830 



THE INFUSORIA 



Balantidium coli. 



(Paramoecium coli.) 



This protozoon is found in the intestines and stools of man and pigs : it 

 was first described by Malmsten but it appears to have been previously seen 

 by Leeuwenhoek in the excreta. 



It would seem to have been proved that Balantidium coli may produce 

 disease : it has been found in numerous cases of catarrhal colitis and ulcera- 

 tive dysentery in man in America, the Philippines, Finland, Bothnia, Russia, 

 Germany, etc. (Russell, Losch, Strong and Musgrave, and others). 



FIG. 403. Balantidium coli. 



FIG. 404. Balantidium coli in stools. (After Guiart.) 



Askanazy, and Klimenko have shown that not only is Balantidium coli 

 found in extraordinarily large numbers in ulcerative lesions of the intestine 

 but that it finds its way into the deep layers of the colon, into healthy 

 tissues and even into small blood and lymph vessels : this power of penetra- 

 tion explains the finding of the parasite by Manson and Stockvis in liver 

 abscesses. [Brooks attributed a fatal epizootic of dysentery among the orang- 

 outangs in the zoological gardens at New York to this parasite.] 



It is necessary, however, to point out that up till now it has not been 

 possible to produce experimentally in man or in monkeys an ulcerative 

 colitis with Balantidium coli. Grassi and Calandruccio failed to infect 

 themselves by swallowing cysts of Balantidium coli obtained from a pig. 



Morphology .Balantidium coli is an oval-shaped organism measuring 

 from 70-100/x long which can be seen with the unaided eye : its surface is 

 covered with short, delicate vibratile cilia arranged in regular longitudinal 

 lines. 



At the narrower end of the body there is a mouth or cytostome destined to 

 receive the food, and at the larger end a second orifice or cytopyge for the 

 removal of the waste products of digestion. Around the mouth the cilia 

 are grouped in a -ring or collar and move in such a way as to direct food 

 material towards the mouth. The arrangement of the "nucleus is charac- 

 teristic : the macronucleus has the shape of an haricot bean in the concavity 

 of which the rounded micronucleus is situated. The protoplasm contains 

 two or three contractile vacuoles in which ingested materials of external 

 origin such as blood cells, starch granules, fat droplets, etc. are frequently 

 found. 



The cysts are spherical (vide ante) and measure 80-100/x across. They 

 are found in cold and dried excreta. 



