THE DIGESTIVE SYSTEM. 523 



clear vesicles may form beneath the epithelium from the collection of 

 serous exudate. 



Croupous Stomatitis is incited by local irritants, by local infection, or 

 by the extension of the same form of inflammation from the pharynx ; it 

 frequently occurs with diphtheria and other infectious diseases. 



Portions of the mucous membrane are swollen and congested, and 

 covered with a false membrane. This false membrane is composed of a 

 thickened layer of epithelium in the condition of coagulation necrosis, 

 and of fibrin and pus in variable relative quantity. The stroma of the 

 mucous membrane may be infiltrated with pus and fibrin, and portions 

 of it may become necrotic. 



Aphthous Stomatitis. In this condition small whitish projecting 

 patches surrounded by a zone of hypersemia may form upon the mucous 

 membrane. These consist of a more or less fibrinous exudate beneath 

 the epithelium which may exfoliate, leaving small ulcers. 



Ulcerative Stomatitis. This form of stomatitis is apt to occur in ill- 

 nourished children or in young adults, in scurvy, or in mercurial poison- 

 ing. It usually begins at the margin of the gums of the lower jaw and 

 extends to the cheeks and tongue. The affected parts are swollen and 

 coated with a grayish, soft pellicle composed of bacteria and necrotic tis- 

 sue. The gums may be destroyed around the teeth, and these may fall 

 out. The surrounding soft parts are swollen, and there may be necrosis 

 of the jaws. 



In Noma or Gangrenous Stomatitis similar changes may be associated 

 with extensive gangrenous destruction of the cheeks. This most often 

 occurs in young children in connection with measles, scarlatina, or ty- 

 phoid fever. It has been claimed that a special micro-organism is the 

 excitant of this disease, but this has not yet been proven. 



Thrush. (Soor; Parasitic Stomatitis.) In ill -nourished children or in 

 adults suffering from chronic disease a fungus related to the yeasts 

 oidium albicans may grow among the epithelial cells of the mouth, form- 

 ing white membranous patches. These may involve large areas of the 

 mouth and pharynx and may extend to the esophagus or upper respira- 

 tory passages. 



Phlegmonous Stomatitis. Exudative inflammation of the mouth may 

 result from infected wounds, in connection with erysipelas or suppura- 

 tive or other infectious process near the mouth. Various pyogenic bac- 

 teria may be its excitants. 



Chronic Stomatitis. This may follow acute catarrhal or other inflam- 

 matory processes, and may be due to persistent irritation, for example, 

 from the use of tobacco. Owing to hyperplasia of the epithelium and 

 submucous tissue white patches of varying extent may form on the 

 tongue or elsewhere leucoplakia buccalis. These through excessive in- 

 crease in the epithelium may project in wart-like form from the surface 

 ichthyosis. 



Tuberculous Stomatitis commences with the formation of miliary 

 tubercles or of larger tuberculous masses in the stroma of the mucous 



