208 COCCIDIUM OVIFORME. 



cavity, with the above-described caseous or cream-like contents, but 

 they have further no columnar epithelium. This has been replaced 

 by more or fewer round cells, which lie in a thick layer on the con- 

 nective tissue sheath, and resemble round granules in appearance 

 (Figs. 108 and 109). This is especially true of the larger cells, which 

 measure - 03 mm. and more in diameter, and not unfrequently project 

 more or less above their surroundings. 



Another difference consists in the fact that the connective tissue 

 clothed with these cells is not only pushed out into numerous recesses, 

 but is also raised into folds, which run longitudinally and often in- 

 trude far into the inner space. In some places it is so much occupied 

 by these inwardly projecting folds that there are left only one or 

 two usually peripheral lateral spaces (Fig. 108). 



- 



FIG. 108. Cross section of a Coccidium-nodule, slightly enlarged. The contents have 

 been for the most part washed out. 



On cross section the folds are very like papilloinatous elevations, 

 especially when they are low and, as sometimes happens, forked like 

 a Y- It is thus not difficult to understand how they have been hitherto 

 very generally described as such. Many of them may indeed repre- 

 sent exuberant growths of this kind, but the majority are undoubt- 

 edly nothing but the remains of the septa that separated the bile- 

 ducts which were originally more numerous. It is a mistake to refer 

 the nodules to a single much-distended bile-duct for the nature of 

 their origin, as above described, and the character of the intermediate 

 stages, show them to be formed from several closely connected bile- 

 ducts, which, being similarly altered, may gradually coalesce through 

 the more or less perfect disappearance of the dividing walls ; and we 

 need not point out how the presence of the side-chambers, hitherto 

 almost entirely overlooked, thus finds its natural explanation. 



The intermediate stages, to which we have just referred, furnish 



