319 
lymphatics. It is easy to understand that the organisms in a focus of 
variolous pneumonia might invade the adjacent blood vessels, infect 
endothelial cells, and so be carried throughout the vascular system. If 
such an infected endothelial cell were to lodge in a capillary adjacent 
to an epithelium hospitable to the organism, an eruptive lesion would 
result. The focal lesions in the seminal vesicles of one of the monkeys 
which was inoculated in the trachea is doubtless due to such a process, 
although in this case the infected endothelial cells probably came from 
vessels beneath the tracheal inoculation. In variola inoculata the tissue 
at the site of the inoculation is flooded with organisms at the time of 
inoculation, and it seems probable to us that the exanthem developing 
in these animals results from endothelial cells infected at this time. In 
variola vera the exanthem appears four or five days later than in variola 
tnoculata. We believe this interval to be associated with the develop- 
ment of a focus of variolus pneumonia, during which the organisms 
multiply and finally invade the vessels. 
CONCLUSIONS. 
(1) Inoculation of the mucous membrane of the trachea of the monkey 
(M. cynomologus) with variola virus produces a variola inoculata in that 
animal. 
(2) Inhalation of variola virus by the monkey (M. cynomologus) 
produces a variola inoculata in that animal. 
(3) Exposure of the monkey (J. cynomologus) and the orang-utan 
(Simia satyrus) to smallpox fomites and to a smallpox patient does not 
produce vartola vera or any other recognizable form of variola in these 
animals. 
(4) Inoculation of the moucous membrane of the trachea of the 
monkey (M. cynomologus) with variola virus is followed by the develop- 
ment of a variolous lesion on the mucous membrane which is similar to 
that produced on other mucous membranes by similar inoculations. A 
variolous lesion may develop in the bronchi and be associated with a 
pneumonia in which Cytoryctes variole are present. The development of 
the specific lesion in the trachea may be followed by a general cutaneous 
exanthem and also by focal lesions of a variolous nature in the seminal 
vesicles. 
(5) Cytoryctes variole can:invade the epithelial cells of the trachea, 
the bronchi, the alveoli of the lung, and the seminal vesicles. 
(6) Cytoryctes variole can invade the endothelial cells of lymphatics 
and blood vessels. This property of the organism plays an important 
part in the production of the exanthem in variola. 
