508 



A MANUAL OF BACTERIOLOGY 



Balantidium (Paramecium) coli 



This is an intestinal parasite of swine, occasionally met with in 



man in conditions associated with chronic diarrhoea and dysentery. 

 It is somewhat ovoid in shape, the ends being bluntly pointed, is 

 covered with cilia, measures 65 to 85 /x in 

 length, and has a superficial resemblance 

 to the ordinary Paramecium. 



According to Saville Kent, the Balan- 

 tidium coli is to be distinguished from the 

 ordinary forms of water paramecia by the 

 following characters : The Bal. coli is some- 

 what spindle-shaped or ovoid, and bluntly 

 pointed at each end, one and a half to 

 twice as long as broad, measuring ^i^ in. 

 to T J-^ in. in length ; the paramecium is 

 more cylindrical, four times as long as 

 broad, measuring y l^ in. to T F in. in 

 length. The oral aperture in Bal. coli is 

 near one extremity (Fig. 57) ; in para- 

 mecium it is situated at about the middle 

 of the ventral surface. In Bal. coli the 

 cilia round the oral aperture are as long 

 again as those over the body generally ; in 



paramecium the whole of the cilia are of the same length. 



The Bal. coli seems undoubtedly sometimes to be a cause of 



dysentery. 1 Bal. coli is a common parasite of pigs and may 



contract infection from these animals. 



FIG. 57. Balantidium 

 coli. 



Examination of Flagellated and 

 Ciliated Forms 



(1) These may be examined fresh in the fluid in which they are 

 present, by mounting on a slide, and covering with a cover-glass 

 one edge of which rests on a bristle to avoid pressure. 



(2) Permanent mounts may be made by the Heidenhain method 

 (p. 485). 



(3) Films may be made in the ordinary way, and stained with 

 weak carbol-fuchsin or Leishman's stain. (The organisms are 

 apt to be distorted. ) 



(4) The following method, devised by Rousselet (Journ. Quekett 



1 Strong and Musgrave, Johns Hopkins Hosp. Ball., vol. xii, 1901, 

 p. 31 ; Bureau of Gov. Laboratories, Manila, Bull. 26, 1904. 



