26 THE COCCIDIIDEA. 



encysted, when we observe that their protoplasmic contents 

 separate away from the cell-wall and form a central round or 

 oval mass (/). Both adult and encysted stages may be freely 

 detected in the liver, in the white and yellow patches which are 

 characteristic of the disease. Now if we collect numbers of 

 these encysted forms and place them on damp sand in a warm 

 temperature, we shall soon observe by microscopic examination 

 that the central protoplasmic ball splits into two and then four 

 {g and h). This is a kind of segmentation or division, the 

 round bodies being known as "sporoblasts." These sporoblasts 

 elongate, expand at each end, and are seen to be surrounded 

 by a thin membrane, within which is also seen a granular lump. 

 Each of these "sporoblasts" really contains two spores, the 

 falciform spores (o), described in a typical sporozoon — in fact, 

 the so-called sporoblast is a pseudo-navicella. Each falciform 

 body gives rise to a little flagelloid creature. This form migrates 

 from cell to cell of the animal's liver, encysting and producing 

 more spores, and so rapidly increasing the area of the disease. 

 It is supposed that these sporiferous cysts are carried with 

 dust, &c., and hence get taken into the mouth with food, 

 eventually reaching the liver. The sporocyst ruptures through 

 the action of the pancreatic juice, the gastric juice having no 

 effect upon them, and the sporoblasts appear ; these latter 

 burst and discharge the spores or falciform bodies, which 

 become active, and are said to ascend by the ductus chole- 

 doohus to the epithelium of the liver and bile-duct. Here the 

 germs, having entered some of the hepatic cells, cause these cells 

 to rupture, and they may even destroy the walls of the bile-duct 

 itself. They finally encyst, pass out into the intestine, freed by 

 the breaking up of the tissues in which they are embedded, and 

 so out to ground by the anus of the diseased animal. 



Their presence causes the liver to swell. They are detected 

 by the creamy cystic areas, varying in size from a millet-seed to 

 that of a pea. They are often so abundant that the cells of the 

 liver atrophy, and cheesy-like masses appear not only in the 



