AMCEBA COLI 31 



acid reaction the intestinal amoebae die off ; a low temperature 

 retards the amoeboid movement, and finally causes it to cease. 

 The number of vacuoles varies ; they rarely change form. A 

 nucleus is always present, though it cannot always be seen in the 

 living animal ; after death, or through the addition of reagents 

 (acetic acid, sublimate), it shows clearly ; its form is spherical, 



FIG. i. Amoeba coli, Loesch, in the intestinal mucus, containing blood and pus 

 corpuscles. (After Loesch.) 



and it is of the same size as the vacuoles (0-006 mm.). 

 According to some authors the nucleolus is easily detected, others 

 state that it is only exceptionally visible. 



The propagation of the amoeba takes place in the intestine by 

 simple division (it has been observed by Casagrandi and Barbagallo 1 

 as well as by Harris 2 ). The transmission to other hosts is appar- 



FIG. 2. Encysted intestinal amceba in the act of propagation. (After B. Grassi.) 



ently effected exclusively by encysted forms, the protoplasm of 

 which, after repeated division of the nucleus, separates itself 

 into as many parts as there are new nuclei (Casagrandi and 

 Barbagallo), by arranging itself round each new nucleus. According 



'Casagrandi, O., and Barbagallo, P., " SulV amoeba coli" (Boll. Accad. Gioenea, 

 sc. nat. Catania, 1895). 



a Harris, H. F., "Some Observations on a Method of Multiplication of the Amceba 

 dysenteries" (Med. News, 1894, Ixv., No. 21, p. 567). 



