302 



THE PATHOGENIC RHIZOPODA 



allogromia in the sense of Rhumbler's organism of that name, but that 

 it is a species of a still more striking intracellular rhizopod first 

 described by Dangeard in 1895, under the name of Nucleophaga 

 amebce and subsequently identified by Gruber, Penard, and Doflein. 

 It is a fairly common parasite of Ameba proteus and similar fresh- 

 water forms, penetrating the nuclei and forming relatively large 

 spherical reproductive bodies within the nuclear membrane (see 

 Fig. 117). The nucleus becomes more and more hypertrophied with 

 growth of the parasite, until finally the membrane gives way and the 

 mass of spores is left in the enucleated body of the host. Under 

 the name of Karyoryctes cytorydoides the author described a similar 



Fig. 118 







 »-:•': 



r-r^K 





-A,'- 



Nucleophaga, sp., an intranuclear parasite in the macronucleus of Paramecium aurelia. 



(After Calkins.) 



intranuclear parasite of Paramecium aurelia in 1904 (Fig. 118). 

 Being unfamiliar at the time with Dangeard's work, I was under the 

 impression that the parasite in question was a new organism, and 

 described it as such, pointing out its close resemblance to the intra- 

 nuclear forms of the smallpox organism. There is no doubt, however, 

 that the parasite is a species of nucleophaga, and the name karyoryctes 

 must go. The striking similarity between the smallpox organisms and 

 these intranuclear parasites leaves little room to doubt the close rela- 

 tions of the two, while the structures and life phases, also, of neuroryctes 

 are almost identical with those of nucleophaga (Fig. 120). We are 

 justified, therefore, at least until more convincing evidence to the con- 

 trary is forthcoming, in regarding the Guarnieri bodies of vaccinia and 



