Intestinal Parasites in Swine. 293 



When dropped in water they move freely at first, but soon be- 

 come motionless, loose their cilia (first the short, then the oral), 

 and contract into spherical bodies. In this condition, as well as 

 when dried in the fseces, they are very tenacious of life, and find 

 their way into the alimentary canal of a fresh host through the 

 food and water. 



Pathogenesis. They have not been observed to prove hurtful 

 to swine, but in man they cause severe indigestion and profuse 

 and obstinate diarrhoea. Wising finds the parasite much smaller 

 in man, while Calandruccio and Grassi failed to produce the dis- 

 ease in man by feeding the parasite of the pig. Unless the two 

 are specifically distinct the protection of man would require their 

 destruction in swine. 



Trichomonas Intestinalis. lyike other trichomonas this in- 

 fusorian has four or five anterior flagella, one of which is directed 

 backward and projects beyond the caudal end of the body. It 

 has been found by Kunstler in the intestine of swine, but appears 

 to be much more common in man. liio pathogenesis has been ob- 

 served. 



CESTODES. 



No adult cestode is known to infest the intestine of swine. The 

 taenia solium which exists in the human subject in both the ma- 

 ture and larval forms is found only in the latter form as the cysti- 

 cercus cellulosa in the muscles and connective tissue of the pig. 

 Tardieu claims that he saw portions of a taenia passed by a pig, 

 but no such occurrence has been noted by any other observer. 



TREMATODSS. 



Distoma hepaticum and distoma lanceolatum both live in the 

 gall ducts of swine, and will exceptionally escape into the small 

 intestine and be found there. The ova must pass through the 

 bowel to reach their succeeding stage of development in fresh 

 water. 



ACANTHOCEPHALA. 



Echinorhynchus gigas. This is a cylindroid worm some- 

 times slightly thickened at intervals and always greatly attenuated 

 toward its caudal end. The anterior extremity bears a protrac- 

 tile proboscis, globular or conoid, and covered by a large nunjber 



