THE DIGESTIVE SYSTEM. 525 



f reuulum may be abnormally short, or may extend to the tip of the tongue. In rare 

 cases the sides of the tongue are adherent, or its upper surface may be adherent to the 

 roof of the mouth. 



HYPERTROPHY AND INFLAMMATION. 



Macroglossia, or hypertrophy of the tongue, is. almost always a con- 

 genital lesion, and is especially common in cretins. The tongue may be 

 so large that it protrudes through the lips. The lips may also be simi- 

 larly enlarged. There is hyperplasia of the fibrous and other tissues of 

 the tongue, and in addition to this there may be a dilatation of the lym- 

 phatic vessels. 



Inflammations of the tongue may be associated with similar changes in 

 the niouth, or may occur by themselves. 



TUMORS. 



Cysts. The most common forms of cysts are the sacs beneath or partly 

 in the substance of the tongue ranula. They are formed by dilatation 

 of the ducts of the mucous glands, or of the submaxillary and subliugual 

 glands. Amyloid tumors of the tongue have been reported. ' 



Lipoma and fibroma are rare. They form nodules in the substance 

 of the tongue or project in a polypoid form. Composite tumors, com- 

 posed largely of fat, are found on the tongue as a congenital condition. 



Angioma. Cavernous vascular tumors are found in the substance of 

 the tongue and projecting from its surface. 



Sarcoma is not common in this situation, but may occur both in chil- 

 dren and in adults. Carcinoma, usually of the epitheliomatous type, may 

 originate in the tongue or may extend to it from the adjacent tissues. 



MICRO-ORGANISMS IN THE MOUTH. 



Micro-organisms of various forms bacteria, moulds, and yeasts are 

 always present in the mouth, often in enormous numbers. They are for 

 the most part not of significance save for the putrefactive processes 

 which they initiate and maintain in mouths not properly cleansed. On 

 the other hand, Staphylococcus and Streptococcus pyogeues and the piieu- 

 mococcus are of frequent occurrence in the mouths especially of those 

 who live in towns and crowded dwellings, and while usually harmless, 

 they may under favorable conditions become excitants of serious disease. 



The tubercle bacillus may be present in the mouth as well as in the 

 nose of those who care for uncleanly consumptives. 



The fungus of aphthae (soor), and leptothrix, which under usual 

 conditions are not harmful, may incite serious local disease. 



'See Schmidt, Virch. Arch., Bd. cxliii., p. 369, 1896, bibliography of amyloid 

 tumors in general. 



