind of reticu- 

 lum formed probably from the connective tissue stroma. The 

 liver cells have partially or wholly disappeared from these foci. 

 The parasites occupy the meshes of the tissue either singly or 

 in groups. The reticulum is provided with a small number of 

 nuclei, some of which are closely applied to and curved partly 

 around the parasite. The blood vessels are usually much 

 dilated and filled with red corpuscles. 



The yellow masses observed with the naked eye in the 

 surface spots are shown to be patches of an amorphous sub- 

 stance which take nuclear stains very feebly, the aniline colors 

 not at all. It may be described as a coarse network in the 

 meshes of which small cells, and very rarely parasites, are 

 seen. This substance is assumed to be the result of coagula- 

 tion necrosis of the liver cells by which they have lost their 

 nuclei and have become fused into a formless mass. It is 



