UNIVERSITY OF CALIFORNIA PUBLICATIONS 



IN 



ZOOLOGY 



Vol. 20, No. 7, pp. 169-198, plates 18-22, 3 figures in text June 23, 1921 



ON THE FREE, ENCYSTED, AND BUD 

 STAGES OF COUNCILMANIA LAFLE 

 A PARASITIC AMOEBA OF TH 

 HUMAN INTESTINE* 



BY 



CHARLES ATWOOD KOFOID and OLIVE SWEZY 



CONTENTS PAGE 



Introduction 169 



Material and methods 171 



Activities ._. 171 



The free amoeba 173 



The encysted phases _ 175 



Dimensions _ 180 



Budding and escape of anioebulae 181 



Occurrence 183 



Culture and inoculation 185 



Viability of cysts 185 



Distinctions between Councilmania lafleuri and Endamoeha coli 186 



Summary _ 187 



Literature cited 188 



INTRODUCTION 



The perplexing confusion which has long existed regarding the 

 amoebae of the human digestive tract owes its origin and growth to a 

 complex of causes, including the difficulties of securing and controlling 

 fresh normal material, the existence of pathological, moribund, and 

 abnormal stages in the parasitic organisms themselves, and the presence 

 in man of miiltiple infections of molds, yeasts, flagellates, coccidia, and 

 amoebae, with diverse races and phases in their life histories. The 

 clinician and protozoologist must learn to distinguish these several 

 organisms in their various aspects and avoid confusing them if therapy 

 is to be critically applied, and morphology and life history are to be 

 correctly interpreted. 



* From the Zoological Laboratory, University of California, and the Division 

 of Parasitology, Bureau of Communicable Diseases, California State Board of 

 Health. 



