334 Veterinary Medicine. 



also been observed in man (Gubler, Dressier, Virchow, Leuck- 

 art), and, it has been supposed, in swine, though the ovoid or- 

 ganisms found by Johne in the pig's liver were three times the 

 size of the specimens found in the rabbit or in man. 



The parasite belongs to the order Protozoa and class of Spor- 

 ozoa, and is known as the Coccidium Oviforme. It is an ovoid 

 body, flattened at the ends, and consisting of protoplasmic con- 

 tents, surrounded in the mature condition by a membraneous sac 

 constructed in two layers and entirely devoid of cilia, flagella or 

 suckers. As found in the rabbit it is 30/«. to 40 /t long by 16 ju. to 

 23 ju. broad. Johne's specimens found in the pig were 120 ;«. by 

 70 /*. The parasite is propagated by .spores, formed in the interior 

 of the parent organism and set free by the rupture of the cyst. 

 Before the liberation of the spore it is transformed into a falci- 

 form body with amoeboid movements in the interior of the epithe- 

 lium of the biliary duct, by which it is enabled to ascend the bile 

 ducts from the intestine, and to enter the biliary epithelium. 

 Balbiani has cultivated the sporocyst in water and moist sand, and 

 found that the protoplasmic contents, which often contract to a 

 globular form within the cyst, will undergo segmentation in two 

 or three days, and that in ten or fifteen days, in summer, the 

 complete evolution will be effected. Segmentation takes place 

 first in two, then four rounded sporobla.sts, then each becomes 

 elongated, bends over or swells into a rounded ball at each end, 

 between which the remnant of the protoplasmic spore can be seen. 

 This elongated body next divides longitudinally into two, so as 

 to leave one rounded knob at one end of each, and the resulting 

 falciform body shows amoeboid movements and becomes the 

 embryo sporozoon. When evolution takes place in water or 

 damp mud outside the animal body, the spore-bearing cysts ap- 

 pear to be dried up and carried in the flying dust to be deposited 

 on the food of the rabbit. When introduced into the alimentary 

 canal the cyst is ruptured, and the freed spores in turn liberate 

 the falciform bodies which penetrate the biliary ducts and epithe- 

 lial cells by virtue of their amoeboid movements. The invaded 

 epithelial cell swells out into an ovoid form, which remains for 

 a time adherent by a pedicle, but finally drops off, and they ac- 

 cumulate in grumous or cheesy masses in the dilated biliary ducts. 

 Microscopic examination reveals the real nature of these deposits. 



