1058 PARASITES OF PROTOZOA 



Parasitized euglenid flagellates lose their green color, chlorophyll 

 first being affected and chromatophores degenerating (Dangeard, 

 1889b, 1895; Puymaly, 1927; Mitchell, 1928; Jahn, 1933). Puymaly 

 found a decrease in flagellar activity, whereas euglenoid movement con- 

 tinued to the last moment and became even more energetic. There is 

 alteration of the nucleus, according to some, though Puymaly stated 

 that there is none; and the cytoplasm becomes vacuolated. Finally, in 

 many cases, the flagellate ruptures and zoospores are liberated. 



Chatton and Brodsky (1909) found that parasitized amoebae tend to 

 assume a spherical form with radial pseudopodia, instead of progressing; 

 and Sassuchin (1928a) noted a progressive slowing of the ciliary 

 action in Nyctotherus. The pulsating vacuole in these heavily infected 

 hosts slows or loses its rhythm. Degenerative changes were observed 

 in the nucleus of parasitized lodamoeha hiltschlii by Wenrich (1937); 

 in that of Entamoeba citelli by Becker ( 1926) ; and in the macronucleus 

 of Nyctotherus by Sassuchin (1938a). When the sporangium ruptures, 

 or shortly before, the host may perish (Chatton and Brodsky, 1909; 

 Mattes, 1924; Yuan-Po, 1928; Sassuchin, 1928a), especially if the in- 

 fection is heavy. 



The fact that in amoebae of man the parasites have been found only 

 in trophozoites has been taken to indicate either that they hinder the 

 amoebae from encysting or that infected cysts degenerate rapidly (Lwoft, 

 1925 ) . Lwoff therefore pointed out a possible use of Sphaerita as a means 

 of biological control, following N511er's suggestion that it might be 

 worth while to devote more attention to these natural enemies of 

 amoebae. If one could transmit the infection to carriers of cysts, Lwoff 

 stated, there would be a means of diminishing the number of cysts, 

 this in addition to the inhibition of multiplication. The practicability 

 of this, however, is doubtful. 



The protozoan whose nucleus is parasitized by Nucleophaga con- 

 tinues activity until the end. Usually there is no apparent change in 

 protoplasmic activity or in structure, aside from the nucleus, even though 

 all stainable chromatin material has disappeared. Lavier (1935a) ob- 

 served increased size and activity in parasitized Entamoeba ranarum, and 

 remarked that the hyperactivity may be provoked by irritation, and may 

 constitute a defense reaction on the part of the amoeba. By the time the 

 parasite reaches the stage of sporulation, however, some changes may 



