20 4 



THE ANIMAL PARASITES OF MAN 



believes that the ciliates are the primary etiologic factor in the 

 symptoms and lesions of balantidian dysentery. 



Behrenroth (1913) has given an interesting account of Balantidinm 

 coli and its pathogenic significance. 



Balantidium minutum, Schaudinn, 1899. 



The body is of oval form, with the anterior extremity pointed, and 

 posterior extremity broad and rounded (fig. 115). The length is 20 fju 

 to 32 yu,, and the breadth is 14 yu, to 20 //,. The peristome, which is 

 fissure-like, extends to the centre of the body (fig. 115). The right 

 lateral border of the peristome is beset with cilia the same length as 

 those of the body, the left side terminates in a thin hyaline membrane 



that extends towards the back, and can 

 pass over to the right side. A row of 

 longer and stronger cilia (cirri) are on the 

 left border of the peristome. The cuticle 

 is retractile, the ectoplasm hyaline and 

 the endoplasm granular, \vith numerous 

 food vacuoles. 



A single contractile vacuole lies dor- 

 sally and to one side at the posterior 

 extremity. The macronucleus, which is 

 always spherical, is central and is 6 //, to 

 7/x in diameter. The micronucleus, close 

 in front of it, only measures i //, (fig. 115). 



vacuole. Food vacuoles are repre- The Cysts are OVal. 



Scha'udinnO 116 cndoplasm ' These parasites were found in num- 



bers in the evacuations of a man aged 30, 



who was born in Germany and had repeatedly travelled between 

 Hamburg and North America, where he made long stays. The patient 

 came to the Charite in Berlin to seek advice for constipation alter- 

 nating with diarrhoea accompanied by abdominal pain. 



A second case (the parasite of which was described as Colpodtt 

 ci i cull us by Schulz) was observed in a patient in the same institution. 



As, in both cases, the parasites only appeared during the diarrhoea, 

 and disappeared as soon as the faeces had assumed a normal consis- 

 tency, or could only be demonstrated in a few encysted specimens, 

 it may be assumed that the small intestine or the duodenum is 

 their habitat. 



Genus. Nyctotherus, Leidy, 1849. 



Flat, heterotrichous Infusoria, kidney- or bean-shaped. The peristome com- 

 mences at the anterior pole of the body and extends along the concave side to the 



FIG. 115. Balantidium minu- 



