1924] 



Kessel: Amoebae of Culture Rats and Mice 



49^ 



COUNCILMANIA MURIS (Grassi, 1881), emend. Kessel 



Occurrence. — Councilmania muris has been found in 14 of the 25 

 rats and in 4 of the 17 mice from which stained slides of the faecal 

 material have been prepared in this laboratory (see table 4). An exam- 

 ination of the stained slides has been our main and most conclusive 

 method of differentiating this species from Councilmania decumani; 

 the positive cases diagnosed in fresh smears only have not been con- 

 sidered in the percentages cited above. 



TABLE 3 



Table Showing Incidenck of Amoebic Infection in Eats and Mice 

 Eecorded in Literature 



Investigator 



Wenyon 



Brug 



Rudovsky . 

 Rudovsky 



Balfour 



Balfour 



Kessel 



Kessel 



Kessel 



Species of Animal 



Mus musculus 



Mus rattus 



Mus musculus 



Mus musculus 



Black rats 



Brown rats 



Mus norvegicus 



Mus musculus (albino) 

 Mus musculus (wild) ,, 



Positive 



Negati^ 



Total 



Per cent 

 positive 



Not stated 



7 







5 

 Not stated 

 Not stated 



96 

 30 



2 



Not stated 

 43 

 37 

 1.59 



Not stated 



Not stated 



172 



00 



21 



Not stated 



50 



37 

 164 



34 

 444 

 268 



80 



23 



50.0% 

 14.0% 



0.0% 



3.0% 

 25.0% 

 15.7% 



3.6% 

 37.5% 



9.0% 



The Motile Amoeba 



Habitat. — The normal habitat of this amoeba is the caecum. I^nless 

 examination is made following a purgative, the motile forms are sel- 

 dom found in the colon at autopsy. Just how the active amoebae are 

 restricted in habitat almost entirely to the caecum, while the contents 

 of the caecum within which the amoebae have been mixed are dis- 

 charged into the colon, affords an interesting problem. According to 

 Cannon and McNease (1923) the pH of the caecal contents is more 



