1921] Kofoid-Swczy: Councilmania lafleuri 171 



MATERIAL AND METHODS 



The material upon which this study is based is derived from ten 

 eases under observation for varying periods from July, 1920, to June, 

 1921. One case especially has been examined almost daily for over 

 120 days, the infection appearing, prior to treatment, in nearly every 

 stool examined from this and some of the other cases under observation. 

 Hundreds of fresh smears and over nine hundred prepared slides of 

 both stained smears and sections have been available for study, as have 

 also several warm stools with an abundance of free amoebae. 



Our attention was fir!5t drawn to the species by its remarkable 

 resistance to stain in the usual Schaudinn-iron haematoxylin treatment, 

 the cysts remaining quite colorless while those of other intestinal 

 amoebae were stained as usual. It was only after fixing in Schaudinn 's 

 fluid at 60° C. for several minutes that we were able to stain the cysts 

 in iron haematoxylin. 



"We have been able to observe the living organism in the electric 

 incubator and to secure preparations of all stages from the free amoeba 

 to the eight-nucleated cj'st and the escaping amoebulae, and are thus 

 able to determine its distinctive characteristics. 



We are deeply indebted to physicians and patients who have made 

 this investigation possible, especially to Dr. C. L. McVey, of the staff 

 of the University Infirmary, and to Dr. R. T. Legge, University 

 Physician, and to students in their charge who have generously co- 

 operated to make our observations possible. Acknowledgments are 

 gratefully made for grants from Mrs. Margaret B. Fowler and an 

 alumnus of the class of 1900 in support of this work. 



ACTIVITIES 



In warm liquid stools following a purge of magnesium sulphate, 

 examined on the warm stage or electric incubator, the free amoebae 

 predominate and are many of them very active. Some are rounded 

 up and inactive and among them are probably precystic stages dis- 

 charged prior to the early phases of encystment. 



Amoebae in the active stages creep about with great rapidity. One 

 elongated amoeba traversed five times its length in one minute and 



