130 AMEB.E 



Possibly Endamaha coli will prove to be a group of related species 

 instead of a single species. In Brazil, for instance, Aragao has 

 described an ameba very similar to E. coli in some respects, but 

 with certain constant differences, which he named E. brazilien- 

 sis. A small ameba, Vahlkampjia lobospinosa (Fig. 36), usually 

 supposed to be identical with the free-living fresh water species, is 

 often found in the large intestine and in faeces, probably having been 



ingested in cyst form with food. It does no 

 .(^y damage whatever. In our mouths several 

 species find a congenial environment, and 

 one, E. gingivalis (buccalis), is very common 

 and is thought by most workers to be at 

 least indirectly connected with pyorrhea, 

 which, next to decaying teeth, is probably 



Fig. .36. Vahlkampfia .■, , , ,- j~, . . ,. 



iobo8pi,wsa (whitmorei). ^^c Commonest human disease. E. gingivalis 

 c. v., contractile vacu- also attacks the tonsils, and is probably 



olc; n., nucleus. X 1-300. • v ,1 ,i c - • 1 • j r -j. 



(.\fter Whitmore.) mdu'ectly the cause ot certam kinds ot goitre. 



Another species of ameba, which has only 

 rarel}' been found, is E. 7nortinatalium. It has been observed in 

 various organs such as the liver, kidneys and lungs of syphilitic 

 infants and in two cases in the parotid glands of non-syphilitic 

 infants. Syphilis seems to serve as a favoring circumstance for 

 this species. On account of its rarity this ameba is not of such 

 importance to the human race as E. histolytica or E. gingivalis, 

 though apparent]}^ very destructive when it does occur. Another 

 species, E. urogenitalis, has occasionally been found in the urogenital 

 tract, being voided with the urine. Two species of Craigia live 

 as intestinal parasites of man, and cause a type of dysentery 

 closely resembling that caused by E. histolytica. 



Amebic Dysentery 



Importance. — One of the most serious menaces in the tropics 

 is dysentery; people who have always lived in temperate countries 

 have no conception of the .scverit}^ of this ailment. In many 

 tropical countries dysen ery ranks next only to malaria as a cause 

 of death, and very often it finishes the work of such diseases as 

 malaria, kala azar, and other fevers. When the American troops 

 occupied Vera Cruz in 1914 they found dysentery one of the chief 

 causes of death among the Mexican population. The occu- 



