19-1] Kofoid-Swczy: Councilmania la/tcuri 181 



BUDDING AND ESCAPE OP AMOEBULAE 

 Plates 20-22, figures 15 to 28 



The genus CouiicUmcniia appears to differ from all other intestinal 

 amoebae of man in the occurrence in fresh stools, and therefore pre- 

 sumably also in the lower level, of a reproductive process of repeated 

 budding resulting in the escape of amoebulae from the cyst. Such a 

 process has not been observed by us in the encysted stages of Enda- 

 mocba dyscntcnae, E. coli, or in Endolimax nana. We find no record 

 of such a process in the cysts of any parasitic intestinal amoeba other 

 than Councilmania, except possibly in Endamoeha muris as described 

 by Wenyon (1907), but otherwise interpreted by him. 



We have designated the process as one of budding since it may be 

 preceded by the formation of a ridge or intracystie process which 

 resiilts in a protrusion of protoplasm through a small opening in the 

 cyst wall, in the escape of a nucleus into this lobe, and in the subse- 

 quent detachment of an amoebula, to be followed by a repetition of the 

 process until the cyst is emptied of all its nuclei. 



The evidence upon which this conclusion rests is given in some 

 detail since Dobell (1920) rejects as "an incorrect and arbitrary series 

 of stages" the account of Mathis and Mercier (1917), who described 

 the emergence of amoebulae from the cysts of an amoeba which they 

 called E. coli, but which is undoubtedly Councilmania. Dobell is cor- 

 rect, it seems to us, in denying the existence of these phenomena in 

 E. coli, but not in discrediting the observations of these investigators. 

 Their observations were correct as far as they went, but they apply to 

 Councilmania YaX\\ev than E. coli. We agree with Dobell in not ac- 

 cepting their interpretation of a gamogenic-schizogamic cycle in E. coli, 

 and find no evidence for such a double cycle in Councilmania. 



The intracystie ridge which precedes and attends the early phases 

 of the fonnation of the bud first appears as a chromophile, deeply 

 staining tract which becomes an elevated ridge or keel of varying 

 width which may run halfway round the cyst, or even fai'ther, within 

 the wall. It may be a narrow dark thread (pi. 21, fig. 19), or a blunt 

 process (pi. 21, fig. 17), or a broader ridge (fig. 21). It is generally 

 direct in its course, but is sometimes bifurcated at one end (pi. 21, 

 fig. 19). In optical section it forms a distinct, elevated ridge on the 

 contour of the cytoplasm within the cyst wall. 



