UNIVERSITY OF CALIFORNIA PUBLICATIONS 



IN 



ZOOLOGY 



Vol. 20, No. 18, pp. 401-408 October 31, 1923 



METHODS OF OBTAINING AMOEBA-FREE RATS 



FOR EXPERIMENTAL INFECTION WITH 



INTESTINAL AMOEBAE 



BY 



JOHN F. KESSEL 



CONTENTS 



PAGE 



A. Routine examination of nomial faeces 401 



B. Examination of faeces of rodents after administration of a purgative .... 403 



C. Incidence of infection at different ages 407 



B. Conclusions 408 



E. Literature cited 408 



In an investigation carried on recently by the writer an attempt 

 was made, first, to determine the different species of intestinal amoebae 

 found in culture rats and mice, and second, to establish, in culture 

 rats and mice, experimental infections of the common intestinal 

 amoebae of man and of the amoebae common to rats and mice. 

 During these experiments methods for hastening the evacuation of 

 the intestinal Protozoa in the faeces have been developed which it is 

 thought will prove of value to other investigators in similar fields. 



The writer is greatly indebted to Professor C. A. Kofoid of the 

 Department of Zoologj' in the University of California for suggestions 

 and guidance throughout the whole investigation of which this paper 

 records a part. 



A. ROUTINE EXAMINATION OF NORMAL FAECES 



Examination of human faecal material for the presence of intes- 

 tinal Protozoa has shown that it is necessary to examine samples taken 

 on several successive days in order to make accurate and complete 

 diagnosis of the organisms present. No experimental work has as 

 yet been done to determine the degree of certainty of the results of 

 such examinations of human faeces, but statistics show that the 



