THE NEOSPOREDIA 



413 



ticular of its nucleus, which becomes of gigantic size, and multiplies 

 by division, usually in a direct and irregular manner (Fig. 171). 

 Hypertrophied nuclei may also come into contact with one another, 

 and fuse into irregular masses ; and the nuclear hypertrophy affects 

 not only the inf ected host-cell, but also neighbouring cells (Schuberg). 

 According to Mercier, a species of Pleistophora parasitic in the cells 

 of the fat-body of the cockroach stimulates the cells to multiply, 

 with mitosis of the nuclei, and so form neoplasial growths. These 

 facts are of considerable interest from the point of view of the 

 growth of tumours. 



Fio. 171. Section of a tcstis-tubule of a barbel infected by Pleistophora longifilis, 

 showing the cysts of the parasite (P., P. ) and the greatly hypertrophied tissue- 

 nuclei (N., N,). After Schuberg. 



Corresponding with the two types of the parasite mentioned above, there 

 are two methods of development to be distinguished in the trophic phase. 

 As an example of the first, Nosema bombycis, of which the development has 

 recently been described in full detail by Stempell (785), may be selected ; 

 while Qlugea anomala (Stempell, 784) is an example of the second type. 



The development of Nosema bombycis in the silkworm (Fig. 172) begins 

 with small uninucleate amcebulae, which are found first free in the digestive 

 tract, and later in the lymph-channels (Fig. 172, 5-8) ; they multiply by 

 simple fission and wander all over the body, and are hence termed planonts 

 (i.e., wanderers) by Stempell. After a time the planonts penetrate into cells, 

 and there grow larger, assume a definite oval or spherical form, and 

 become " meronts " or schizonts, which multiply by binary or multiple 

 fission until they have filled and exhausted the host-cell (Fig. 172, 9-13) ; 

 but they do not pass into other cells. The multiplication of the meronts may 



