THE PATHOGENIC RHIZOPODA 



309 



formations are phases in the development of the idiochromidia. 

 Without going into the controversy again as to whether or not these 

 bodies are organisms, a matter, I may add, which is not yet settled to 

 the satisfaction of either pathologists or biologists, I will here give only 

 an interpretation of the questionable structures on the basis of their 

 probable relationship to neuroryctes and the other parasitic rhizopods 

 like nucleophaga, a relationship of which I am fully convinced. 



The youngest forms of the parasite are small, spherical, and appar- 

 ently homogeneous granules measuring about half a micron. In 

 slightly larger forms a central granule can be detected more easily in 

 the cornea cells of inoculated rabbits than in the human skin. Dif- 

 ferentiation of the organism follows with growth, two substances of 

 the cell indicating differentiation. One of these is distinctly chroma- 



Section of the lower part of the epidermis, showing the cytoplasmic stage of cytoryctes 

 in the epithelial cells. X 1000. 



toid, and becomes diffused throughout the body of the parasite at first 

 in irregular clumps (Fig. 122), later in a fine network (Fig. 123). Such 

 a structure is to be compared with the chromidiennetz of the rhizopods. 

 As with the chromidia material of the free forms, small, spherical, 

 deeply staining nuclei are formed out of this chromidial substance, 

 the organism then assuming an appearance strikingly like the figure 

 of arcella as given by Hertwig, in 1899 (compare Figs. 46 [p. 118] and 

 123). These granules are not artefacts, but developmental stages of 

 the organism. The proof of this is given by the fact that they may be 

 distinguished after any of the ordinary differential nuclear stains, but 

 more surely by the fact that their presence is indicated by photographs 

 made with the ultraviolet rays from unfixed and unstained living 

 tissue of the inoculated cornea. These granules were interpreted as 

 gemmules in 1904, and as vegetative spores or merozoites I would 



