MORBID ANATOMY 



177 



circular, slightly projecting 

 masses, stained yellowish or 

 blackish or both in alternate 

 rings, or they may be slighth' 

 depressed and somewhat ragged 

 in outline. When the superficial 

 slough is scraped away many ul- 

 cers show a grayish or white base. 

 A vertical section reveals a 

 rather firm neoplastic growth, 

 extending usually to the inner 

 nuiscularcoat. When sections of 

 such an ulcer are stained with 

 aniline dyes and examined under 

 the microscope, the submucous 

 tissue is very much thickened, 

 infiltrated with round cells and 

 containing a large number of di- 

 lated vessels. Resting upon this 

 thickened subnuicosa, is a line of 

 very deeply stained amorphous 

 matter and upon this is situated 

 the necrotic mass which fails to 

 retain the coloring matter and 

 which is permeated by an im- 

 mense number of bacteria of vari- 

 ous kinds. Frequently the eggs 

 of trichocephalus are imbedded 

 in the slough. 



Spleens of pigs of 

 [a] dead from hog 



Fig. 41. 

 The extent of the submu- the same age 



cous infiltration depends upon cholera; [b) normal, {killed iti 

 the age of the ulcer. In old ^"'<'^^^n- 



ulcers it contains many newdy-formed capillaries and evidences 

 of the formation of connective tissue are present. The capil- 

 laries may extend to the very edge of the border where the 

 slough begins. The latter may have been partly shed, leaving a 

 smooth line bounding the cicatricial tissue. The submucous in- 

 filtration gradually disappears toward the periphery of the ulcer 



