SARCOSPORIDIA 



the numerous bodies thus originated are nucleated and become 



spores direct. 



The process commences in the centre of the cylinders, arid 



then progresses towards the extremities, the parasites meanwhile 



increasing in size, and new sporoblasts being continually formed 



at the extremities (fig. 60). 



The spores vary in shape according to the 

 species, but are also of different form in- 

 dividually ; they are mostly kidney-, bean- or 

 sickle- shaped, and of a very small size. They are 

 apparently surrounded by a membrane, and at 

 one extremity (according to the discovery of 

 L. Pfeiffer, confirmed by van Eecke, Laveran 

 and Mesnil) contain an obliquely striated body 

 (fig. 61) understood to be the pole capsule, 

 while the greater part of the spore is taken 

 up by the nucleated sporozoit. 



Several authors state that they have also 

 observed filamentous appendages at one pole of 

 the spores, and have seen two sorts of spores 

 in the same Sarcosporidium, but these observa- 

 tions require confirmation. 



The duration of life of the Sarcosporidia 

 is a comparatively long one ; the affected mus- 

 cular fibres may remain intact and capable of 

 performing their functions for a lone: time, but 



FIG. 60. Termina- 

 tion of a Sarcocystis at last they perish, if the host lives long enough, 



Zptogrof^ptg 6 so that the sarcosporidia of the muscles are 

 800/1. (After Bertram.) then enveloped only by sarcolemma, and finally, 

 when this likewise disappears, they fall into the 

 intra-muscular connective tissue. In many cases the sarcosporidia 

 die off within their hosts, this, according to Bertram, being brought 

 about by a disintegration of the spores in the central chambers ; 

 in other cases the leucocytes play a part in the destruction of the 

 sarcosporidia, and finally, it is a common occurrence for lime salts to 

 be deposited in and around the vacant cylinders. 



The manner in which the hosts become infected is entirely 

 unknown, although transmission must occur very frequently, as in 

 some places pigs, sheep, mice and rats are infected to a remark- 

 ably high percentage, indeed, not far below 100 per cent. Young 

 animals also show that they are already infected, and perhaps 

 infection only takes place during youth. As most of the hosts 



