210 COCCIDIUM OVIFORME. 



spot (0'005 mm.), which enclosed nucleoli, and was easily distinguished 

 from the cell-contents, though destitute of a special membrane. The 

 form of the enclosing cells varied very markedly, the transverse 

 diameter having grown to double the former size. This change was, 

 of course, still more striking afterwards, for the germ inside continues 

 growing till it finally becomes a spherical ball of about O026 mm. In 

 this state the parasite has, apart from the absence of the cuticle, an un- 

 deniable resemblance to a Gregarine. Its protoplasm is granular, but 

 always allows the nucleus to be seen glimmering through as a clear 

 spot. It now fills the cell so completely that the latter is seen only 

 as a narrow limiting envelope. I have usually been able to find the 

 original nucleus only in the earlier stages of the parasites. 



The number of germs which find their way in is usually so con- 

 siderable that the cells are generally wholly infected with parasites of 

 different sizes and stages. It is by no means always a single germ 

 which invades each cell, two are sometimes found together, and 

 occasionally the number is still larger. I have found cells in which I 

 could distinguish five or six granular masses of unequal size lying 

 together. 1 



As soon as the granular masses have attained their maximum size, 

 the transformation into the true Coccidium-ioim begins. The ball, 

 which has still retained its round form, assumes a more oval shape, 

 and surrounds itself under the previous enve- 

 lope with a rapidly thickening shell. As long as 

 the cell-wall persists, the Coccidia lie in or on 

 the walls of the liver-nodules, but later, as we 

 have seen, they are found in the inner space, 

 embedded in a finely granular detritus, with 

 nuclei, remains of cells, and shed epithelial 

 elements. 



FIG. no. Adult Coccidia "VVe have already described (p. 206) how 

 these Coccidia (Fig. 110) change during their 



stay in the liver. We know that the definitive shell, with its micropyle 

 and double contour, subsequently appears under the original primordial 

 coat, 2 and that the granular protoplasm within rolls itself up into a ball 

 in the middle of the capsule. 



1 Waldenburg and Rivolta account for several germs within one cell (seen also by 

 Klebs, Reincke, and Neumann), not by a repeated immigration, but by a division of the 

 original occupant. 



2 I may here expressly note that this assertion rests on no confusion with the 

 remains of the cells which lie immediately round the Coccidia, for the casting of the skin 

 can sometimes still be observed in specimens which have been kept for some time in water. 

 On the other hand, the representations which Lieberkiihn makes of Coccidia with double 

 walls obviously refer (since sometimes two or three Coccidia are lying within the same 

 envelope) to specimens still within their epithelial cells ("Evolution des Grdgarines," 

 loc. cit., p. 33). 



