1922] on Microscopic Parasites and their Carriers 



505 



Pig. 1. — The Intestinal Amoeba of Man, which are carried from man 

 to man by cysts voided in the f.eces. (magnified 1250 times.) 

 a-c Entamoeba histolytica, the cause of amoebic dysentery. 

 A, the tissue-invading form with one nucleus and six ingested red blood 

 corpuscles ; b, the small form (precystic form), which will protect itself 

 by a cyst ; c, the cyst containing the amoeba, with four nuclei and 

 chromatoid bodies. 



d-f Entamoeba coli, the large non-pathogenic amoeba of man, which lives 

 in the lumen and on the surface of the intestine. 

 D, the large multiplying form with one nucleus and various ingested food bodies ; 

 e, the small precystic form, which will become encysted ; f, the cyst con- 

 taining the amoeba with eight nuclei. 



g-i Ioclamceba butschlii, another harmless amoeba of man. 

 G, the active form ; h, the small precystic form, which will encyst ; I, the 

 cyst with a single nucleus and vacuole, which contains a substance 

 (glycogen) which stains brown with iodine. 



j-l Enclolimax nana, a small harmless amoeba of man. 

 J, the active form; k, the precystic form; l, the cyst with four nuclei. 



m-n Dientamceba fragilis, another small harmless amoeba of man, of which the 

 encysted form has not yet been discovered. It frequently has two nuclei. 



