(Part 2 of 2) ----------------------------------------------------------------- ENCYSTED STAGE -----------+---------------------------+------------------------- | Endolimax nana | Iodamoeba bütschlii -----------+---------------------------+------------------------- Size | 7-9µ | 9-12µ -----------+---------------------------+------------------------- Shape | Usually oval. | More or less rounded. -----------+---------------------------+------------------------- Wall | Thin. | Relatively thick. | | -----------+---------------------------+------------------------- Nuclei |Very small. May show from |One relatively larger |one to four nuclei. Rarely |nucleus. Differs struct- |eight. Structurally similar|urally from the adult |to adult type of nucleus. |type in that the granules | |in the clear zone become | |massed at one pole giving | |an eccentric karyosome. -----------+---------------------------+------------------------- Chromatoids|Absent. |Absent. | | -----------+---------------------------+------------------------- Glycogen |Rarely present. |Dense glycogen mass is | |characteristic. | | -----------+---------------------------+------------------------- Walker also notes the advantages of examining a specimen with a ⅔ inch objective as encysted amoebae are easily picked up. In opposition to the usual recommendation of text-books to report only on motile amoebae, he recommends the making of a differential diagnosis on nonmotile encysted forms. This however is now generally accepted by experienced workers as true. The preëncysted _E. histolytica_ has a nucleus much resembling that of _E. coli_. The presence of the same chromidial bodies one notes in the cysts is an aid in recognizing this stage. The 4 nuclei of the cysts are much smaller than the nucleus of the preëncysted or vegetative stage. PROPHYLAXIS AND TREATMENT =Prophylaxis.=—The main consideration is a knowledge of the importance of the carrier problem. The stools of all persons preparing food in localities where amoebic dysentery is prevalent should therefore be examined for the 4-nucleated cyst of the pathogenic amoeba. It must be remembered that while emetine controls the dysenteric manifestations of amoebiasis it does not seem to cause the disappearance of the parasite, so that patients who have had amoebic dysentery tend to become carriers.