CHLAMYDOZOA 



209 



and division. The mode of division of the Chlamydozoa resembles 

 that of the centriole of a cell, by the formation of a dumb-bell-shaped 

 figure. Two dots are observed connected by a fine line or strand 

 which becomes drawn out and finally snaps across the middle. 

 Prowazek and Aragao (1909) working on smallpox in Rio de Janeiro 

 found that the chlamydozoal granules passed through a Berkefeld 

 filter and that the filtrate was virulent. But if an "ultra-filter" were 

 used, i.e., one coated with agar, then the granules were retained and 

 the filtrate was no longer virulent. The surface of the ultra-filter was 

 found to contain many granules. 



The Chlamydozoa are parasites of epiblastic tissues (e.g., epidermal 

 cells, nerve cells, conjunctival cells). 



The life-history of a Chlamydozoon (fig. 119), such as that of 



FIG. 119. Chlamydozoa. Trachoma bodies in infected 

 epithelial cells of the conjunctiva, (a) initial bodies (above) 

 and cluster of elementary bodies (touching the nucleus); 

 (b) cluster of granules surrounded by mantles, x 2,000 

 approx. (Original. From preparation by Fantham.) 



vaccinia, is, according to Prowazek, Hartmann and their school, as 

 follows : 



1. The infection begins with elementary bodies or elementary 

 corpuscles which live at first extracellularly. An elementary body is 

 a minute speck of chromatin, apparently devoid of cytoplasm, which 

 can pass through a bacterial filter. It can enter a host cell, but the 

 entry is not a process of phagocytosis. 



2. Inside the host cell the elementary body grows in size, and 

 becomes an initial body (fig. 119, a). 



3. A reaction on the part of the host cell results, for nucleolar, 

 plastin substance is extruded from the cell-nucleus and surrounds 

 the parasitic initial body. The latter is thus enveloped in a mantle 

 (hence the name Chlamydozoa, from ^Aa/w, a mantle), and the 

 characteristic cell-inclusion (Guarnieri's body, Negri's body, etc.) is 

 produced. The nucleolar, mantle substance probably represents the 

 " cytoplasm " of Cytoryctes, described by Calkins. 



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