200 



SPOROZOA. 



them is still very far from satisfactory or complete, although they 

 are of most common occurrence in our domestic animals, pig, ox, 

 sheep, and even deer. 



The first to notice these curious forms was Miescher, who observed 

 the muscles of a domestic mouse penetrated in the direction of the 

 fibres by long strips, visible even to the naked eye, which on closer 

 examination appeared as cylindrical tubes filled with countless minute 

 kidney-shaped bodies. 1 Similar though shorter tubes were seen by 

 Hessling in the muscles of the roe and other Mammalia, and indeed 

 inside the muscular fibres, 2 still surrounded on all sides by the striated 

 sarcous substance. The observations of Eainey, who thought he had 

 in the tubes the first stage of the common bladder- worm of the pig, 3 

 and subsequent observations of my own, 4 proved that this occurrence 

 inside the muscular fibre was constant (Figs. 103 and 104). They 

 have not as yet been found anywhere else, although numerous observers 

 have in the meantime devoted close attention to them. 6 



.. 





FIG. 103. Rainey's tubes, enlarged about 

 40 diameters. 



FIG. 104. One of Rainey's 

 bodies within an isolated muscu- 

 lar fibre, enlarged 100 diameters. 



As long as the muscular fibres have their normal extension, the 

 tubes preserve an elongated form ; but this is altered, and gives place 



1 Bericht iiber die Verhandl. d. naturforsch. Gesdlsch. zu Basel, p. 143, 1843. 

 Figured by v. Siebold, Zeitschr.f. wiss. ZooL, Bd. v., tab. x., Fig. 10, 11, 1854. 



2 Zeitschr. f. wiss. Zool, Bd. v., p. 196 et seq., 1854. 



3 Phil, trans., vol. cxlvii., p. 114 et seq., 1857. 



* Loc. cit., where Rainey's mistake was corrected. 



r> Of the numerous papers on these organisms, I may specially mention Manz, " Beitrag 

 zur Kenntniss der Miescher'schen Schlauche," Archiv }. mikrosL Anat., Bd. iii., p. 

 345 ct seq., 1867. 



