1034 PARASITES OF PROTOZOA 



multinucleate bodies occur in consequence of abundant nutrition, and it 

 is not proved that the bacteria are parasites. 



Schhomycetes in C'lliophova and Sporozoa. — Bacterial parasites of the 

 nucleus and the cytoplasm have been observed repeatedly in free-living 

 ciliates, and some of these have been studied more intensely than any 

 other bacteria in Protozoa. They are of considerable interest, too, in the 

 history of protozoology, having frequently come to the attention of stu- 

 dents, in the latter half of the nineteenth century, and having been 

 variously interpreted. 



J. Miiller (1856) considered the question of spermatozoa in In- 

 fusoria, on the basis of observations by himself and his students, Lieber- 

 kiihn, Claparede, and Lachmann. They observed undulatory filaments in 

 the cytoplasm of Stent or (which were parasites, as discussed below), 

 and found fine curved threads in hypertrophied nuclei (macronuclei) of 

 Parameciujii "amelia" {=caudatmi2) . Miiller commented on the presence 

 of these threads in what Ehrenberg had regarded as a seminal gland, 

 but did not commit himself as to their real nature. Claparede and Lach- 

 mann (1857; 1860-61, p. 259) reported the observation of immobile 

 rods in the nucleus of Chilodon cucullulus and in Paramecium. Believing 

 that the nucleus plays an important role in "embryo formation" 

 {Sphaerophrya), they advanced the hypothesis that it may at certain 

 times play the role in some individuals of a testis, in others of an ovary 

 (1857). Stein (1859) observed hypertrophied macronuclei of Para- 

 mecium "aurelia" [=icaudatum) containing fine, straight rods. He stated 

 that he was at first inclined to regard individuals with such nuclei as 

 males, the nucleus functioning as a testis and producing spermatozoa, 

 while in others it had the role of an ovary. Later, he concluded that the 

 spermatozoa developed in the nucleolus (micronucleus), then penetrated 

 the nucleus, and he pointed out the analogy with fertilization in Volvox. 



Balbiani (1861) observed the rods in nuclei of the same species of 

 ciliate, and noted, as had the others, that they were immobile. He con- 

 cluded that they are parasites, which develop in the interior of the 

 female reproductive organ, and pointed out fundamental differences 

 between them and the "spermatic filaments" enclosed in the "nucleolus" 

 of this animal. It was then Balbiani's contention, developed in 1858 

 (1858a, 1858b), that Infusoria are hermaphroditic sexual animals, the 

 nucleus (macronucleus) an ovary, and the nucleolus (micronucleus) 



