142 AMEB^E 



Endamoeba gingivalis and Disease. As intimated above, 

 although the presence of amebse in the mouth has been known 

 for many years, these parasites attracted little interest until 

 1914 when several investigators called attention to an apparent 

 relationship between the amebse and the presence of pus pockets 

 between the teeth and gums, a disease known to dentists and 

 physicians as " pyorrhea alveolaris." The amebse do not thrive 

 on exposed surfaces in the mouth, but find a congenial environ- 

 ment in any little secluded pockets between the teeth and gums, 

 in crevices between close-fitting teeth, or where a bit of food forms 

 a protected spot for them. Stowed away 

 in such places, and invariably accompanied 

 by bacteria and often spirochsetes, they 

 multiply rapidly. That they feed largely 

 on other organisms cannot be doubted, but 

 that they prey also on the living tissue 

 cells is practically certain. Eventually the 

 delicate peridental membrane surrounding 

 the roots of the teeth (Fig. 42), correspond- 

 ing in a general way to the periosteum of 

 bones, is eaten away and becomes ulcerated. 



FIG. 42. Sketch of _. ,. ,. ,, ,. . , 



tooth showing peridental The eating away of the living membranes 

 membrane, which is the o f the teeth and gums is accompanied by 



tissue attacked by Enda- Jf ,. P , , , 



mceba gingivalis and the a constant formation ot pus, and a marked 



seat of pyorrhea, peri- proneness for the gums to bleed, often with- 



dent., peridental mem- ,. ,,, n j u 



brane; periost., perios- out provocation. The swallowing and ab- 

 teum; cr., crown; r., SO rption of the pus and of the poisonous 



root; p. pulp. (After . , , .. ' 



Bass and Johns.) waste products generated by the parasitic 



organisms are probably the cause of the 



more or less noticeable constitutional symptoms which accom- 

 pany the disease. These may consist of feverishness, dis- 

 ordered digestion, nervous troubles, rheumatic pains in the 

 joints, anemia, or various combinations of these ailments. We 

 have long known that unhealthy mouths were the cause of gen- 

 eral bad health, but we never until recently had any definite clue 

 to the reason why. 



As the ulceration of the membrane continues, the tooth is 

 gradually loosened from the gum. Just as meadow mice girdle 

 fruit trees, so these amebae, or the bacteria or spirochsetes which 

 accompany them, eat away the living " bark " of the teeth and 



