PARASITIC DISEASES OF THE LIVER. 



307 



" flock ^'), and essentially constituted by protoplasm containing a 

 niwleus, the whole destined to become encysted. 



According to Leuckart, the term psorosperms is incorrect as a 

 denomination for these organisms, which belong to the group of 

 sporozoa; this appellation is indeed extended to the entire mother 

 gregarina, inside of which the so-called psorosperms — that is to say, 

 the spores — are only developed later. Leuckart designates the 

 sporozoa in question under the name of coccidia. We recognize 

 one principal species, the Coccidium oviformCy which inhabits the 

 liver, and a secondary species, Coccidium perforans, which lives in 

 the intestine. 



These coccidia represent (according to Leuckart), in their young 

 age, parasites without covering except the epithelial cells of the 

 biliary canals and intestine ; having arrived at the adult age, these 

 worms become surrounded with a solid shell ; they then leave the 

 inside of their host, reaching the open air, and if deposited in a damp 

 and dark place (stables, barns, etc.), they are slowly developed. 

 Their globular contents are transformed into four spores of oval 

 shape, each representing a small stick of hyaline, having the shape 

 of a C, the concavity of each little stick containing a remnant of 

 the granular mass of the spore ; the four elements (falciform cor- 

 puscles) fill the inside of the coccidium.^ In the stomach of a new 

 host, into which they enter with the food, they become free, each 

 little stick being transformed into a naked amœboid cell of the size 

 of a white blood-corpuscle, which penetrates, either into the intes- 

 tinal epithelium (Coccidium perforans), or into the hepatic epithe- 

 lium through the biliary canals (Coccidium oviforme). Once inside 

 of the epithelial cell, the gregarina is surrounded by a cuticle and 

 increases to double its primitive size ; it is then oviform, with a 

 microscopic opening at its pointed extremity, which renders it 

 similar to the eggs of some entozoa, with which, indeed, it has 

 been confounded. 



Pathological anatomy. In coccidiosis of the rabbit the liver 

 is more or less increased in volume; sometimes it is bosselated 

 upon its surface. Its parenchyma is filled with white-yellowish 

 cysts, of the size of a millet seed, of a bean, or of a hazel-nut, and 

 which are sometimes found in such numbers that the interposed 

 hepatic tissue is found to be completely hypertrophied. These cysts, 



1 According to Balbiani, each of these four falciform corpuscles is in reality com- 

 posed of two associated corpuscles, disposed tête-bêche.— s . d. t. 



