508 THE ANIMAL PARASITES OF MAN 



berg; trichomonas elongata, Steinberg; trichomonas caudata, Steinberg; and 

 trichomonas flagellata, Steinberg, have been probably found as simple com- 

 mensals. 



Of the cilia inhabiting man, cilia infusoria, we are most interested in the 

 balantidium coli, Malmsten, 1857, the pathogenic significance of which as the 

 generator of severe dysenteric intestinal catarrhs is also described in the chap- 

 ter on Dysentery. Stockvis has also found balantidia in the sputum of a sol- 

 dier who had returned from the Sunda Islands. 



Jacoby and Schaudinn have recently found a new balantidium minutum 

 n. sp. in diarrheic stools, and also the nyctotherus faba n. sp., illustrations of 



Fig. 30. — Balantidium Minutum. Fig. 31. — Ntctothekus Faba. 



n, nucleus; cv, contractile vacuole. (After mi.n, micronucleus; ma.m, macronucleus. 



Schaudinn.) (After Schaudinn.) 



which follow. Vorticelli, which, according to Lindner, are said to infest man, 

 cannot yet be recognized as parasitic structures. 



This embraces the principal protozoa which occur in man. 



We now come to the more highly-organized class, the plathelminthes or 

 fiat-worins. To this group, which embraces the two classes of trematodes, or 

 sucking- worms, and cestodes, or tape- worms, belong the " vermes intestinalis " 

 of the earlier authors or " helminthes " which — sit venia verbo — represent the 

 true intestinal worms. 



TREMATODES 



The tongue- or leaf-shaped trematodes include the amphistomum hominis, 

 Lewis and McConnell, 1876. 



I wish to include this parasite for the sake of completeness. Observed 

 but a few times in the tropics, it possesses no actual interest for us, especially 

 since its significance as a parasite is by no means accurately determined. 



Of greater importance is the distomum hepaticum, Linne, 1758. 



The liver-fluke is found in the intestines and in the bile-ducts of a great 

 number of mammals, especially in the sheep. Eot or liver disease in many 

 districts creates great ravages among sheep. The parasite is also often noted 

 to occur sporadically. Its body is oblong, flat,' leaf -like, with a proboscidif orm 

 projjeetion on the cone-shaped head. One of the two suctorial discs is situ- 

 ated at the point of the cone-like head, and contains the opening of the mouth. 

 The other suctorial disc belongs to the abdominal surface. The oval eggs are 



