PROTOZOAN -LIKE BODIES IN SMALLPOX 



523 



them. This accounts in part for the varied results reported. However, in 

 the most perfectly prepared specimens, judged according to the appear- 

 ance of the red blood cells, leukocytes, and tissue cells at a distance 

 from the lesions, we have found the vaccine bodies, especially in corneal 



FIG. 160 





Epithelial cells of a rabbit's cornea, containing " vaccine bodies." Tissue fixed three days after inocu- 

 lation with smallpox virus, a and d, vaccine bodies ; b and c, nuclei. X 1500 diameters. 



infection, to show a more or less constant series of changes, somewhat 

 similar to those described by Calkins in his "gemmule formation" 

 and by Tyzzer in his development of the vaccine bodies. This series 

 of changes might be represented somewhat schematically in Fig. 161. 



FIG. 161. 



Schematic representation of vaccine bodies seen within the epithelial cells in the lesions of smallpox 

 and vaccinia : 1, spore (merozoite, sporozoite ?) ; 2, small form which stains solidly with basic stains ; 

 3, larger form which contains central, more darkly staining granule ; 4, larger form, with more lightly 

 staining reticular cytoplasm. This form and the next may have amoeboid outline, and there may be 

 larger am<eboid forms which might be interpreted either as the grown single form or as the fusion of 

 two or more forms ; 5, form containing two central, darkly staining bodies ; 6, form containing many 

 bodies taking basic stains more or less intensely; 7, form containing a central body staining faintly 

 with basic dyes, and small rounded bodies about it, some taking basic and some acid stains ; 8, same 

 as 7, except that many of the bodies surrounding the central body are definitely ring-shaped, and all 

 take the acid stain. These forms vary in size ; some are larger than the host nucJeus ; 9, form break- 

 ing up (spores set free?). 



( )ne can easily see that such tiny bodies as these possible spores with 

 no definite characteristic Maining (jualities would be with difficulty, 

 if at all, differentiated from the mass of cell granules in the degenerated 

 areas of the lesion, and, as the outline and structure of most of the other 

 forms seem to be easily disturbed, the whole question as to their nature 

 is, from a morphological standpoint alone, a very diffcult one to settle. 



