STEUCTUEE AND MODE OF LIFE. 257 



Balantidium in two cases of typhus in the Dorpat Hospital, and 

 Ekeckrantz/ Belfrage,^ Windbladh,^ and Wising* soon reported four 

 more instances. The number of cases was afterwards doubled by 

 Petersson' and Henschen,^ so that apparently Balantidium does not 

 belong to the rarer human parasites. The Balantidia were always 

 found in individuals affected with more or less obstinate diarrhoea, 

 and once in association with numerous ulcers, especially of the caecum, 

 which finally led to the death of the patient (Belfrage's case). In one 

 case Henschen observed a complication with acute stomachic and 

 intestinal catarrh, but this was perhaps an exception. 



It is a striking fact that all the cases of Balantidium coli as yet 

 observed have been confined to a somewhat restricted geographical 

 area. No case of this kind has yet been observed in Germany, 

 England, or France,^ although the examination of the fteces has been 

 prosecuted at the universities in these countries as well as in Stock- 

 holm, Upsala, and Dorpat, and although the swine are probably, and 

 in Germany certainly, infested with these parasites. The reason of 

 this limited distribution in space can only be sought in local conditions. 

 There must be certain habits of life which determine the occurrence 

 of the parasite, but without more intimate knowledge of the circum- 

 stances we can hardly enter into details. Only this much is clear, 

 that the explanation is to be sought primarily in the relations between 

 men (especially in their food and drink) and the swine, which, in the 

 locaUties referred to, are probably fattened in the houses. 



Structure and Mode of Life. 



The ease with which we can procure specimens of Balantidium coli 

 from pigs has of course aided the progress of our knowledge of its 

 structure and life-history, so that this is at present, though not indeed 

 perfectly complete, at least satisfactory. 



The Body exhibits great permanency of form — greater at least 

 than we are wont to find in the naked Infusoria. This is specially 

 true of those specimens which are distended with food, and easily 

 detected by their compressed oval form and rounded posterior ex- 



' Loc cit. 



" " Fall af Balantidium ooli," Upsala lakareforen. Forliandl., Bd. v., p. 180. 



' "Fall af Balantidium coli," iUd., Bd. v., p. 619. 



* Loc. cit. 



° Upsala lakareforen Forhandl., Bd. viii., p. 251, 1873 (three cases). 



" " Fran Dr. Waidenstroms Poliklinik," ibid., Bd. iv., 591 (one case) ; and " Fern nya 

 Fall af Balantidium coli," ibid., Bd. x., p. 123 (five cases). 



' [Grassi states {loc. cit., p. 67) that Dr. Graziadi found Balantidium in one of the 

 ohlorctio patients at the St. Gotthard Tunnel ; and Treitte also reports it from Cochin- 

 Cbina {Archiv. mid., t. xL, p©;^'^g< &$77W/C!%sfe>i5f® 



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