PARASITES OF PROTOZOA 1039 



Hetherington (1932) mentioned an extensive cytoplasmic invasion 

 of Stentor coenileus by bacilli, the ciliates losing their bright blue-green 

 color and some of their capacity for motor response. Pale stentors from 

 mass cultures are, he stated, often infected with a great number of 

 bacilli. Numerous instances of physiological regeneration occurred in the 

 recovery of these animals. The report did not indicate whether the 

 bacilli were isolated or grouped. 



In the cytoplasm of Spirostomum amhlguum, a motile spirillum was 

 found in large numbers by Takagi (1938). He studied nine ciliates and 

 found all infected, and considered it probable that all in the culture 

 were parasitized. One hundred and six were present in one ciliate; in 

 another, 10 of the 67 were undergoing binary fission. A flagellum was 

 detected at one end of the parasite, which swam about actively in the 

 cytoplasm. Takagi stressed the fact that his is the first report of a cyto- 

 plasmic parasite with active motility in a protozoan. He did not com- 

 ment, however, on the observations by Miiller, Claparede and Lachmann, 

 and Stein, nor on that by Kirby. Miiller (1856) mentioned observations 

 by himself, Lieberkiihn, Claparede and Lachmann of motile threads 

 in Stentor; and the isolation of these by the last-named observers, 

 when their motility soon disappeared in the water. Biitschli (1889, p- 

 1831 ) discussed these observations in his account of parasites of ciliates. 

 The threads occurred in the vacuoles in bundles, and displayed active 

 movement. Claparede and Lachmann (1857) thought their parasitic 

 nature not improbable, noting their great similarity to certain vibrios. 

 Biitschli, while admitting that the threads might be ingested food, be- 

 lieved it more likely that they were parasites. These forms differed from 

 Takagi's in being in bundles instead of isolated. 



Mangenot (1934) found rhodobacteria sufficiently abundant in a 

 ciliate identified as Spirostomum teres to impart to it a rose color. They 

 were distributed mostly in the peripheral cytoplasm. He regarded the 

 relationship between them and their host as parasitic or symbiotic, and 

 compared the "rhodelle" association to that with chlorellae, xanthellae, 

 and cyanellae. 



Irregular aggregations of minute granules (Fig. 217D) were found 

 in the cytoplasm of many individuals of Nyctotherus ovalis by Sassuchin 

 (1928a, 1934). He made various microchemical tests, excluding the 

 possibility that these were glycogen or glycoprotein granules, chondrio- 



