Kessel: Infection with Intestinal Amoebae 



403 



be inadequate in making a diagnosis for rats and mice. It is further 

 seen that the number of examinations necessary to determine the 

 exact infections present, or to make it relatively certain that an 

 animal is free from a given infection, would extend over an almo.st 

 prohibitive period of time in experimental work. It was therefore 

 decided to evacuate the amoebae in the faeces through administration 

 of a purgative. 



TABLE 1 



Results of Eoutine Examination of Normal Rodent Faeces for 

 Intestinal Amoebae 



B. EXAMINATION OF FAECES OF RODENTS AFTER 

 ADMINISTRATION OF A PURGATIVE 



Castor oil mixed with food was first tried as a purgative. The 

 faeces were evacuated successfully, but the oil droplets in the smear 

 were confusing because of their resemblance, in optical properties, to 

 amoebic cysts, especially when seen through a low power microscope. 

 So commercial epsom salt was used instead. At first this was mixed 

 with the drinking water and given to the rats in their water bottles. 

 As the animals refrained from drinking the mixture, except when 

 especially thirsty, the salt was mixed with food. 



