SMALLPOX AND COWPOX. 651 
prepared it is much more durable than when dried on 
ivory points or quills. 
The Appearance of the “ Vaccine Organism.” Williams 
has described the appearances observed as follows : 
“The epithelial cells of the skin in the infected areas 
of vaccinated calves contain characteristic bodies. These 
bodies are generally spheroidal, but may be quite irreg- 
ular in outline. They vary in size from that of a 
Fic. 87. 
Epithelial cells of sebaceous gland of hair containing vaccine bodies. 
V. Homogeneous vaccine bodies. N, Granularnuclei. > about 600 diam. 
particle of nuclear chromatin to that of the nucleus 
itself, and are sometimes even larger. Usually they 
are about one-fourth the size of the nucleus. They 
are seen only in the body of the cell, never in the 
’ nucleus, and generally only one is seen in each cell, 
though there may be three or four. They take most 
nuclear stains rather more faintly than the nucleus, 
and are distinguished, moreover, by their homogeneous 
