CHAPTER XXXIX. 



THE MICRO-ORGANISM OF SMALLPOX AND COWPOX. 



No bacteria have been found in smallpox which 

 seem to have any relation to the disease except as 

 secondary infections. The same is true of vaccinia. 

 In both the smallpox and vaccinia papules, vesicles, 

 and pustules, L. Pfeiffer and others have constantly 

 found small, homogeneous bodies in the epithelial cells 

 surrounding the lesions. These little bodies are in the 

 cell substance, not in the nucleus, and usually but one 

 or two exist in any one cell. They are regularly 

 missed in the skin when vaccination has failed, and 

 also in similarly appearing papules and pustules in 

 pyaemia, acne, etc. They apparently belong to the 

 class of protozoa, and from their constant presence are 

 believed to be the probable specific micro-organisms of 

 both diseases. They are at first about double the size 

 of the staphylococcus and increase to double that size 

 (see Fig. 87, p. 651). Similar bodies have been noted 

 in the blood. In a great many specimens of skin from 

 cases of variola and vaccinia examined by Williams in 

 the health department laboratories these bodies have 

 never been entirely missed in the epithelial cells sur- 

 rounding the lesions 



The Connection Between Smallpox and Cowpox. The 

 inoculation of the virus of smallpox into calves 

 produces, when successful, in the first series moderate 



