322 INFECTIOUS ENTERO-HEPATITIS 
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 visi- 
«| ble 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 portions of 
3) liver tissue follows. 
| The changes in the liver are 
most easily explained by as- 
Fic. 74. A DRAWING OF a BEGINNING NECRO- suming that the micropara- 
TIC MASS. (a) GIANT CELLS, (c) FREE NUCLEI, —- t at th 
AND (b) DISINTEGRATED NEcRoTIC Tissuz. SIU€S are conveye y e 
blood directly from the dis- 
eased ceca into the liver and there deposited 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 num- 
bers of protozoa which occupy a kind of reticulum formed probably 
& : \ 
Fic. 75. AREAS OF NECROSIS IN LIVER. Fic. 76. CROSS SECTION OF CECUM. 
from the connective tissue stroma. The liver cells have partially or 
wholly disappeared from these foci. The border of the necrotic 
tissue is surrounded by a zone of giant cells. The parasites occupy 
the meshes of the tissue either singly or in groups. The reticulum is 
