41 



lesions. It is a question whether this necrobiosis is the result oi' 

 some secretion of the amoebae or whether it depends more upon 

 throinbus formation. In some places the latter seems to be the 

 predominating factor, in others the former, while in still others 

 neither appears to influence the process. It is, however, certain 

 that the thrombosis assists the amoebae in extending their zone of 

 action, as it may likewise assist the bacteria. 



Necessarily the contents of the ulcers vary according to the 

 degree of ulceration and to the character of the bacteria present. 

 In uncomplicated cases, which microscopically show a rather clear, 

 yellowish, gelatinous material in the opening, the ulcer contents 

 are composed of a granular base of albuminous character, in which 

 cells in various stages of degeneration are imbedded, together with 

 amoeba}, bacteria, and usually a few red blood corpuscles. 



In all the lesions the amoeljse vary widely in size. Measured 

 with a Zeiss schrauben micrometer they range between 4 and 35 m. 



In the earliest stages of the amoebic invasion, the oedema effects 

 the submucosa. In the later ones the subperitoneal coat is also 

 involved and adds considerably to the thickness of the gut. Eosin- 

 ophiles are not uncommon in either the modified or unmodified 

 amoebic process. They occur for the most part in tissues at some 

 distance from the lesions, usually in the neighborhood of blood 

 vessels, and are not uncommonly encountered in the subperitoneal 

 connective tissue, when that layer has become ocdematous. These 

 are perhaps more numerous in the secondary infections, as are 

 also mast cells. Plasma cells are frequently seen in the submucosa. 

 In the most extensive ulcerations the picture is modified only by 

 the extent of the process. Whether the ulcers are undermined or 

 not, there is always the same appearance of coagulative necrosis, 

 with l}Tnphoid infiltration, congestion, and thrombosis, and com- 

 paratively little polymorpho-leucocytic invasion. 



The two most evident features of the intestinal lesions, when 

 viewed with a comparatively low power of the microscope, are the 

 necrobiosis and the relative infrequence of leucocytes, features which 

 suggest the important role of the amoebae, for ordinarily in bacterial 

 infection there is an associated local leucocytosis of varying inten- 

 sity. A point of some importance is brought out by the fact that 

 in the very early lesions, the preulcerative ones, the amoebfe may 

 be encountered not merely in the glands but beneath the epithelium 



