MORBID ANATOMY 



383 



It may be uniform over the greater portion of the tube or 

 it may be limited to circumscribed patches. The commonest 

 seat of these lesions is near the blind end of the tube where it 

 evidently starts and whence it spreads to other portions. Not 

 infrequently only one cecum is dis- 

 eased, the other remaining normal. 



The affection of the cecum is due 

 primarily to the multiplication of the 

 microorganisrn which may take place 

 chiefly either in the mucous mem- 

 brane, or in the submucous tissue; it 

 may, though rarely; extend into the 

 muscular coat. The thickening of 

 the wall is the result of several 

 processes — the multiplication of the 

 parasites, the increase of the normal 

 tissue elements and later on the ac- 

 cumulation of masses of small cells 

 and some giant cells. 



In the early stages of the inva- 

 sion, the adenoid tissue between the 

 tubules and in the submucosa becomes 

 greatly increased, owing to the pres- 

 ence of large numbers of micro-para- 

 sites of round or slightly oval outline 

 and from 6 to lOyU in diameter which 

 stimulates the proliferation of the tis- 

 sue cells. Numerous mitoses have 

 been seen in this stage. The parasites 

 seem to occupy the meshes of the 

 adenoid tissue either singly or in 

 groups or nests. In these meshes 

 they are soon inclosed in cells acting 

 as phagocytes, so that the appearance 

 of an intracellular habitat of the parasites is suggested. 



The presence of the parasites in this reticulum probably 

 stimulates also the accumulation of lymph cells within the 



Fig. 99. Ceca of a turkey; 

 {a) and {6) are diseased 

 areas, (c) a section of the 

 thickened wall. 



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