OBSEEVATIONS ON VARIOUS SPOEOZOA. 299 



sections show that the capsule is formed by a reactive in- 

 flammatory process, and that between its fibres lie compressed 

 muscle-fibres (fig. 23, a). Those muscle-fibres which are 

 embedded in the deeper, i.e. older part of the capsule, are 

 distended by young sarcosporidia, which present a definite 

 nucleus and a clear protoplasm (fig. 23, b). Next to the 

 capsule come large spaces (fig. 23, c), filled with sickles. The 

 spaces result from the distension of muscle-fibres and the 

 consequent separation of the fibrous fasciculi of the capsule. 

 It may be noted that some of the sickles in the spaces close to 

 the capsule are subdivided into segments. I may add that 

 whilst the sickles contain particles of chromatin throughout 

 the whole of their substance, the youngest parasites have a 

 definite nucleus and a clear protoplasm. L. Pfeifiier has thus 

 shown that progressive inflammatory changes, cyst- and 

 tumour-formation may be determined by Sarcosporidia. 



Finally Dr. Pfeifler's sections of the muscles of frogs show 

 that like the Myxo- and Sarco-sporidia, the Microsporidia occur 

 within muscle-fibres. Fig. 22 shows the remains of a muscle- 

 fibre containing some of these parasites. One group of spores 

 are not yet liberated from the parent cell, and present a 

 central nuclear spot and an unstained peripheral region. The 

 free spores are minute (2 fx) bodies, most of them slightly 

 curved, so that they present the strongest possible resemblance 

 to a collection of vibrios. 



I cannot close this article without expressing my warm 

 thanks to Dr. L. Pfeifl'er for the liberal manner in which he has 

 answered my request for specimens and material. 



London; December 27th, 1894. 



